JP2010279870A - Method for producing purified water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing purified water, method capable of stably and inexpensively supply, even when change of usage occurs, high quality purified water that is free from biological contamination such as microorganism, endotoxin, and impurities originating from the micoorganism, and to provide such an apparatus for producing the purified water that is suitable for implementation of the method. <P>SOLUTION: In producing purified water for the use of the medical field and the industrial field by combination of a RO processing apparatus 1 and an EDI apparatus 3, RO processed water is made to flow into the EDI apparatus 3 and cleaned in a state where the operation of the EDI apparatus 3 is stopped (non-energized state). Consequently, endotoxin and microorganism adsorbed in an ion exchange resin inside the EDI apparatus 3 are desorbed and drained from a water discharge line 16. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing purified water for medical use, industrial use, etc., water for pharmaceutical production suitable for carrying out the production method, medical purified water such as artificial dialysis water, and purification for washing in a semiconductor production process. The present invention relates to a manufacturing apparatus for manufacturing water or the like.

  The artificial dialysate is produced by mixing purified water (artificial dialyzing water) and a dialysate stock solution. It is necessary to use purified water that is not contaminated with microorganisms and endotoxin (Non-patent Document 1), and water that is not contaminated with impurities having cytokine-inducing action such as DNA fragments derived from the microorganisms. The manufacturing method is important because it needs to be used.

  Artificial dialysis is performed at medical institutions, but depending on the patient's treatment schedule and symptoms, the number of patients undergoing dialysis often increases or decreases during the morning, afternoon and night shifts of the day, or between days of the week. In some cases, response to an emergency is required. In any case, it is always required to supply high-quality purified water as quickly as necessary. In addition, since artificial dialysis is usually not performed at midnight, the operation of the purified water production apparatus is stopped and the operation is resumed the next morning. It is important to be able to supply a stable supply.

Patent Documents 1 and 2 describe a device and a manufacturing method for manufacturing artificial dialysis water by combining an RO treatment device and an EDI device. Patent Document 1 describes that EDI-treated water is returned to the inlet of the reverse osmosis membrane device and circulated (see paragraph 0039 and FIG. 1). In each patent document, a water storage tank is used. There is no description of the circulation line.
Non-Patent Document 2 describes that a drug injector is provided in the line after the water storage tank device for circulation and cleaning. This method does not solve the problem of the residual sterilizing agent that has been pointed out in the past, and since it is a cleaning method in which the production of purified water is stopped, the production of purified water cannot be performed simultaneously with the washing.

  In addition, there is a great demand for clean purified water that is not contaminated with endotoxin, viable bacteria, and the like as much as possible for washing water used in industrial production lines such as semiconductor manufacturing processes.

JP 2007-252396 A JP 2007-237062 A

Kidney and dialysis separate volume 2006, p33-36, "Practical microbiological tests in dialysis facilities" Kidney and dialysis separate volume 2006, p111-116, “Effects of washing with peracetic acid detergent hemoclean on RO water supply line from RO water tank” Proceedings of the 53rd Annual Meeting of the Japanese Society for Dialysis Medicine (June 22, 2008) (Evaluation of dialysis water using an electric regeneration pure water device)

  Part of the present inventor has announced a purified water production apparatus and production method combining an RO treatment apparatus and an EDI apparatus at the 53rd Annual Meeting of the Japan Dialysis Medical Society (Non-patent Document 3). .

  The present invention adds an unpublished invention at the time of the publication, and further improves the use amount of high-quality purified water free from biological contamination such as microorganisms, endotoxins, and impurities derived from the microorganisms. It is an object of the present invention to provide a method for producing purified water that can be stably and inexpensively supplied even when there is a fluctuation of the above, and a purified water production apparatus suitable for the implementation thereof.

As a means for solving the problems, the present invention
A purified water production method using a purified water production apparatus having a reverse osmosis membrane treatment apparatus (hereinafter referred to as “RO treatment apparatus”), a water storage tank, and an electric regeneration type deionization apparatus (hereinafter referred to as “EDI apparatus”). ,
The method for producing purified water is a method comprising a combination of a purified water production process and a washing process,
The manufacturing apparatus can store treated water from the RO treatment apparatus (hereinafter referred to as “RO treated water”) in the water storage tank, and supplies the treated water stored in the water storage tank to the EDI apparatus. (Hereinafter referred to as “EDI treated water”)
The first line that sends the RO treated water from the RO treatment device to the water storage tank, the second line that sends the water in the water storage tank to the EDI device, and the EDI treated water is returned to the water storage tank that stores the RO treated water from the EDI device. And a third drain line connected to a third drain line for draining flush water.
The purified water production process comprises:
A first step of storing the RO treated water obtained by the RO treatment device by sending it from the first line to the water storage tank;
The RO treatment water stored in the water storage tank is sent from the second line to the EDI device for processing, and has a second step of obtaining EDI treated water,
Further, a part or all of the EDI treated water is returned from the third line to the water storage tank, and the third step is a step having a third step of obtaining a mixed water of the RO treated water and the EDI treated water.
The washing step
In the state where the operation of the EDI device is stopped (non-energized state), it is adsorbed to the ion exchanger by washing the RO-treated water through at least the desalting chamber filled with the ion exchanger in the EDI device. Provided is a method for producing purified water, which is a step of desorbing endotoxin and microorganisms that have been removed, and discharging wash wastewater containing the endotoxin and microorganisms from a drain line for wash water.

In addition, the present invention provides other means for solving the problems,
A purified water production method using a purified water production apparatus having a reverse osmosis membrane treatment apparatus (hereinafter referred to as “RO treatment apparatus”), a water storage tank, and an electric regeneration type deionization apparatus (hereinafter referred to as “EDI apparatus”). ,
The method for producing purified water is a method comprising a combination of a purified water production process and a washing process,
The manufacturing apparatus can store treated water from the RO treatment apparatus (hereinafter referred to as “RO treated water”) in the water storage tank, and supplies the treated water stored in the water storage tank to the EDI apparatus. (Hereinafter referred to as “EDI treated water”)
The first line that sends the RO treated water from the RO treatment device to the water storage tank, the second line that sends the water in the water storage tank to the EDI device, and the EDI treated water is returned to the water storage tank that stores the RO treated water from the EDI device. A circulation line is formed by combining water supply from the EDI device to the water storage tank using the third line and water supply from the water storage tank to the EDI device using the second line,
Furthermore, a drain line for washing water for draining washing water is connected to the third line,
The purified water production process comprises:
A first step of storing the RO treated water obtained by the RO treatment device by sending it from the first line to the water storage tank;
The RO treatment water stored in the water storage tank is sent from the second line to the EDI device for processing, and has a second step of obtaining EDI treated water,
Further, part or all of the EDI treated water is returned from the third line to the water storage tank to obtain a mixed water of the RO treated water and the EDI treated water, and the mixed water is again sent from the second line to the EDI apparatus. It is a step having a circulation step that repeats the fourth step to send and process,
The washing step
In the state where the operation of the EDI device is stopped (non-energized state), it is adsorbed to the ion exchanger by washing the RO-treated water through at least the desalting chamber filled with the ion exchanger in the EDI device. The present invention provides a method for producing purified water and a production apparatus therefor, which are steps for desorbing endotoxins and microorganisms that have been removed and discharging the washing wastewater containing the endotoxins and microorganisms from a washing water drain line.

  By producing medical purified water using the production method of the present invention, high quality free from biological contamination such as microorganisms, endotoxins and impurities derived from the microorganisms even when the amount used varies. The purified water can be stably supplied at a low cost.

The figure which shows the manufacturing flow for demonstrating the manufacturing method of this invention.

  The production method of the present invention is capable of producing purified water having a very low content of microorganisms, endotoxin, and further impurities derived from the microorganism, and the purified water obtained by the production method is used for medical and industrial purposes. Can be applied. Below, it demonstrates as a manufacturing method of medical purified water.

<Production process of purified water for medical use>
With reference to FIG. 1, the manufacturing method of the purified water for medical treatment of this invention and the manufacturing apparatus of the purified water suitable for implementing the said manufacturing method are demonstrated. FIG. 1 is a diagram showing a manufacturing flow. Although not shown, an opening / closing valve (such as an electromagnetic valve) for stopping and starting water supply can be provided between the lines as necessary.

<First step>
The RO pump 4 is operated, and tap water is sent from the raw water supply line 11 to the RO treatment apparatus 1 to be processed to obtain RO treated water. Thereafter, the obtained RO treated water is sent from the first line 12 to the water storage tank 2 to be stored. In addition, the tap water used as raw | natural water can also be pre-processed with a soft water apparatus, activated carbon, a micro filter etc. as needed.

  As the RO processing apparatus 1, a known apparatus can be used. For example, the apparatus type VCR40 series, VCR80 series, NER40 series, NER80 series, SHR series sold by Daisen Membrane Systems Co., Ltd. can be used. Those used in the examples can be used.

  The RO treatment apparatus 1 can use a treatment capacity (treatment water production capacity) of 30 to 5000 L / hr, but is not limited to the above range, and is appropriately selected according to the supply amount of purified water. You can choose.

  The water storage capacity of the water storage tank 2 is preferably 100 to 2000L. The water storage tank 2 can be made of a metal such as stainless steel or a resin such as polyethylene or polypropylene.

  The shape of the water storage tank 2 is not particularly limited, but from the viewpoint of smoothing the flow of liquid by preventing the liquid from remaining inside the tank, a conical structure having a conical bottom or a quadrangular pyramid as shown in the figure. It is preferable that the line 13 is connected to the cone-shaped apex portion.

  The water storage tank 2 has a vent hole with an air filter for preventing contamination of germs and the like from the outside atmosphere, and an ultraviolet lamp can be attached inside for the purpose of sterilization, if necessary.

  It is preferable that a water level meter is attached inside the water storage tank 2 so that the operation of the RO treatment apparatus 1 can be started or stopped according to the water level. For example, the upper limit value and the lower limit value of the water level in the water storage tank 2 are determined in advance, and when the upper limit value is reached, the operation of the RO processing device 1 is stopped, and conversely, when the lower limit value is reached, the RO processing device 1 Let's start driving.

The capacity (V ₃ ) of the water storage tank is V ₁ / V ₃ so as to satisfy the relationship between the amount of EDI treated water per hour (V ₁ ) (L) by the EDI device described later and the average water volume of the water storage tank. Is preferably a ratio of 1.5 to 10.

<Second step>
Next, the EDI supply pump 5 is operated, and the RO treated water stored in the water storage tank 2 is sent from the second line 13 to the EDI device 3 to be processed to obtain EDI treated water.

  The EDI apparatus 3 is a known apparatus having an ion exchange chamber (demineralization chamber), a concentration chamber, and electrode chambers (positive and negative electrode chambers). Deionized water (EDI treated water) is deionized in the ion exchange chamber. ) Can be taken out. Examples of the EDI apparatus include those described in Patent Documents 1 and 2, JP-A-11-244853, JP-A-2001-239270, JP-A-2001-353498, and JP-A-2004-74109. In addition to these, commercially available EDI apparatuses such as EDI system series, trade name MOLSEP (registered trademark) (sold by Daisen Membrane Systems Co., Ltd.), and those used in the examples can be used.

The operating conditions of the EDI device 3 are
The amount of the supply liquid is preferably 50 to 4500 L / hr,
EDI water amount (desalted water amount) is preferably 30 to 4000 L / hr,
The concentrated water flow rate is preferably 5% to 20% of the supply liquid amount,
The applied voltage is preferably 30 to 1000 V, and the applied current density is preferably 0.1 to 1.5 A · dm ² .

  The EDI treated water obtained by EDI treatment of the RO treated water can be obtained by the above first step and second step. However, in the production method of the present invention, the third step and the fourth step are further performed as described below. Although it is characterized by having a combined circulation line, a production method without the circulation step can also be carried out.

<Third step (circulation step)>
Next, the EDI treated water is returned from the third line 14 to the water storage tank 2 to obtain a mixed water of the RO treated water and the EDI treated water. The valve 21 is opened and the valve 22 is closed (the same applies to the circulation process hereinafter). At this time, the entire amount of the EDI treated water may be returned to the water storage tank 2 (total amount circulation) or a partial amount may be returned (partial amount circulation). When returning a partial amount, it is desirable to return 10% or more of the total amount, preferably 10 to 80%, more preferably 15 to 60%. If the return amount is less than 10%, the cleaning effect by circulation is too small, and if it exceeds 80%, the circulation flow rate becomes excessive and the amount used for the production of purified water decreases, leading to an increase in the cost of producing purified water.

  The start of the third process is preferably performed simultaneously with the start of the second process for cleaning the third line 14. When cleaning the equipment and piping up to the purified water intake point before starting the production and intake of purified water, the third step is temporarily omitted and the entire amount of EDI treated water is taken to the equipment and piping up to the water supply point. May be.

<Third step (total amount circulation step and partial amount circulation step)>
In the third step, after the EDI treated water is first returned to the storage tank 2 after the start of operation, until the total amount returned is at least equal to the average amount of water (V ₂ ) in the storage tank 2, the EDI treated water The total amount circulation step for returning the total amount of the water and the partial amount circulation step for returning and circulating the 10 to 80% amount of the EDI treated water can be used.

The amount of water in the water storage tank 2 changes during the circulation operation, and the average water amount (V ₂ ) is from the start of the circulation operation until the lapse of a predetermined time due to the total amount circulation operation and / or the partial amount circulation operation. The average value of Specifically, the amount of water in the water storage tank 2 is measured every 5 minutes and obtained from the average value.

  The total amount circulation process is the total amount of EDI treated water from when the EDI treated water is first returned to the water storage tank 2 after the start of operation until the total amount returned is the same amount to 5 times the average amount of water in the water storage tank 2 Is preferably returned, more preferably the same amount to 3 times the amount. If the total amount returned is less than the average amount of water in the storage tank 2, the cleaning effect of the line and the equipment after the storage tank will be small, and if it exceeds 5 times, the time required for cleaning will be long and uneconomical. .

  By circulating operation so as to satisfy the relationship between the total amount returned and the average amount of water stored in the storage tank 2 in the total amount circulation process, high-quality purified water that is safe for the human body is supplied promptly and inexpensively when necessary. can do.

  In the partial amount circulation step, 10 to 60% amount of EDI treated water is preferably returned and circulated, and more preferably 15 to 40% amount is circulated.

<4th process (circulation process)>
Next, the mixed water in the water storage tank 2 is sent again from the second line 13 to the EDI device 3 for processing. The processing conditions in the EDI apparatus 3 at this time are the same as those in the second step.

In the present invention, the ratio (V ₁ / V ₂ ) of the amount of EDI treated water per hour (V ₁ ) (L) and the average amount of water (V ₂ ) (L) in the water storage tank in the circulation process Is preferably operated so as to satisfy the relationship of 2 to 12, more preferably, the circulation operation is performed so that V ₁ / V ₂ satisfies the relationship of 3 to 10. If V ₁ / V ₂ is less than 2, it takes a long time for washing, and in addition to being unable to produce purified water quickly when necessary, there is a disadvantage that the capacity of the water storage tank becomes large and the apparatus cannot be downsized. When V ₁ / V ₂ exceeds 12, the water storage tank is too small for the EDI processing amount, and the stable operation of the apparatus is hindered.

By circulating operation so as to satisfy the relationship of V ₁ / V _2, the viewpoint of stably supplying high-quality purified water that is safe to the human body even when the amount of use varies due to increase or decrease in the number of patients, etc. In particular, in the third step, it is preferable when a production method combining a total amount circulation step and a partial amount circulation step is applied.

  In the production method of the present invention, treated water is circulated between the third step and the fourth step. For example, when water is taken as artificial dialysis water, the treated water is returned to the water storage tank 2 by partial circulation. The treated water except for can be taken from the line 15 connected to the EDI apparatus 3.

<Washing process>
When the above-described production process of medical purified water is continued, endotoxin (ET), microorganisms, and the like in the ion exchanger and / or ion exchange membrane filled in the ion exchange chamber (desalting chamber) of the EDI apparatus 3 It is considered that the DNA fragment derived from the microorganism is adsorbed and held.

  Therefore, as a result of examining the possibility of desorption of ET, microorganisms, impurities derived from the microorganisms, etc. adsorbed and retained on the ion exchanger or ion exchange membrane in the desalination chamber and releasing them into the EDI-treated water, the desorption is: Whether EDI is energized or not energized is important. Specifically, when EDI is energized, the relationship of adsorption force> desorption force is established, and when EDI is not energized, the adsorption force is <We found that it is a relationship of desorption power.

  When the manufacturing operation is stopped and then restarted (when the EDI device changes from the energized state to the non-energized state), the relationship changes from adsorption force> desorption force to adsorption force <desorption force. It is considered that ET, microorganisms, and impurities derived from the microorganisms adsorbed and held in the salt chamber are desorbed and easily released into the EDI-treated water.

  If the production operation is continued for a long period of time, ET and microorganisms are adsorbed to the adsorption limit (breakthrough point) of the ion exchanger. Even so, it is conceivable that ET, microorganisms, impurities derived from the microorganisms, etc. that cannot be adsorbed outflow or desorb, and are released into the EDI-treated water.

  Therefore, in the present invention, a washing process is added in addition to the manufacturing process described above, and the above desorption treatment is forcibly carried out to wash the ET and microorganisms adsorbed and held in the desalting chamber. It is designed to provide a stable supply of safe and high-quality purified water at a low cost without human pollution.

  In the cleaning process, the operation of the EDI device 3 is stopped (non-energized state), the valve 21 of the third line 14 is closed, and the valve 22 of the drainage line 16 is opened to operate the EDI supply pump 5 to store water. RO treated water in the tank 2 is supplied into the EDI apparatus 3.

  In the washing process, it may be supplied only to the desalting chamber for washing and draining, but from the viewpoint of increasing the removal rate of endotoxin and microorganisms, the ion exchange chamber (desalting chamber) in the EDI apparatus 3 is concentrated. It is desirable to supply all the chambers and electrode chambers (positive and negative electrode chambers). An example of such a cleaning process for all rooms will be described with reference to a case where the EDI apparatus shown in FIG. 3 of Japanese Patent Application Laid-Open No. 2007-237062 is cleaned.

  The EDI apparatus shown in FIG. 3 has a concentration chamber in the center, a desalting chamber filled with one ion exchange resin on each side, and a further concentration chamber on each side. The structure has a negative electrode chamber and a positive electrode chamber.

  The RO treated water is supplied to the two desalting chambers, and also supplied to the concentrating chamber and the electrode chamber. After flowing into the respective chambers, the desalting chamber, the concentrating chamber, and the electrode chamber are washed and discharged from each chamber. The

  The cleaning waste water that has been cleaned inside the EDI apparatus 3 is discharged from a drain line 16 for cleaning waste water. The washing waste water contains ET and microorganisms desorbed from the ion exchange resin.

  The RO treatment water in the washing step is 5 to 15 L / min, preferably 4 to 12 L / min, per 5 L of the desalination chamber filled with the ion exchanger. Pass water for at least 10 minutes, preferably at least 10 minutes, more preferably at least 20 minutes.

The cleaning process
(A) a desired time point during the production of purified water for medical use;
(B) After the production of purified water for medical use,
(C) Before the start of production of medical purified water,
At least once selected from (a) and (b), (a) and (c), (b) and (c), (a) to (c) can be washed, Since ET and microorganisms adsorbed on the ion exchanger are desorbed when not energized, washing is preferably performed at least in (c), and more preferably in (b) and (c).

  According to the production method of the present invention, it is possible to obtain high-quality purified water that is safe for the human body. However, in order to further increase the safety, collection of ion exchange resin pieces, ET, and microorganisms in the middle of the line 15 It is also possible to install a UF device that serves for removal.

  The production method of the present invention can carry out the following methods, but is not limited to these methods.

(Method 1)
<Production process of purified water for medical use>
(1) Start of a circulation process (partial volume circulation process) between the EDI device 3 and the water storage tank 2 / Stop water supply to the RO water storage tank 2 (operation stop of the RO processing device 1).
(2) Intake and start of use of medical purified water / Continuation of some amount circulation process.
(3) Start of water supply to the RO treated water storage tank 2 (start of operation of the RO processing device 1) / stop of the circulation process between the EDI device 3 and the water storage tank 2 as the amount of water in the water storage tank 2 decreases.
(4) Repeat (1) to (3) above.
<Washing process>
Implementation of one or more cleaning steps of (a) to (c).

(Method 2)
<Production process of purified water for medical use>
(1) Start of a circulation process (partial volume circulation process) between the EDI device 3 and the water storage tank 2.
(2) In parallel with the circulation step, the amount of water supplied to the RO treated water storage tank 2 is adjusted (the operation of the RO treatment apparatus 1 is appropriately stopped or started according to the amount of water in the water storage tank 2).
(3) Intake and use of purified water for medical use / Continuation of some amount circulation process.
(4) Adjustment of the amount of water supplied to the RO treated water storage tank 2 (the operation of the RO treatment device 1 is appropriately stopped or started according to the amount of water in the water storage tank 2) / continuation of the partial amount circulation step.
<Washing process>
Implementation of one or more cleaning steps of (a) to (c).

(Method 3)
<Production process of purified water for medical use>
(1) Start of circulation process (total volume circulation process) between EDI device 3 and storage tank 2 / Stop water supply to storage tank 2 of RO treated water (stop operation of RO treatment apparatus 1)
(2) Shifting the circulation process between the EDI device 3 and the water storage tank 2 from the full-volume circulation process to the partial-volume circulation process / Continuation of the stop of water supply to the RO storage water tank 2 (stopping the operation of the RO treatment device 1) .
(3) Intake and use of purified water for medical use / Continuation of some amount circulation process.
(4) Start of water supply to the RO treated water storage tank 2 (start of operation of the RO treatment device 1) / Stop of the partial amount circulation process between the EDI device 3 and the water storage tank 2 with the decrease in the amount of water in the water storage tank 2.
(5) Repeat (1) to (4) above.
<Washing process>
Implementation of one or more cleaning steps of (a) to (c).

(Method 4)
<Production process of purified water for medical use>
(1) Start of circulation process (total volume circulation process) between EDI device 3 and storage tank 2 / Stop water supply to storage tank 2 of RO treated water (stop operation of RO treatment apparatus 1)
(2) The circulation process between the EDI device 3 and the water storage tank 2 is shifted from the total quantity circulation process to the partial quantity circulation process.
(3) In parallel with the circulation step, the amount of water supplied to the RO treated water storage tank 2 is adjusted (the operation of the RO treatment apparatus 1 is appropriately stopped or started according to the amount of water in the water storage tank 2).
(4) Intake and start of use of medical purified water / Continuation of a partial volume circulation process.
(5) Adjustment of the amount of water supplied to the RO treated water storage tank 2 (stopping or starting the operation of the RO treatment apparatus 1 depending on the amount of water in the water storage tank 2) / continuation of the partial amount circulation step.
<Washing process>
Implementation of one or more cleaning steps of (a) to (c).

  According to the manufacturing method of the present invention, since it has a circulation process in which the third process and the fourth process are combined, the inside of the water storage tank 2 and the inside of the EDI device 3 can be repeatedly cleaned. Since the water is circulated and cleaned several times, the purified water in the apparatus can maintain high quality.

  Further, in the production method of the present invention, the total amount circulation step is provided in the third step, so that the inside of the water storage tank 2 can be cleaned in a short time (contamination of endotoxin, microorganisms, and microorganism-derived impurities is extremely small. In addition, by providing a partial amount circulation step in combination with the total amount circulation step, it is possible to stably supply high-quality purified water while maintaining the clean state.

  Furthermore, since the manufacturing method of the present invention has a washing step in the desalination chamber by non-energized operation of the EDI apparatus, the ability to stably supply high-quality purified water can be further enhanced.

  Further, by applying the manufacturing method of the present invention, high-quality purified water that is safe for the human body can be stored in the water storage tank 2 at all times, so that it is possible to easily cope with fluctuations in the amount used.

  The purified water obtained by applying the production method of the present invention can be used for medical purposes (purified water for artificial dialysis, injections, etc.) and for industrial use (wash water in semiconductor production lines, etc.).

(Medical purified water production equipment)
RO treatment device 1: VCR-20P (Daisen Membrane Systems Co., Ltd.)
RO membrane: SV022GV-DRA98
RO treated water volume (permeated water volume): 60 L / hr
Operating pressure: 0.56 MPa
Water storage tank 2: Capacity 200 L, Material: Polyethylene EDI device 3: Device model number OS-100, manufactured by Osmo Co., Ltd. EDI electrode area: 4.2 dm ²
(Measuring device / Measuring method)
Endotoxin measuring device Toxinometer Mini (manufactured by Wako Pure Chemical Industries, Ltd.)
・ Viable count
Measurements were made by fluorescent staining using Panasonic Biooproller BP-2 (manufactured by Panasonic Corporation).

Example 1
The purified water for medical use was manufactured according to the flow shown in FIG. Table 1 shows the EDI operating conditions.
<Production process of purified water for medical use>
(First step)
The pre-treated tap water with activated carbon / prefilter was supplied to the RO treatment apparatus 1 to obtain RO treated water. The RO treated water was sent from the first line 12 to the water storage tank 2 for storage.

(Second step)
The RO treated water stored in the water storage tank 2 was sent from the second line 13 to the EDI apparatus 3 for processing, and EDI treated water was obtained. At this time, the RO treatment apparatus 1 was stopped in order to eliminate the influence of the water quality change caused by the inflow of the RO treatment water.

(Third step)
When the amount of water in the water storage tank 2 reached 41 L, the entire amount of EDI treated water was sent from the third line 14 to the water storage tank 2 to obtain a mixed water of RO treated water and EDI treated water. Valve 21 was opened and valve 22 was closed.

表１から明らかなとおり、全量循環処理により、貯水タンク２中のエンドトキシン濃度は急減し、水質は大きく向上した。ＥＤＩ処理水中のエンドトキシン濃度も、透析用水基準の０．０５ＥＵ／ｍｌを大きく下回り十分満足できる水準であった。 (4th process)
The mixed water in the water storage tank 2 was sent again from the second line 13 to the EDI apparatus 3 for EDI treatment. Between the 3rd process and the 4th process, only the processing of the whole quantity circulation process was performed, and the continuous operation for 66 minutes was performed. When 66 minutes had elapsed, the amount of water in the storage tank 2 was 31 L, and the average amount of water in the storage tank was 36 L. Table 1 shows the measurement results at the start of operation and 66 minutes after the start of operation.

As is apparent from Table 1, the endotoxin concentration in the water storage tank 2 decreased sharply and the water quality was greatly improved by the total amount circulation treatment. The endotoxin concentration in the EDI-treated water was well below the dialysis water standard of 0.05 EU / ml, and was sufficiently satisfactory.

<Washing process>
After the fourth step, the production operation was stopped. The EDI apparatus 3 was turned off (non-energized state).
Thereafter, the valve 21 was closed, the valve 22 was opened, and the RO treatment water in the water storage tank 2 was supplied to the desalination chamber, the concentration chamber, and the electrode chamber in the non-energized EDI apparatus 3 for cleaning. EDI-treated water immediately after non-energized operation, 3 minutes later, 10 minutes later EDI-treated water were collected in a sterilized bottle, and the ET concentration and the number of viable bacteria in each bottle (sample No. 1 to 3) were measured. The results are shown in Table 2. The washing waste water was drained from the drain line 16.
Washing was performed by passing RO water at 1.7 L / min for 20 minutes through a desalting chamber volume (300 ml) filled with an ion exchange resin.

After completion of cleaning, energization of the EDI apparatus 3 was started again, EDI treated water and EDI treated water obtained by performing the first step and the second step for 10 minutes were collected, and the ET concentration was measured. . The operating conditions (the amount of EDI treated water, voltage, and current) of the EDI apparatus are the same as in Table 1, and the ET in the water storage tank 2 and the ET concentration in the EDI treated water in EDI processing are shown below.
ET concentration in the storage tank 2 10 minutes after resuming EDI energization: 145 EU / L
ET concentration in EDI-treated water: 3 EU / L

Reference example 1
After producing purified water by performing the steps from the first step to the fourth step, when performing the non-energized operation in the same manner as in the embodiment, the valve 21 is opened and the valve 22 is kept closed and the EDI treated water is supplied. Without draining, the entire amount was returned to the water storage tank and circulated. The operating conditions of the EDI apparatus (the amount of EDI treated water, voltage, current) were the same as in Table 1. The ET concentration of the storage tank water and the EDI treated water after the circulation of the whole amount of the EDI treated water and the EDI treated water for 5 minutes by the non-energized operation was measured. As a result, the ET concentration of the storage tank water and the EDI treated water during the non-energized operation greatly increased compared with the time of producing purified water, and the water quality deteriorated.
Quality of treated water when EDI is energized:
ET concentration in the water storage tank 2: 140 EU / L
ET concentration in EDI-treated water: 4 EU / L
Water quality after 5 minutes of non-energized operation (no drainage of EDI treated water):
ET concentration in the water storage tank 2: 590 EU / L
ET concentration in EDI treated water: 539 EU / L

DESCRIPTION OF SYMBOLS 1 RO processing apparatus 2 Storage tank 3 EDI apparatus 4 RO pump 5 EDI supply pump 11 Raw water (tap water) supply line 12 1st line 13 2nd line 14 3rd line 15 Purified water intake line 16 Washing water drain line 21 , 22 Open / close valve

The If you stop the production run (if EDI apparatus is de-energized from energized state), the relation of the suction force> desorption force, in order to change the relationship between the attractive force <desorption force, the desalting compartment The adsorbed and retained ET, microorganisms, and impurities derived from the microorganisms are considered to be desorbed and easily released into EDI-treated water.

Claims (10)

A purified water production method using a purified water production apparatus having a reverse osmosis membrane treatment apparatus (hereinafter referred to as “RO treatment apparatus”), a water storage tank, and an electric regeneration type deionization apparatus (hereinafter referred to as “EDI apparatus”). ,
The method for producing purified water is a method comprising a combination of a purified water production process and a washing process,
The manufacturing apparatus can store treated water from the RO treatment apparatus (hereinafter referred to as “RO treated water”) in the water storage tank, and supplies the treated water stored in the water storage tank to the EDI apparatus. (Hereinafter referred to as “EDI treated water”)
The first line that sends the RO treated water from the RO treatment device to the water storage tank, the second line that sends the water in the water storage tank to the EDI device, and the EDI treated water is returned to the water storage tank that stores the RO treated water from the EDI device. And a third drain line connected to a third drain line for draining flush water.
The purified water production process comprises:
A first step of storing the RO treated water obtained by the RO treatment device by sending it from the first line to the water storage tank;
The RO treatment water stored in the water storage tank is sent from the second line to the EDI device for processing, and has a second step of obtaining EDI treated water,
Further, a part or all of the EDI treated water is returned from the third line to the water storage tank, and the third step is a step having a third step of obtaining a mixed water of the RO treated water and the EDI treated water.
The washing step
In the state where the operation of the EDI device is stopped (non-energized state), it is adsorbed to the ion exchanger by washing the RO-treated water through at least the desalting chamber filled with the ion exchanger in the EDI device. A method for producing purified water, which is a step of desorbing endotoxin and microorganisms that have been removed, and discharging cleaning wastewater containing the endotoxin and microorganisms from a drain line for cleaning water. A purified water production method using a purified water production apparatus having a reverse osmosis membrane treatment apparatus (hereinafter referred to as “RO treatment apparatus”), a water storage tank, and an electric regeneration type deionization apparatus (hereinafter referred to as “EDI apparatus”). ,
The method for producing purified water is a method comprising a combination of a purified water production process and a washing process,
The manufacturing apparatus can store treated water from the RO treatment apparatus (hereinafter referred to as “RO treated water”) in the water storage tank, and supplies the treated water stored in the water storage tank to the EDI apparatus. (Hereinafter referred to as “EDI treated water”)
The first line that sends the RO treated water from the RO treatment device to the water storage tank, the second line that sends the water in the water storage tank to the EDI device, and the EDI treated water is returned to the water storage tank that stores the RO treated water from the EDI device. A circulation line is formed by combining water supply from the EDI device to the water storage tank using the third line and water supply from the water storage tank to the EDI device using the second line,
Furthermore, a drain line for washing water for draining washing water is connected to the third line,
The purified water production process comprises:
A first step of storing the RO treated water obtained by the RO treatment device by sending it from the first line to the water storage tank;
The RO treatment water stored in the water storage tank is sent from the second line to the EDI device for processing, and has a second step of obtaining EDI treated water,
Further, part or all of the EDI treated water is returned from the third line to the water storage tank to obtain a mixed water of the RO treated water and the EDI treated water, and the mixed water is again sent from the second line to the EDI apparatus. It is a step having a circulation step that repeats the fourth step to send and process,
The washing step
In the state where the operation of the EDI device is stopped (non-energized state), it is adsorbed to the ion exchanger by washing the RO-treated water through at least the desalting chamber filled with the ion exchanger in the EDI device. A method for producing purified water, which is a step of desorbing endotoxin and microorganisms that have been removed, and discharging cleaning wastewater containing the endotoxin and microorganisms from a drain line for cleaning water.   The purified water according to claim 1 or 2, wherein, in the washing step, the RO treated water is passed at a flow rate of 3 to 15 L / min for 5 minutes or more per 1 L of the volume of the desalting chamber filled with the ion exchanger. Manufacturing method.   The purification according to any one of claims 1 to 3, wherein the washing step is performed at least once selected from a desired point in the course of production of purified water, after completion of production of purified water, and before production of purified water. Water production method. During the circulation process, the third process of returning EDI treated water to the water storage tank
A total amount circulation step for returning the total amount of EDI treated water from when the EDI treated water is first returned to the water storage tank after the operation is started until the total amount returned is at least equal to the average amount of water in the water storage tank;
After that, the manufacturing method of the purified water of any one of Claims 2-4 which has a partial amount circulation process which returns and circulates 10-80% of EDI treated water. The ratio (V ₁ / V ₂ ) between the amount of EDI treated water per hour (V ₁ ) (L) by the EDI device and the average amount of water (V ₂ ) (L) in the water storage tank is 2-12 The manufacturing method of the purified water of any one of Claims 2-5 which drive | operates.   The total amount circulation process returns the total amount of EDI treated water from when the EDI treated water was first returned to the storage tank after the start of operation until the total amount returned was the same amount to four times the average amount of water in the storage tank. The manufacturing method of the purified water of any one of Claims 2-6 which is a process to perform.   The method for producing purified water according to any one of claims 2 to 7, wherein the partial amount circulation step is a step of returning and circulating a 10 to 60% amount of EDI treated water.   The method for producing purified water according to any one of claims 1 to 8, wherein the purified water is continuously produced while being supplied as purified water. It has a reverse osmosis membrane treatment device (hereinafter referred to as “RO treatment device”), a water storage tank, and an electric regeneration type deionization device (hereinafter referred to as “EDI device”).
Treated water from the RO treatment device (hereinafter referred to as “RO treated water”) can be stored in the water storage tank, the treated water stored in the water storage tank is supplied to the EDI device, and treated water (hereinafter referred to as “EDI treated water”). An apparatus for producing purified water,
The first line that sends the RO treated water from the RO treatment device to the water storage tank, the second line that sends the water in the water storage tank to the EDI device, and the EDI treated water is returned to the water storage tank that stores the RO treated water from the EDI device. A circulation line is formed by combining water supply from the EDI device to the water storage tank using the third line and water supply from the water storage tank to the EDI device using the second line,
Furthermore, a drain line for washing water for discharging washing water is connected to the third line,
The ratio (V ₁ / V ₃ ) of the amount of EDI treated water per hour (V ₁ ) (L) by the EDI device and the capacity (V ₃ ) (L) of the water storage tank is 1.5 to 10, Purified water production equipment.

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