JPH09299948A - Water treatment device and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong the service life of a water purifier by providing an electronic field water treatment device on the upstream part of the water purifier. SOLUTION: In the case of treating water, a hydrotreater 1, an intermediate tank 2 and a reverse osmosis membrane filter 3 which are an electronic field treatment device are connected through piping 4, 5 successively. A raw water feeding port 123 in the lower part of a treating part 12 of the hydrotreater 1 and a primary clean water discharge pipe 124 in the upper part thereof are connected to a raw water feeding pipe 125 and a primary clean water discharge pipe 126 are connected respectively. The primary clean water discharge pipe 126 is connected to the raw water feeding port 123 with a bypass pipe 127, and a pump 6 is interposed in the piping 5. The hydrotreater 1 receives a signal from an electron generator by an electronic induction electrode and sends it to an electronic charger which is a cathode through water. This electronic charger sends electrons corresponding to the received signal to the electronic induction electrode which is an anode through water. In this way, water is subjected to electronic field treatment to discharge it as primary clean water from a primary clean water discharge port 124.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water treatment device and a water treatment method using a water purifier represented by, for example, a reverse osmosis membrane filter, and to extend the usable period of the water purifier. The present invention relates to a water treatment device and a water treatment method that enable the above.

[Prior art]

Various water purifiers which meet these purposes are widely used for various purposes such as medical purposes, recovery and recycling of water resources, and industrial purposes. Especially in clean water for manufacturing integrated circuits and medical treatment, endotoxin (toxin derived from gram-negative bacteria) contained in clean water deteriorates quality of the integrated circuit as a product, and
As it becomes a pyrogen for the animal body,
It is said that the endotoxin concentration must be low. On the other hand, in the conventional water purification method, the endotoxin concentration of the clean water is affected by the pollution degree of the raw water, so that the desired clean water with a low endotoxin concentration cannot be easily obtained, and a large amount of the desired clean water with a low endotoxin concentration is obtained. In addition, it is expected to be easily manufactured.

For example, various kinds of clean water such as diluting water for hemodialysis fluid are used in a large amount for medical purposes. For such clean water, raw water such as tap water from which solids have been removed by filtration and / or coagulation / sedimentation is usually passed through a reverse osmosis membrane filter using a semipermeable membrane module. The water obtained as filtered water is used. Although there is an advantage that good quality clean water can be obtained in this method, on the other hand, the quality of filtered water is easily affected by the quality of raw water, and with the passage of time,
The membrane module is contaminated and the solute rejection rate (below
The performance of the membrane module is generally deteriorated, such as a decrease in the water content) and a decrease in filtered water.

It is possible to prevent such deterioration of performance, or
In order to recover the once degraded performance, a cation exchange resin device and an activated carbon adsorption device are connected in series on the upstream side, or various pretreatments such as pretreatment of raw water with magnetism are performed. Various treatments such as cleaning the membrane module whose performance has deteriorated with aqueous solutions of citric acid, oxalic acid, EDTA, various surfactants and chemical substances such as formaldehyde were tried, but prevent the deterioration of the performance of the membrane module. In addition, even if it was not possible to recover the performance of the membrane module that once deteriorated, or even if it could be recovered, there is a considerable time immediately after such processing until the performance is recovered. I needed it.

In addition, the inventors of the present invention, in order to make the filtration capacity of the membrane module to a great extent in order to obtain the filtered water of high quality in the filtration by the reverse osmosis membrane filter,
keeping the pH and the pH in the membrane module of the reverse osmosis membrane filter approximately neutral to slightly alkaline, and / or
It was also confirmed that it is important to lower the conductivity of raw water as much as possible. However, in reality, the pH and conductivity of the raw water constantly fluctuate greatly, and the pH of the membrane module also fluctuates accordingly, and it is extremely complicated to monitor and adjust such fluctuations. Furthermore, recently, blood purification therapy such as hemodialysis has become widespread, and the amount of dialysate used has significantly increased. Along with this, harmful substances such as endotoxin in diluted water of dialysate have been increasing. Increasing the concentration of unavoidable is a problem. Therefore, stable mass production of clean water with low concentration of such harmful substances and high quality is required.

Therefore, it is further expected to develop a method capable of obtaining high-quality permeated water without being affected by the water quality of raw water and maintaining the excellent performance of the reverse osmosis membrane filter for a long period of time. Reverse osmosis membranes are also used in various water purifiers other than reverse osmosis membrane filters such as so-called hollow fiber filters, which use a module in which many activated carbon filters, sand filters and hollow fiber membranes made of silicone resin are arranged. As in the filter, the quality of the filtered water is susceptible to the quality of the raw water, and the essential factors such as the decrease of the solute rejection rate and the reduction of the permeated water due to the contamination of the filter medium over the use time. It has drawbacks.

[Problems to be Solved by the Invention]

The object of the present invention is to provide a water purifier typified by a reverse osmosis membrane filter capable of retaining the original excellent performance of a filter medium such as a membrane module for a long period of time, and at the same time, treating raw water. The present invention provides a water treatment apparatus and a water treatment method which are effective for obtaining clean water having a low endotoxin concentration by which high-quality permeated water or filtered water can be obtained for a long period of time regardless of the quality of water.

[Means for Solving the Problems]

The inventors of the present invention have conducted intensive studies to overcome the drawbacks of the conventional water treatment apparatus and water treatment method using a water purifier, and as a result, have installed an electronic field water treatment apparatus on the upstream side of the water purifier. By connecting them in series, these disadvantages can be overcome, and a large amount of desired clean water with low concentration of harmful substances such as endotoxin can be easily obtained without being affected by the pollution degree of raw water. The present invention has been achieved based on this new finding.

That is, the first aspect of the present invention is a water treatment apparatus characterized in that an electronic field water treatment apparatus is connected in series on the upstream side of the water purifier. The second invention is a water treatment method characterized in that raw water is passed through an electronic field water treatment device to obtain primary purified water, and then the primary purified water is passed through a water purifier to obtain secondary purified water. is there. Furthermore, the third invention is a water treatment method characterized in that raw water containing endotoxin is sequentially passed through an electronic field water treatment device and a water purifier to reduce the endotoxin concentration in the raw water.

The water purifier in the present invention is not particularly limited as long as it is a filtration type water purifier, but a reverse osmosis membrane filter equipped with a high performance and expensive semipermeable membrane module is used. Most preferred and effective. The reverse osmosis membrane filter is not particularly limited and may be any of a flat membrane module, a spiral module and a tubular module, and a commercially available product can be used as it is. Examples of water purifiers other than the reverse osmosis membrane filter include a so-called hollow fiber filter that uses an activated carbon filter, a sand filter, and a module in which a large number of hollow fiber membranes made of silicone resin are arranged.

The water purifier may be one, but a plurality of water purifiers of the same type or different types may be connected in series. As the latter, in practical use, for example, a plurality of reverse osmosis membrane filters connected in series and a filter other than the reverse osmosis membrane filter connected upstream of the reverse osmosis membrane filter are preferable. . There are no particular restrictions on filters other than the reverse osmosis membrane filter in the latter, but for practical purposes, for example, activated carbon filters, sand filters, and hollow fiber filters are preferable.

The electronic field water treatment apparatus in the present invention electrically neutralizes the charge of water, eliminates the potential difference at the interface (Helmholtz electric double layer), and disperses ions and charged suspended solids. It is a device that makes quantum mechanically "excite the electron state of water molecule" and changes it to "state where electron orbit of water molecule transits to higher energy orbit". It is known that it is essentially different from a device that applies a magnetic field or an electric field or electrolyzes water. Then, the structure may have a cathode and an anode for contacting with water to generate electrons in the water.

As the electronic field water treatment device, at present, only "Hydro Treater" (registered trademark), which is a product of CMC International Co., Ltd., is commercially available in Japan. This hydrotreater can prevent the scale of the cooling water circuit of the refrigerator, the corrosion of the hot and cold water circuit, the corrosion and red water of the hot water supply circuit, the red water of drinking water, the scale of the boiler water supply, and the treatment of chemical and food processing water. Widely used in government offices, public facilities, hospitals and companies.

This hydrotreater has a power source section and a water treatment section. The power supply unit has an electronic generator,
The water treatment unit is a metal cylinder, and an electronic charger having a raw water supply port and a primary purified water discharge port at both ends thereof and a center of the cylinder, one end of which is connected to the power supply unit. And a connected rod-shaped electron induction electrode made of titanium. Thus, the electron charger and the electron induction electrode act as a cathode and an anode when energized, respectively. The metal used for the tubular body of the water treatment section is preferably a metal having high conductivity such as ordinary steel, stainless steel, and titanium alloy. In particular, metals having high rust resistance such as stainless steel and titanium alloys are particularly preferable.

For example, in the case of a metal having a relatively small rust resistance such as ordinary steel, for example,
It is preferable to apply a rust preventive treatment such as zinc plating.
In addition, the power supply unit and the water treatment unit may be structurally connected to each other and integrated, or may be separated from each other. Further, as the electronic field water treatment device, it is possible to use a device having a structure in which both the cathode and the anode are housed in the same tank as the electron charger and the electron induction electrode, respectively.

The operating conditions of the electronic field water treatment device according to the present invention are as follows. That is, the water quality of the raw water supplied to the electronic field water treatment device varies depending on the desired quality and application of the secondary purified water, the type of water purifier, etc., and is appropriately determined. When the water purifier is a reverse osmosis membrane filter, which is for medicinal use such as liquid, the water quality is about the same as ordinary tap water, and the conductivity is substantially free of solid matter, Usually 10-20
It is about 00 μs / cm, preferably about 10 to 200 μs / cm, and the pH is usually neutral to slightly alkaline, preferably about 7.3 to 7.5. The endotoxin concentration is preferably as low as endotoxin limulus activity, but 10,000 to 20,000 EU
It may be about / L (liter). The size of the ground resistance is usually about 10 Ω (ohm) or less, preferably
It is set to about 0 to 3Ω.

The voltage applied to the power supply unit is 100V (volt). Further, the magnitude of the current of the power supply unit is usually determined in the range of about 4 to 100 mA (milliamperes) according to the magnitude of the treatment capacity of the electronic field water treatment device.
The feed rate of raw water varies with various requirements including the quality of raw water, in the case of these various requirements, such as described above, usually, 0.003～2M per volume 1 m ³ of the processing unit
^It is about ³ / sec, and preferably about 0.01 to 1.5 m3 / sec.

In the present invention, the endotoxin concentration of water is represented by endotoxin limulus activity (EU / L). Therefore, this endotoxin limulus activity is, for example, using an endotoxin-specific limulus reagent such as the commercially available endospacy method (product of Seikagaku Corporation) and endotoxin test ES (product of Wako Pure Chemical Industries, Ltd.) It is measured in accordance with "Coloring synthetic substrate method by endospacey-Health and health approval number (04AM) No. 081".

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a partially cutaway side view of a typical example of a hydrotreater which is an electron field processing apparatus according to the present invention. This Hydrotreater 1 has an upper power supply 11 and
The power source unit 11 has a processing unit 12 connected to the lower portion thereof. The power supply unit 12 has a cylindrical shape and has an electron generating device 111 and display lamps 112 and 113. Indicator lamp 112
Either one of 113 and 113 indicates that electrons are being generated, and the other display lamp indicates that the power supply unit 11 is energized. Then, the electronic generator is powered by the power cord 114 to 100V (50 / 60H).
z) connected to the power supply.

The processing unit 12 is a cylindrical body of ordinary steel, and has an electronic charger 121 whose surface is plated with zinc, and the electronic charger 121 is made to coincide with the long axis of the cylindrical body and built in over the entire length thereof. An electron induction electrode made of titanium, which is squeezed and has one end connected to the electron generator.
122 is built in. When the electron generator 121 of the power source unit 11 is energized, the electron charger 121 and the electron induction electrode 122 respectively act as a cathode and an anode. A raw water supply port 123 and a primary purified water drainage port 124 are provided at the lower part and the upper part of the electronic charger that is the processing unit 12, respectively.

FIG. 2 illustrates a flow chart of a typical example of the water treatment device of the present invention. That is, a hydrotreater 1 which is an electron field treatment device, an intermediate tank 2, and a reverse osmosis membrane filter 3 which is a water treatment device are sequentially connected via pipes 4 and 5. The raw water supply port 123 in the lower part of the treatment unit 12 of the hydrotreater 1 and the primary purified water discharge pipe 124 in the upper part are connected to the raw water supply pipe 125 and the primary purified water discharge pipe 126, respectively. The outlet of the reverse osmosis membrane filter 3 is connected to the secondary purified water discharge pipe 7. In addition, the primary purified water discharge pipe 126 is a pipe
Connected to 4. The primary purified water outlet 124 is connected to the raw water supply port 123 by connecting the pipe 4 and the raw water supply pipe 125 with the bypass pipe 127. A pump 6 is interposed in a pipe 5 that connects the intermediate tank 2 to the reverse osmosis membrane filter 3.

Raw water containing no solid matter, such as tap water, and circulating water sent from the bypass pipe 127, if desired, through the raw water supply pipe 125 and the raw water supply port 123 in order are treated in the treatment unit of the hydrotreater 1. It is supplied to twelve electronic chargers 121 and filled in the electronic chargers 121. The electron induction electrode 122 receives the signal from the electron generator 111 of the power source unit 11 and sends it to the electron charger 121 as a cathode through water. The electron charger 121, which is a cathode, sends out electrons corresponding to the received signal to the electron induction electrode 122, which is an anode, via water. In this way, the raw water filled in the electronic charger 121 is subjected to the electronic field treatment and discharged as the primary purified water from the primary purified water outlet 124 of the upper part of the electronic charger 121.

The primary purified water discharged from the primary purified water outlet 124 of the upper portion of the electronic charger 121 is sequentially passed through the primary purified water discharge pipe 126 and the pipe 4, and the intermediate tank
It is sent to 2 and, if desired, temporarily stored here. Further, part or all of the primary purified water that is being discharged from the primary purified water discharge port 124 on the upper part of the electronic charger 121 and is being passed through the primary purified water discharge pipe 126 is a bypass pipe 127, a raw water supply pipe 125, and a raw water, if desired. Supply port
The water is sequentially passed through 123 and returned to the electronic charger 121 as circulating water. The primary purified water stored in the intermediate tank 2 is discharged from the intermediate tank 2 as necessary,
Reverse osmosis membrane filter 3 via pump 6 and pipe 5 in sequence
Sent to The primary purified water sent to the reverse osmosis membrane filter 3 is filtered here and made into secondary purified water. This secondary purified water is discharged from the reverse osmosis membrane filter 3 by the secondary purified water discharge pipe 7.

Experimental Example 1 Effect of pH in Membrane Module on Filtration Action of Reverse Osmosis Membrane Filter A membrane module of a reverse osmosis membrane filter is sequentially washed and injected with an acidic aqueous solution, a weakly acidic aqueous solution and a slightly alkaline aqueous solution according to a conventional method. Then, the aqueous solution discharged from the membrane module was circulated through the membrane module to finally adjust the pH in the membrane module to a predetermined value (7.3 to 7.5). In this way, the filtration ability of the reverse osmosis membrane filter using the membrane module washed and injected with each aqueous solution was examined.

The term "pH in the membrane module" as used herein means the pH of the aqueous solution accumulated and adhering to the membrane module treated as described above, and the value of the pH is discharged from the membrane module. Substantially agrees with the pH value of the aqueous solution immediately after. The performance of the membrane module is indicated by the conductivity (μs / cm) of the permeated water passed through the reverse osmosis membrane filter equipped with this membrane module and the rejection rate (%) of the membrane module calculated from this conductivity. ing.

In each of the experimental examples and examples,
The following measuring instruments were used for conductivity and pH. Electric conductivity: Electric conductivity meter YOKOGAWA SC-82 pH: Glass electrode type hydrogen ion concentration meter Toa Denpa Kogyo HM-1 1P The rejection rate of the membrane module is calculated by the following formula.

That is, the rejection rate of the membrane module = (conductivity of raw water−conductivity of permeated water) × 100 / conductivity of raw water. Solute concentration of each aqueous solution and pH of each aqueous solution Type of solute Type of solute Concentration of solute Concentration of aqueous solution pH of aqueous solution Citric acid 2 W / V% 3.2-3.8 Weakly acidic aqueous solution Formalin 2 W / V% 4. 3 to 6.7 Slightly alkaline aqueous solution Stabilized chlorine dioxide 0.5 to 1 W / V% 7.3 to 7.5 The results are shown in Tables 1 to 3.

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

[Table 3]

In Tables 1 to 3, "pre-value" and "post-value" refer to filtered water before and after pH adjustment of the membrane module, respectively. In these Tables 1 to 3, the high conductivity and the low rejection rate respectively indicate that the membrane module has low filtration ability. According to these Tables 1 to 3, the filtration capacity of the membrane module is
When the pH is neutral to slightly alkaline, preferably 7.3 to 7.5, the filtration capacity of the membrane module is improved, but on the other hand, when the membrane module is acidic or weakly acidic, It shows that it will decrease. From this, it is understood that it is important to keep the pH of the membrane module neutral or slightly alkaline in the filtration of water by the reverse osmosis membrane filter.

Experimental Example 2 Effect of raw water quality on filtration capacity of reverse osmosis membrane filter Effect of raw water quality on filtration capacity of reverse osmosis membrane filter using the apparatus shown in the flow chart of FIG. I checked. That is, the filtered water from the membrane module 81 is supplied to the high pressure pump 82. On the other hand, the rest of the filtered water from the membrane module 81 is stored in the filtered water tank 83. In this filtered water tank 83, the dilution water is added to the filtered water in various proportions from the dilution water supply pipe 84, and the mixed water of both is discharged from the filtered water tank 83, together with the other filtered water, It is supplied to the suction side of the high-pressure pump 82.

The mixed water supplied to the high pressure pump 82 is circulated to the membrane module 81 by the high pressure pump 82 as circulating raw water. A discharge port 15 is provided on the discharge side of the high-pressure pump 82.
And a sampling cock 86 is provided. A larger amount of circulating raw water than the filtered water supplied to the filtered water tank 83 is discharged from the discharge port 85. Further, a part of the circulating raw water is sampled from the sampling port 86 at any time. Here, the conductivity of the circulating raw water can be arbitrarily changed by adjusting the amount of the diluting liquid added to the filtered water.

The circulating raw water at the start of the experiment has an electric conductivity of 4
It was from 00 to 450 μs / cm. After the start of the experiment, the diluted solution was sequentially added to the filtered water to dilute it, and the circulating raw water having a predetermined electric conductivity of at least 7.8 μs / cm was obtained while draining from the drain port. The dilution water had its conductivity and pH set to 3.64 μs / cm and 5.9, respectively. Circulating raw water having a predetermined conductivity was circulated between the membrane module and the high-pressure pump for a certain period of time, and then a sample was taken from a sampling cock to measure the pH of the circulating raw water and the conductivity of the obtained filtered water. The results are shown in a graph in FIG. FIG.
FIG. 4 is a graph showing the relationship between the conductivity of circulating raw water (horizontal axis) and the pH of the circulating raw water and the conductivity of the obtained filtered water (both vertical axes).

From the results shown in FIG. 4, when the conductivity of the raw water is about 400 to 450 μs / cm, the pH of the raw water is about 7.7 or higher, and the conductivity of the filtered water is about 6 μs / cm. Met. While circulating this raw water, dilute it with a diluting solution to gradually reduce its electrical conductivity so that the electrical conductivity of the circulating raw water is approximately 180 μs.
The pH of the circulating raw water is almost proportional to this decrease until
The conductivity of the filtered water and that of the filtered water both decreased gradually to about 7.5 and 3.5 μs / cm, respectively.

As the conductivity of the circulating raw water is further reduced to 50 μs / cm, the ratios of decrease in both the pH of the circulating raw water and the conductivity of the filtered water increase to about 7.3 and about 1. It became 5 μs / cm. When the conductivity of the circulating raw water was further reduced, the pH of the circulating raw water further drastically decreased, but on the other hand, the conductivity of the filtered water turned to increase and then sharply increased. From the results of FIG. 4, in reverse osmosis membrane filtration, in order to obtain filtered water with low conductivity and high quality, the conductivity of raw water must be reduced, but not only that, but the pH of raw water is less than 7 It turns out that you should be careful not to do this.

Example 1 Raw water was filtered by a reverse osmosis membrane filter to prepare dilution water for a hemodialysis solution. The membrane module was introduced in September 1991. After that, until October 1995, 2-3
Once a month, the membrane module was washed and disinfected with an aqueous solution of compounds of various chemical substances. Reverse Osmosis Membrane Filter Model: MRE-RO-M5 (S) Model Specifications: Capacity 1500 liters per hour or more (raw water temperature 20
℃) 5 spiral modules for medical use Built-in module material Polysulfone Raw water utilization 70% Adaptation pH range 3 to 10 Adaptation temperature range 5 to 35 ℃

Operating Conditions of Reverse Osmosis Membrane Filter Primary Pressure (kgf / cm ² ) 1.95 ± 0.03 to 2.28 ± 0.04 Operating Pressure (kgf / cm ² ) 22.5 ± 0.1 23.6 ± 0.3 Membrane outlet pressure (kgf / cm ² ) 21.3 ± 0.1 to 22.7 ± 0.3 Raw water supply rate (t / hr) 2.7 to 1.66 ± 0.3 02 Discharge rate of filtered water (t / hr) 1.4 to 1.66 ± 0.02

[0039]

[Table 4]

[0040]

[Table 5]

The concentrations of aqueous solutions of various chemical substances were as follows. Type of chemical substance Concentration of aqueous solution of chemical substance Citric acid 2 W / V% Formalin 2 W / V% Stabilized chlorine dioxide 0.5-1 W / V% Citric acid and stabilized chlorine dioxide 2 W / V%, 0 0.5-10 W / V% Oxalic acid 1 W / V%

From October 1995, introduction of a hydrotreater as an electron field treatment device was started, and as shown in FIG. 1, a hydrotreater was connected upstream of the reverse osmosis membrane filter to treat raw water. . Model and capacity of hydrotreater S-300 type, maximum 40m ³ / hr Operating condition of hydrotreater 30m ³ / hr, 0.75kg / cm ² G current 20mA (DC) grounding resistance 3Ω or less The result is shown in the graph of Fig. 5. Show.

The results shown in the graph of FIG. 5 indicate that when raw water containing various chemical substances was filtered through a reverse osmosis filter until a hydrotreater, which is an electron field treatment device, was used. Immediately after that, rather, the rejection rate temporarily decreased and the conductivity of the filtered water increased. However, after using the hydrotreater, the rejection rate increased and the conductivity of the filtered water decreased with time.

Example 2 Using the apparatus of the present invention shown in FIG. 1, the endotoxin concentration of filtered water at the outlet of a reverse osmosis membrane filter was measured.
At the same time, the endotoxin concentration in the raw water (tap water) supplied to the Hydrotreater was also measured and found to be 3990 EU.
It was / L. For comparison, clean water was obtained in the same manner except that the hydrotreater of the apparatus was changed to formalin washing. The endotoxin concentration is measured using the endospacy method (commercial product of Seikagaku Corporation) in accordance with the above-mentioned “color synthetic substrate method by endospacing” and expressed as endotoxin limulus activity (EU / L). It has been forgotten. Table 6 shows the endotoxin concentration and the rejection rate at the outlet of the reverse osmosis membrane filtration device.

[0045]

[Table 6]

From the results shown in Table 6, the concentration of endotoxin in the filtered water at the outlet of the reverse osmosis membrane filter can be slightly reduced by washing the raw tap water with formalin. However, on the other hand, it can be seen that the fact that the tap water, which is the raw water, is passed through the hydrotreator significantly reduces the endotoxin concentration of the filtered water at the outlet of the reverse osmosis membrane filter. . Further, by washing with formalin, the endotoxin concentration of the filtered water at the outlet of the reverse osmosis membrane filter is only slightly reduced as described above,
On the 3rd day of washing with formalin, the endotoxin concentration again increased, and the endotoxin exclusion rate decreased remarkably.

[0047]

EFFECTS OF THE INVENTION The device of the present invention and the method of the present invention make it possible to maintain the initial excellent performance of a filter medium such as a membrane module for a long period of time, and to obtain a high quality permeation regardless of the quality of raw water. The quality of water or filtered water is obtained over a long period of time, and it is particularly effective in reducing the endotoxin concentration of water, which is now a major problem.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view of a hydrotreater that is an electron field processing device according to the present invention.

FIG. 2 shows a flow chart of a representative example of the water treatment device of the present invention.

FIG. 3 is a flow chart of an apparatus for investigating the influence of the water quality of raw water on the filtration capacity of a reverse osmosis membrane filter.

FIG. 4 is a graph showing the relationship between the conductivity of raw water and pH, and the relationship between the conductivity of raw water and the conductivity of filtered water.

FIG. 5 is a graph showing changes with time of the rejection rate and the conductivity of filtered water of the membrane module.

[Explanation of symbols]

 1 Hydrotreater 11 Power supply unit 111 Electron generator 112 Indicator lamp 113 Indicator lamp 114 Power cord 12 Processing unit 121 Electronic charger 122 Electronic induction electrode 123 Raw water supply port 124 Primary purified water discharge port 125 Raw water supply pipe 126 Primary purified water discharge pipe 127 Bypass pipe 2 Intermediate tank 3 Reverse osmosis membrane filter 4 Piping 5 Piping 6 Pump 7 Secondary purified water discharge pipe 81 Membrane module 82 High pressure pump 83 Filtration water tank 84 Diluted solution supply pipe 85 Discharge port 86 Sample cock

Claims (5)

[Claims] 1. A water treatment device comprising an electronic field water treatment device connected in series on the upstream side of a water purifier. 2. The water treatment device according to claim 1, wherein the water purifier is a reverse osmosis membrane filter. 3. A water treatment method characterized in that raw water is passed through an electronic field water treatment device to obtain primary purified water, and then the primary purified water is passed through a water purifier to obtain secondary purified water. 4. A water treatment method characterized in that raw water containing endotoxin is sequentially passed through an electronic field water treatment device and a water purifier to reduce the endotoxin concentration in the raw water. 5. The water treatment method according to claim 3, wherein the water purifier is a reverse osmosis membrane filter.