JP2000061464A - Pure water production method - Google Patents
Pure water production methodInfo
- Publication number
- JP2000061464A JP2000061464A JP10230718A JP23071898A JP2000061464A JP 2000061464 A JP2000061464 A JP 2000061464A JP 10230718 A JP10230718 A JP 10230718A JP 23071898 A JP23071898 A JP 23071898A JP 2000061464 A JP2000061464 A JP 2000061464A
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- Prior art keywords
- water
- reverse osmosis
- osmosis membrane
- membrane
- concentrated
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- Physical Water Treatments (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
(57)【要約】
【課題】 イオン交換設備を用いることなく、比抵抗１
５ＭΩ・ｃｍ以上の高水質の純水を高い水回収率で得
る。
【解決手段】 ３段に直列配置されたＲＯ装置３，４，
５に順次通水して純水を製造するに当り、第１ＲＯ装置
３の濃縮水を第４ＲＯ装置６でＲＯ処理し、その透過水
を第２，第３ＲＯ装置４，５の濃縮水と共に脱気処理し
て第１ＲＯ装置３の給水とする。
(57) [Summary] [Problem] Specific resistance 1 without using ion exchange equipment
Pure water of high water quality of 5 MΩ · cm or more is obtained at a high water recovery rate. SOLUTION: RO devices 3, 4 arranged in series in three stages.
5 to produce pure water, the concentrated water of the first RO device 3 is subjected to RO treatment in the fourth RO device 6, and the permeated water is removed together with the concentrated water of the second and third RO devices 4 and 5. The first RO device 3 is supplied with water.
Description
【０００１】[0001]
【発明の属する技術分野】本発明は純水の製造方法に係
り、特に原水を脱気した後、３段逆浸透膜（ＲＯ膜）分
離処理して高水質の純水を高回収率で製造する方法に関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing pure water, and in particular, after degassing raw water, a three-stage reverse osmosis membrane (RO membrane) separation treatment is performed to produce pure water of high water quality with a high recovery rate. On how to do.
【０００２】[0002]
【従来の技術】半導体製造工程等で使用される純水を、
主に原水のＲＯ処理を行って製造する方法として、従
来、次のような方法が提案されている。2. Description of the Related Art Pure water used in semiconductor manufacturing processes,
Conventionally, the following method has been proposed as a method for producing mainly by subjecting raw water to RO treatment.
【０００３】 市水等の原水に酸を添加して炭酸イオ
ン分解（ＣＯ2化）した水を膜脱気装置で脱気処理した
後、２段に直列配置したＲＯ膜分離装置に順次通水して
２段ＲＯ処理する方法（特公平８−２９３１５号公報）
原水を３段に直列配置したＲＯ膜分離装置に順次通
水して３段ＲＯ処理する方法であって、１段目のＲＯ処
理水にアルカリを添加して２段目のＲＯ膜分離装置に供
給する方法（特開平７−１６５６５号公報）
原水を２段に直列配置したＲＯ膜分離装置に順次通
水して２段ＲＯ処理する方法であって、酸性条件の原水
を１段目のＲＯ膜分離装置に通水し、１段目のＲＯ処理
水にアルカリを添加した後２段目のＲＯ膜分離装置に通
水し、２段目のＲＯ膜分離装置の濃縮水を１段目のＲＯ
膜分離装置の給水側に返送して水回収率を高める方法
（特公昭６２−４３７８７号公報）Water obtained by adding an acid to raw water such as city water to decompose carbonate ions (CO 2 conversion) is degassed by a membrane degassing device, and then sequentially passed through RO membrane separation devices arranged in series in two stages. Method for performing two-stage RO treatment (Japanese Patent Publication No. 8-29315) A method for performing three-stage RO treatment by successively passing raw water through an RO membrane separation device in which three stages are arranged in series. Method of adding alkali to treated water and supplying it to the second-stage RO membrane separation device (Japanese Patent Laid-Open No. 7-16565) Raw water is sequentially passed through the two-stage RO membrane separation device to sequentially pass the second-stage RO membrane separation device In this method, raw water under acidic conditions is passed through the first stage RO membrane separator, alkali is added to the first stage RO treated water, and then water is passed through the second stage RO membrane separator. Concentrated water from the second-stage RO membrane separator is used as the first-stage RO
Method of increasing the water recovery rate by returning to the water supply side of the membrane separator (Japanese Patent Publication No. 62-43787)
【０００４】[0004]
【発明が解決しようとする課題】上記従来の純水の製造
方法では、十分に純度の高い純水を得ることはできな
い。このため、半導体製造工程等で必要とされる比抵抗
１０ＭΩ・ｃｍ以上の水質の純水を得るためには、更に
後段に非再生型イオン交換装置等を設けて処理する必要
があるが、この場合には、後段のイオン交換装置の負荷
が過大となることから、イオン交換装置として非再生型
のものを用いた場合には、数ケ月程度で交換する必要が
あり、メンテナンス作業が著しく手間のかかるものとな
る。With the above-mentioned conventional method for producing pure water, pure water having a sufficiently high purity cannot be obtained. Therefore, in order to obtain pure water of a water quality having a specific resistance of 10 MΩ · cm or more, which is required in a semiconductor manufacturing process or the like, it is necessary to further provide a non-regeneration type ion exchange device or the like at a subsequent stage for treatment. In this case, since the load on the ion exchange device in the subsequent stage becomes excessive, if a non-regenerative ion exchange device is used, it needs to be replaced in about several months, and maintenance work is extremely troublesome. It becomes such a thing.
【０００５】また、特にの方法では１段目のＲＯ処理
を酸性条件で行うため、この１段目のＲＯ膜分離装置で
炭酸成分を殆ど除去することができず、この炭酸成分を
アルカリ条件の２段目のＲＯ膜分離装置で除去すること
から、１段目のＲＯ膜分離装置には炭酸成分が濃縮さ
れ、返送水として不適当な２段目ＲＯ膜分離装置の濃縮
水が返送されるという欠点もある。Further, in the particular method, since the first-stage RO treatment is carried out under acidic conditions, almost no carbonic acid component can be removed by this first-stage RO membrane separator, and this carbonic acid component is treated under alkaline conditions. Since it is removed by the second-stage RO membrane separation device, the carbonic acid component is concentrated in the first-stage RO membrane separation device, and the concentrated water of the second-stage RO membrane separation device that is inappropriate as return water is returned. There is also a drawback.
【０００６】本発明は上記従来の問題点を解決し、イオ
ン交換装置を用いることなくＲＯ処理により比抵抗１５
ＭΩ・ｃｍ以上の高水質の純水を、高い水回収率で得る
ことができる純水の製造方法を提供することを目的とす
る。The present invention solves the above-mentioned conventional problems, and a specific resistance of 15 is obtained by RO treatment without using an ion exchange device.
It is an object of the present invention to provide a method for producing pure water, which can obtain high-quality pure water of MΩ · cm or more with a high water recovery rate.
【０００７】[0007]
【課題を解決するための手段】本発明の純水の製造方法
は、原水を３段に直列配置された第１段目、第２段目及
び第３段目の逆浸透膜分離装置に順次通水して純水を製
造する方法において、第１段目の逆浸透膜分離装置の濃
縮水を第４の逆浸透膜分離装置に通水して透過水を得、
該透過水を第２段目の逆浸透膜分離装置の濃縮水及び第
３段目の逆浸透膜分離装置の濃縮水と共に脱気処理した
後、第１段目の逆浸透膜分離装置に給水することを特徴
とする。According to the method for producing pure water of the present invention, raw water is sequentially applied to first, second and third reverse osmosis membrane separation devices in which three stages of raw water are arranged in series. In the method for producing pure water by passing water, the concentrated water of the first-stage reverse osmosis membrane separation device is passed through the fourth reverse osmosis membrane separation device to obtain permeated water,
The permeated water is deaerated together with the concentrated water of the second-stage reverse osmosis membrane separator and the concentrated water of the third-stage reverse osmosis membrane separator, and then supplied to the first-stage reverse osmosis membrane separator. It is characterized by doing.
【０００８】本発明においては、好ましくは、活性炭処
理等の前処理を行った原水をｐＨ６以下に調整して脱気
処理した後第１段目の逆浸透膜分離装置（第１ＲＯ装
置）に通水し、第１ＲＯ装置の透過水にアルカリを添加
してアルカリ条件とした後第２段目の逆浸透膜分離装置
（第２ＲＯ装置）及び第３段目の逆浸透膜分離装置（第
３ＲＯ装置）に順次通水する。In the present invention, it is preferable that the raw water that has been subjected to pretreatment such as activated carbon treatment is adjusted to pH 6 or less and deaerated, and then passed through the first-stage reverse osmosis membrane separation device (first RO device). After watering and adding alkali to the permeated water of the first RO device to make the conditions alkaline, a second-stage reverse osmosis membrane separation device (second RO device) and a third-stage reverse osmosis membrane separation device (third RO device) ).
【０００９】原水をｐＨ６以下に調整した後脱気処理す
ることにより、原水中に含まれる、ＲＯ処理では除去し
難い炭酸成分をＣＯ2の形態として効率的に除去するこ
とができる。By adjusting the pH of the raw water to 6 or less and then degassing it, the carbonic acid component contained in the raw water, which is difficult to remove by the RO treatment, can be efficiently removed in the form of CO 2 .
【００１０】脱気処理水を第１ＲＯ装置に給水する場
合、この脱気処理水は酸性であるため、第１ＲＯ装置の
ＲＯ膜へシリカやカルシウム、アルミニウム等のスケー
ルが析出し難く、安定運転のために有利である。また、
この第１ＲＯ装置の流入水が酸性であることにより、ア
ンモニアの除去が効率的に行われる。ただし、前段の脱
気処理で残存した炭酸の除去率は酸性条件であるため低
い。When the degassed water is supplied to the first RO apparatus, since the degassed water is acidic, scales of silica, calcium, aluminum, etc. do not easily deposit on the RO membrane of the first RO apparatus, and stable operation is ensured. Is advantageous for. Also,
Since the inflow water of the first RO device is acidic, ammonia can be removed efficiently. However, the removal rate of carbonic acid remaining in the degassing treatment in the first stage is low because of the acidic conditions.
【００１１】この第１ＲＯ装置の透過水にアルカリを添
加してアルカリ性とし、第２ＲＯ装置及び第３ＲＯ装置
に順次通水して処理することにより、イオン交換装置を
用いることなく、比抵抗１５ＭΩ・ｃｍ以上の高水質の
純水を得ることができる。Alkali is added to the permeated water of the first RO device to make it alkaline, and water is sequentially passed through the second RO device and the third RO device to be treated, whereby the specific resistance is 15 MΩ · cm without using an ion exchange device. It is possible to obtain pure water of high quality as described above.
【００１２】ところで、第１ＲＯ装置の濃縮水は、イオ
ン濃度が高いため第１ＲＯ装置の給水として返送するこ
とは不適当であるが、これを第４のＲＯ装置でＲＯ処理
して得られる透過水であればイオン濃度が低減されてい
るため第１ＲＯ装置の給水として返送することができ、
このように第１ＲＯ装置の濃縮水の一部を返送すること
により、水の利用効率を高め、水回収率を高めることが
できる。なお、第１ＲＯ装置の給水は酸性の水であるた
め、第１ＲＯ装置の濃縮水も酸性であり、これをＲＯ処
理して得られる透過水も酸性となる。By the way, the concentrated water of the first RO device is unsuitable to be returned as the feed water of the first RO device because of its high ion concentration, but the permeated water obtained by RO treatment of this in the fourth RO device If so, since the ion concentration is reduced, it can be returned as water supply for the first RO device,
By returning a part of the concentrated water of the first RO device in this manner, it is possible to improve the water utilization efficiency and the water recovery rate. Since the feed water of the first RO device is acidic water, the concentrated water of the first RO device is also acidic, and the permeated water obtained by subjecting this to RO treatment is also acidic.
【００１３】一方、第２，第３ＲＯ装置の濃縮水はアル
カリ性であり、このアルカリ性の第２，第３ＲＯ装置の
濃縮水には、イオン形態の炭酸成分が濃縮されている。
この第２，第３ＲＯ装置の濃縮水を、酸性の第４ＲＯ装
置透過水と混合すると、混合水は酸性となり、炭酸成分
はＣＯ2の形態となる。従って、この混合水を脱気処理
することにより、該混合水中の炭酸成分を効率的に除去
することができ、第１ＲＯ装置に給水する返送水として
適した水質とすることができる。また、水を循環処理す
ることによる系内の炭酸成分の蓄積が防止される。On the other hand, the concentrated water of the second and third RO devices is alkaline, and the alkaline concentrated water of the second and third RO devices is concentrated with an ionic carbonate component.
When the concentrated water of the second and third RO devices is mixed with the acidic permeated water of the fourth RO device, the mixed water becomes acidic and the carbonic acid component is in the form of CO 2 . Therefore, by degassing the mixed water, the carbonic acid component in the mixed water can be efficiently removed, and the water quality suitable for the return water to be supplied to the first RO device can be obtained. Moreover, the accumulation of carbonic acid components in the system due to the circulating treatment of water is prevented.
【００１４】本発明において、原水の脱気処理、及び、
第４ＲＯ装置透過水と第２，第３ＲＯ装置の濃縮水との
混合水の脱気処理は、膜脱気により行うのが好ましい。In the present invention, deaeration of raw water, and
The degassing treatment of the mixed water of the permeated water of the fourth RO device and the concentrated water of the second and third RO devices is preferably performed by membrane degassing.
【００１５】なお、第３ＲＯ装置に流入する第２ＲＯ装
置の透過水は、塩類濃度が十分に低減されているので、
第３ＲＯ装置のＲＯ膜としては低塩類濃度域における塩
類阻止率の高い正荷電膜を用いるのが好ましい。即ち、
ＲＯ膜の塩類阻止率は、原水中の塩類濃度が低くなるに
つれて低下する傾向があるが、第３ＲＯ装置のＲＯ膜と
して正荷電膜を用いることにより、第３ＲＯ装置におい
ても著しく高いＲＯ処理効果を得ることができ、きわめ
て高水質の純水を製造することが可能となる。Since the salt concentration of the permeated water of the second RO device flowing into the third RO device is sufficiently reduced,
As the RO film of the third RO device, it is preferable to use a positively charged film having a high salt rejection rate in a low salt concentration range. That is,
The salt rejection of the RO membrane tends to decrease as the salt concentration in the raw water decreases, but by using a positively charged membrane as the RO membrane of the third RO device, a significantly high RO treatment effect can be obtained in the third RO device as well. It is possible to obtain pure water of extremely high quality.
【００１６】[0016]
【発明の実施の形態】以下に、図面を参照して本発明の
実施の形態を説明する。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.
【００１７】図１は本発明の純水の製造方法の実施の形
態を示す系統図である。FIG. 1 is a system diagram showing an embodiment of a method for producing pure water according to the present invention.
【００１８】本実施の形態においては、市水、井水、工
業用水等を原水として、必要に応じて凝集沈澱、膜濾
過、活性炭処理等の前処理を施した後（図１では活性炭
塔１に通水した後）、ＨＣｌ，Ｈ2ＳＯ4等の酸を添加し
て原水中のＭ−アルカリ成分の主体をなすＨＣＯ3 -，Ｃ
Ｏ3 2-イオンを脱気装置で除去し易いＣＯ2の形態とす
る。この酸性水を膜脱気装置、真空脱気装置、窒素脱気
装置、脱炭酸塔等の脱気装置２（好ましくは膜脱気装
置）に通水する。なお、酸の添加量は、脱気処理される
水のｐＨが６以下、好ましくは５以下、特に３〜５程度
となるような量とするのが好ましい。例えば、膜脱気装
置を用い、ｐＨ４．５の条件で脱気処理した場合には、
炭酸除去率を９５％以上に高めることができる。In the present embodiment, city water, well water, industrial water, etc. are used as raw water, and if necessary, after pretreatment such as coagulation sedimentation, membrane filtration, activated carbon treatment (in FIG. 1, activated carbon tower 1 after passed through) to, HCl, HCO 3 forming a main body of the H 2 SO 4 M- alkali component acid to the raw water added such -, C
The form of CO 2 is used so that O 3 2− ions can be easily removed by a deaerator. This acidic water is passed through a deaerator 2 (preferably a membrane deaerator) such as a membrane deaerator, a vacuum deaerator, a nitrogen deaerator, and a decarbonation tower. The acid is preferably added in such an amount that the pH of the water to be degassed is 6 or less, preferably 5 or less, and particularly about 3 to 5. For example, when using a membrane degasser and degassing under the condition of pH 4.5,
The carbon dioxide removal rate can be increased to 95% or more.
【００１９】脱気装置２では、原水中のＣＯ2を気相に
移行させて除去すると共に原水中の溶存酸素も気相に移
行させて除去する。In the deaerator 2, CO 2 in the raw water is transferred to the gas phase to be removed, and also dissolved oxygen in the raw water is transferred to the gas phase to be removed.
【００２０】脱気処理水は、第１ＲＯ装置３に導入して
ＲＯ処理する。この第１ＲＯ装置３では、原水に添加し
た酸により調整された低ｐＨ条件下において、主にＮａ
+イオンやアンモニア等のカチオン成分を除去する。The degassed treated water is introduced into the first RO device 3 for RO treatment. In this first RO device 3, under the low pH condition adjusted by the acid added to the raw water, mainly Na
+ Removes cation components such as ions and ammonia.
【００２１】即ち、一般にＲＯ膜処理においては、Ｎａ
+イオン等のカチオン成分はｐＨ３〜５の低ｐＨ領域で
高い除去率を示し、逆にＣｌ-イオン等のアニオン成分
はｐＨ５．５以上で高い除去率を示すため、第１ＲＯ装
置３では低ｐＨの脱気処理水について主にカチオン成分
の除去を行う。That is, in general, in the RO membrane treatment, Na
Cation components such as + ions show a high removal rate in the low pH region of pH 3 to 5, and anion components such as Cl − ions show a high removal rate at a pH of 5.5 or higher, so that the first RO device 3 has a low pH. The decationized water of (1) is mainly used to remove cation components.
【００２２】なお、この第１ＲＯ装置３のＲＯ処理はｐ
Ｈ３〜５の範囲で行うのが好ましい。従って、脱気処理
水のｐＨがこの範囲よりも高い場合には脱気処理水に更
に酸を添加してｐＨ調整を行ってから第１ＲＯ装置３に
流入させるのが好ましい。The RO process of the first RO device 3 is p
It is preferable to carry out in the range of H3 to H5. Therefore, when the pH of the degassed water is higher than this range, it is preferable to add an acid to the degassed water to adjust the pH and then to flow into the first RO apparatus 3.
【００２３】第１ＲＯ装置の透過水は、次いで、ＮａＯ
Ｈ等のアルカリを添加してｐＨ６．５〜８、例えばｐＨ
７．５程度に調整した後、第２ＲＯ装置４に導入してＲ
Ｏ処理する。この第２ＲＯ装置４の入口側でのｐＨ調整
は、得られる処理水（第３ＲＯ装置５の透過水）の比抵
抗が十分に低くなるように設定すれば良く、例えば、第
３ＲＯ装置５の透過水の比抵抗を測定し、この測定値に
基いて最適ｐＨ設定値をフィードバック制御にて調整す
るようにするのが好ましい。The permeate of the first RO device is then NaO
Add an alkali such as H to obtain a pH of 6.5 to 8, for example, pH
After adjusting to about 7.5, it is introduced into the second RO device 4 and R
O treatment. The pH adjustment on the inlet side of the second RO device 4 may be set so that the specific resistance of the obtained treated water (permeated water of the third RO device 5) is sufficiently low. It is preferable to measure the specific resistance of water and adjust the optimum pH set value by feedback control based on this measured value.
【００２４】第２ＲＯ装置４の透過水の水質は比抵抗で
数ＭΩ・ｃｍから最高でも６〜７ＭΩ・ｃｍ程度である
ため、本発明では、更に水質を向上させるために、第２
ＲＯ装置４の透過水を第３ＲＯ装置５に導入してＲＯ処
理する。この第３ＲＯ装置５の透過水は処理水として系
外へ取り出される。Since the water quality of the permeated water of the second RO device 4 is from several MΩ · cm to 6 to 7 MΩ · cm at the maximum in the specific resistance, in the present invention, in order to further improve the water quality,
The permeated water of the RO device 4 is introduced into the third RO device 5 to perform RO treatment. The permeated water of the third RO device 5 is taken out of the system as treated water.
【００２５】本発明では、このような３段ＲＯ処理にお
いて、第１ＲＯ装置３の濃縮水を第４ＲＯ装置６でＲＯ
処理し、得られた透過水を第２，第３ＲＯ装置４，５の
濃縮水と共に脱気装置７で脱気処理した後、第１ＲＯ装
置３の給水として再利用する。この脱気装置７としても
膜脱気装置を用いるのが好ましく、膜脱気により効率的
な脱気処理を行える。なお、第４ＲＯ装置の濃縮水は系
外に排出される。In the present invention, in such a three-stage RO treatment, the concentrated water of the first RO device 3 is RO-treated by the fourth RO device 6.
The permeated water obtained by the treatment is deaerated by the deaerator 7 together with the concentrated water of the second and third RO apparatuses 4 and 5, and then reused as the water supply for the first RO apparatus 3. It is preferable to use a membrane degassing device also as the degassing device 7, and efficient degassing treatment can be performed by the film degassing. The concentrated water of the fourth RO device is discharged out of the system.
【００２６】なお、本発明において、第１，第２ＲＯ装
置３，４のＲＯ膜として日東電工社製「ＥＳ２０」、東
レ株式会社製「ＳＵ７１０」等の負荷電膜を用いること
ができる。In the present invention, as the RO film of the first and second RO devices 3 and 4, a negative electrode film such as "ES20" manufactured by Nitto Denko Corporation and "SU710" manufactured by Toray Industries, Inc. can be used.
【００２７】また、第３ＲＯ装置５のＲＯ膜としては、
前述の如く、低塩類濃度域における塩類阻止率の高い正
荷電膜、例えば、塩類濃度１〜１０ｐｐｍというような
低塩類濃度域における塩類阻止率が９９％以上のＲＯ
膜、具体的には、日東電工社製「ＮＴＲ−７１９Ｈ
Ｆ」，「ＥＳ１０Ｃ」、東レ株式会社製「ＳＵ９００」
（いずれもＮａＣｌ濃度１〜１０ｐｐｍでのＮａＣｌ阻
止率９９％以上）等の正荷電膜を用いるのが好ましい。Further, as the RO film of the third RO device 5,
As described above, a positively charged film having a high salt rejection rate in a low salt concentration range, for example, an RO having a salt rejection rate of 99% or higher in a low salt concentration range of 1 to 10 ppm.
Membrane, specifically, "NTR-719H" manufactured by Nitto Denko Corporation
"F", "ES10C", "SU900" manufactured by Toray Industries, Inc.
It is preferable to use a positively charged film such as (99% or more of NaCl blocking rate at NaCl concentration of 1 to 10 ppm).
【００２８】第４ＲＯ装置６のＲＯ膜としては、日東電
工社製「Ｅ５２０」、東レ株式会社製「ＳＵ７１０」、
Ｆｉｌｍｔｅｃ社製「ＢＷ３０−４４０」等の負荷電膜
を用いるのが好ましい。As the RO film of the fourth RO device 6, "E520" manufactured by Nitto Denko Corporation, "SU710" manufactured by Toray Industries, Inc.,
It is preferable to use a negative electrode film such as "BW30-440" manufactured by Filmtec.
【００２９】なお、正荷電膜とは、限外濾過膜の上に界
面架橋のような方法で薄いスキン層を形成してなるＲＯ
複合膜のうち、カチオン基、例えば第四アンモニウム基
等を導入することにより、膜表面を正に帯電させたもの
であり、一方、負荷電膜とは、このようなＲＯ複合膜に
おいて、アニオン基、例えばカルボキシル基等を導入し
て膜表面を負に帯電させたものである。The positively charged membrane is an RO formed by forming a thin skin layer on the ultrafiltration membrane by a method such as interfacial crosslinking.
Among the composite membranes, the surface of the membrane is positively charged by introducing a cation group such as a quaternary ammonium group. On the other hand, the negatively charged membrane is an anionic group in such RO composite membrane. For example, the surface of the film is negatively charged by introducing a carboxyl group or the like.
【００３０】各ＲＯ装置の採水率については特に制限は
ないが、給水（１００％）に対して次のような範囲とす
るのが好ましい。The water sampling rate of each RO device is not particularly limited, but it is preferable to set the following range for water supply (100%).
【００３１】
また、本発明では、原水を脱気処理して伝導度３０〜１
２０μＳ・ｃｍ程度の脱気処理水を得、第１ＲＯ装置の
濃縮水のＲＯ透過水と第２，第３ＲＯ装置の濃縮水との
混合水を脱気処理して伝導度５〜３０μＳ・ｃｍ程度の
脱気処理水を得、これらを併せて第１ＲＯ装置の給水と
して供給するようにするのが好ましい。[0031] In the present invention, the raw water is degassed to have a conductivity of 30 to 1
Degassed water of about 20 μS · cm is obtained, and the mixed water of the RO permeated water of the first RO device and the concentrated water of the second and third RO devices is deaerated to have a conductivity of about 5 to 30 μS · cm. It is preferable to obtain the degassed treated water of 1. and to supply them together as the feed water for the first RO device.
【００３２】このような本発明の方法によれば、処理水
（第３ＲＯ装置の透過水）として、比抵抗１５ＭΩ・ｃ
ｍ以上の高水質の純水を得ることができる。従って、こ
の純水は更にイオン交換処理することなく使用すること
もでき、また、更にイオン交換処理する場合において
は、イオン交換装置の負荷を大幅に軽減することがで
き、非再生型イオン交換装置の場合、その寿命を６ケ月
〜１年以上に大幅に延長することができる。このため、
メンテナンス作業が大幅に軽減される。According to such a method of the present invention, the treated water (permeated water of the third RO device) has a specific resistance of 15 MΩ · c.
It is possible to obtain pure water having a high water quality of m or more. Therefore, this pure water can be used without further ion exchange treatment, and in the case of further ion exchange treatment, the load on the ion exchange device can be greatly reduced, and the non-regeneration type ion exchange device can be used. In the case of, the life can be extended significantly from 6 months to 1 year or more. For this reason,
Maintenance work is greatly reduced.
【００３３】しかも、第１ＲＯ装置の濃縮水をＲＯ処理
して得られる透過水及び第２，第３ＲＯ装置の濃縮水を
返送して再利用することにより、水回収率を大幅に高め
ることができる。Moreover, by returning the permeated water obtained by RO treatment of the concentrated water of the first RO device and the concentrated water of the second and third RO devices for reuse, the water recovery rate can be greatly increased. .
【００３４】[0034]
【実施例】以下に実施例を挙げて本発明をより具体的に
説明する。EXAMPLES The present invention will be described in more detail with reference to the following examples.
【００３５】実施例１
図１に示す本発明の方法により、半導体工場の回収水と
市水を混合した水を原水として純水の製造を行った。Example 1 By the method of the present invention shown in FIG. 1, pure water was produced by using water obtained by mixing recovered water of a semiconductor factory and city water as raw water.
【００３６】まず、原水を活性炭塔１に通水後、ＨＣｌ
を添加してｐＨ４．５に調整して膜脱気装置（脱気膜：
ポリプロピレン膜）２に通水して脱気処理した後第１Ｒ
Ｏ装置３に通水した。そして、この第１ＲＯ装置３の透
過水にＮａＯＨを添加してｐＨ７．５とし、第２，第３
ＲＯ装置４，５に通水した。First, after passing raw water through the activated carbon tower 1, HCl
Is added to adjust the pH to 4.5 and the membrane degassing device (degassing membrane:
After passing through polypropylene film 2 and degassing, the first R
Water was passed through the O device 3. Then, NaOH is added to the permeated water of the first RO device 3 to adjust the pH to 7.5, and the second and third
Water was passed through the RO devices 4 and 5.
【００３７】第１ＲＯ装置３の濃縮水は第４ＲＯ装置６
でＲＯ処理し、濃縮水は系外へ排出した。第４ＲＯ装置
６の透過水と第２，第３ＲＯ装置４，５の濃縮水とを合
流させて膜脱気装置（脱気膜：ポリプロピレン膜）７に
通水して脱気処理し、第１ＲＯ装置３の給水とした。The concentrated water of the first RO device 3 is the fourth RO device 6
RO treatment was carried out, and the concentrated water was discharged out of the system. The permeated water of the fourth RO device 6 and the concentrated water of the second and third RO devices 4, 5 are merged and passed through a membrane deaeration device (deaeration membrane: polypropylene membrane) 7 for deaeration treatment, and the first RO The water was supplied to the device 3.
【００３８】なお、各ＲＯ装置３，４，５，６で用いた
ＲＯ膜及び給水、透過水及び濃縮水量は次の通りであ
る。The RO membrane used in each RO device 3, 4, 5, 6 and the amount of feed water, permeated water and concentrated water are as follows.
【００３９】第１ＲＯ装置３：
ＲＯ膜＝日東電工社製「ＥＳ２０」（ポリアミド製）
給水量＝１１４．８ｍ3／ｈｒ
透過水量＝９１．９ｍ3／ｈｒ
濃縮水量＝２２．９ｍ3／ｈｒ
第２ＲＯ装置４：
ＲＯ膜＝日東電工社製「ＥＳ２０」（ポリアミド製）
給水量＝９１．９ｍ3／ｈｒ
透過水量＝７３．５ｍ3／ｈｒ
濃縮水量＝１８．４ｍ3／ｈｒ
第３ＲＯ装置５：
ＲＯ膜＝日東電工社製「ＥＳ１０Ｃ」（ポリアミド製）
給水量＝７３．５ｍ3／ｈｒ
透過水量＝５８．８ｍ3／ｈｒ
濃縮水量＝１４．７ｍ3／ｈｒ
第４ＲＯ装置６：
ＲＯ膜＝日東電工社製「ＥＳ２０」（ポリアミド製）
給水量＝２２．９ｍ3／ｈｒ
透過水量＝１８．３ｍ3／ｈｒ
濃縮水量＝４．６ｍ3／ｈｒ
原水を膜脱気装置２で脱気処理して得られた脱気処理
水、第１ＲＯ装置３の濃縮水のＲＯ透過水と第２，第３
ＲＯ装置４，５の濃縮水とを膜脱気装置７で脱気処理し
て得られた返送脱気処理水及び得られた処理水（第３Ｒ
Ｏ装置５の透過水）の水質を表１に示す。[0039] The 1RO device 3: RO membrane = (of polyamide) manufactured by Nitto Denko Corporation, "ES20" water supply amount = 114.8m 3 / hr permeated water = 91.9m 3 / hr concentrated water = 22.9 m 3 / hr the 2RO device 4: RO membrane = Nitto Denko Co., Ltd. "ES20" (manufactured by polyamide) water supply = 91.9m 3 / hr permeated water = 73.5m 3 / hr concentrated water = 18.4 3 / hr first 3RO device 5: RO membrane = "ES10C" manufactured by Nitto Denko (polyamide) Water supply amount = 73.5m 3 / hr Permeate water amount = 58.8m 3 / hr Concentrated water amount = 14.7m 3 / hr 4th RO device 6: RO membrane = Nitto DENKO Co. "ES20" (manufactured by polyamide) water supply = 22.9 m 3 / hr permeated water = 18.3 m 3 / hr concentrated water = 4.6 m 3 / hr raw water with a membrane degasifier 2 deaerated The degassed water obtained, RO permeate and second concentrated water of the RO unit 3, a third
Return degassed treated water obtained by degassing the concentrated water of the RO devices 4 and 5 with the membrane degassing device 7 and the obtained treated water (3R
Table 1 shows the water quality of the permeated water of the O apparatus 5.
【００４０】[0040]
【表１】 [Table 1]
【００４１】表１より明らかなように、返送脱気処理水
は原水を脱気処理した水よりも高水質であり、各ＲＯ装
置の濃縮水を再利用した上で比抵抗１５．５ＭΩ・ｃｍ
という極めて高水質の純水を得ることができた。As is clear from Table 1, the returned degassed water has a higher water quality than the water obtained by degassing the raw water, and the specific resistance of 15.5 MΩ · cm after reusing the concentrated water of each RO device.
It was possible to obtain pure water of extremely high quality.
【００４２】しかも、このように濃縮水を返送すること
で、水回収率を９２．７％とすることができ、濃縮水を
全く返送しない場合の水回収率５１．２％に比べて、水
の利用効率を大幅に高めることができた。Moreover, by returning the concentrated water in this way, the water recovery rate can be made 92.7%, which is higher than the water recovery rate of 51.2% when the concentrated water is not returned at all. We were able to greatly improve the utilization efficiency of.
【００４３】[0043]
【発明の効果】以上詳述した通り、本発明の純水の製造
方法によれば、イオン交換設備を用いることなく、比抵
抗１５ＭΩ・ｃｍ以上の高水質の純水を高い水回収率で
得ることができる。As described in detail above, according to the method for producing pure water of the present invention, pure water of high water quality having a specific resistance of 15 MΩ · cm or more can be obtained at a high water recovery rate without using ion exchange equipment. be able to.
【図１】本発明の純水の製造方法の実施の形態を示す系
統図である。FIG. 1 is a system diagram showing an embodiment of a method for producing pure water according to the present invention.
１ 活性炭塔 ２ 脱気装置 ３ 第１ＲＯ装置 ４ 第２ＲＯ装置 ５ 第３ＲＯ装置 ６ 第４ＲＯ装置 ７ 脱気装置 1 activated carbon tower 2 deaerator 3 First RO device 4 Second RO device 5 Third RO device 6 Fourth RO device 7 Deaerator
Claims (5)
第２段目及び第３段目の逆浸透膜分離装置に順次通水し
て純水を製造する方法において、 第１段目の逆浸透膜分離装置の濃縮水を第４の逆浸透膜
分離装置に通水して透過水を得、該透過水を第２段目の
逆浸透膜分離装置の濃縮水及び第３段目の逆浸透膜分離
装置の濃縮水と共に脱気処理した後、第１段目の逆浸透
膜分離装置に給水することを特徴とする純水の製造方
法。1. A first stage in which raw water is arranged in three stages in series,
In the method for producing pure water by sequentially passing water through the second- and third-stage reverse osmosis membrane separators, the concentrated water of the first-stage reverse osmosis membrane separator is combined with the fourth reverse osmosis membrane separator. After passing through the device to obtain permeated water, the permeated water is deaerated together with the concentrated water of the second-stage reverse osmosis membrane separation device and the concentrated water of the third-stage reverse osmosis membrane separation device, A method for producing pure water, which comprises supplying water to a first-stage reverse osmosis membrane separation device.
以下に調整して脱気処理した後、第１段目の逆浸透膜分
離装置に通水することを特徴とする純水の製造方法。2. The method according to claim 1, wherein the raw water is adjusted to pH 6
A method for producing pure water, characterized in that the water is passed through a first-stage reverse osmosis membrane separation device after being adjusted and deaerated as described below.
分離装置の透過水にアルカリを添加して第２段目の逆浸
透膜分離装置に通水することを特徴とする純水の製造方
法。3. The pure water according to claim 2, wherein alkali is added to the permeated water of the first-stage reverse osmosis membrane separation device to pass the water through the second-stage reverse osmosis membrane separation device. Manufacturing method.
気処理及び前記透過水及び濃縮水の脱気処理を膜脱気に
より行うことを特徴とする純水の製造方法。4. The method for producing pure water according to claim 2, wherein the deaeration treatment of the raw water and the deaeration treatment of the permeated water and the concentrated water are performed by membrane degassing.
て、第３段目の逆浸透膜分離装置の逆浸透膜が正荷電膜
であることを特徴とする純水の製造方法。5. The method for producing pure water according to claim 1, wherein the reverse osmosis membrane of the third-stage reverse osmosis membrane separation device is a positively charged membrane.
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