JP3491268B2 - Desalination method and device using reverse osmosis membrane - Google Patents

Desalination method and device using reverse osmosis membrane

Info

Publication number
JP3491268B2
JP3491268B2 JP13068596A JP13068596A JP3491268B2 JP 3491268 B2 JP3491268 B2 JP 3491268B2 JP 13068596 A JP13068596 A JP 13068596A JP 13068596 A JP13068596 A JP 13068596A JP 3491268 B2 JP3491268 B2 JP 3491268B2
Authority
JP
Japan
Prior art keywords
reverse osmosis
water
osmosis membrane
treated
dissolved oxygen
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
JP13068596A
Other languages
Japanese (ja)
Other versions
JPH09290259A (en
Inventor
省三 梶尾
芳男 染谷
敏行 岡田
良明 村上
和孝 下坂
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Organo Corp
Original Assignee
Organo Corp
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Filing date
Publication date
Application filed by Organo Corp filed Critical Organo Corp
Priority to JP13068596A priority Critical patent/JP3491268B2/en
Publication of JPH09290259A publication Critical patent/JPH09290259A/en
Application granted granted Critical
Publication of JP3491268B2 publication Critical patent/JP3491268B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02ATECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A20/00Water conservation; Efficient water supply; Efficient water use
    • Y02A20/124Water desalination
    • Y02A20/131Reverse-osmosis

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【発明の属する技術分野】本発明は、逆浸透膜を用いた
脱塩処理方法及びその装置に関し、更に詳しくは、逆浸
透膜の酸化劣化を防止することができる逆浸透膜を用い
た脱塩処理方法及びその装置に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a desalination treatment method using a reverse osmosis membrane and an apparatus therefor, and more specifically to a desalination treatment using a reverse osmosis membrane capable of preventing oxidative deterioration of the reverse osmosis membrane. The present invention relates to a processing method and an apparatus thereof.

【0002】[0002]

【従来の技術】従来から、塩類を含有する被処理水(原
水)を脱塩処理する場合に逆浸透膜モジュールが広く用
いられている。ところが、原水中にはバクテリア等の微
生物や金属酸化物等の懸濁物質等、逆浸透膜に悪影響を
及ぼす有害物質が含まれているため、原水を逆浸透膜モ
ジュールに供給する前に、原水の前処理を行って有害物
質を除去している。具体的には、例えば原水に電解塩
素、次亜塩素酸ナトリウム等を添加して微生物を殺菌
し、更にその原水を濾過して懸濁物質を除去するなどの
処理を行っている。この前処理水には殺菌用として用い
た塩素が残留し、この残留塩素が逆浸透膜モジュールを
酸化劣化させるため、前処理水を逆浸透膜モジュールに
供給する前に、前処理水に還元剤として重亜硫酸ナトリ
ウムを例えば1〜10ppm添加して残留塩素を除去
し、逆浸透膜モジュールの酸化劣化を防止している。ま
た、前処理水には溶存酸素が存在し、溶存酸素が逆浸透
膜モジュールを酸化劣化するため、現在では溶存酸素に
強い材質(例えば、架橋全芳香族ポリアミド)を逆浸透
膜モジュールに使用し、溶存酸素による酸化劣化を防止
している。
2. Description of the Related Art Conventionally, a reverse osmosis membrane module has been widely used for desalination of treated water (raw water) containing salts. However, since raw water contains harmful substances that adversely affect the reverse osmosis membrane, such as microorganisms such as bacteria and suspended substances such as metal oxides, the raw water should be supplied before it is supplied to the reverse osmosis membrane module. Pre-treatment is used to remove harmful substances. Specifically, for example, electrolytic chlorine, sodium hypochlorite, or the like is added to raw water to sterilize microorganisms, and the raw water is filtered to remove suspended substances. The chlorine used for sterilization remains in this pretreated water, and this residual chlorine oxidizes and deteriorates the reverse osmosis membrane module.Therefore, before supplying the pretreated water to the reverse osmosis membrane module, a reducing agent is added to the pretreated water. For example, sodium bisulfite is added in an amount of 1 to 10 ppm to remove residual chlorine, thereby preventing oxidative deterioration of the reverse osmosis membrane module. Further, since dissolved oxygen exists in the pretreated water, and dissolved oxygen oxidizes and deteriorates the reverse osmosis membrane module, a material resistant to dissolved oxygen (for example, cross-linked wholly aromatic polyamide) is currently used for the reverse osmosis membrane module. , Prevents oxidative deterioration due to dissolved oxygen.

【0003】[0003]

【発明が解決しようとする課題】しかしながら、従来の
逆浸透膜を用いた脱塩処理方法の場合には、溶存酸素に
強い逆浸透膜モジュールを使用し、重亜硫酸ナトリウム
等の還元剤を添加して前処理水の酸化還元電位を下げて
逆浸透膜モジュールの酸化劣化を防止しているにも拘ら
ず、逆浸透膜が劣化し、逆浸透膜モジュールの脱塩率が
低下するという課題があった。
However, in the case of the conventional desalination treatment method using a reverse osmosis membrane, a reverse osmosis membrane module resistant to dissolved oxygen is used and a reducing agent such as sodium bisulfite is added. Although the redox potential of the pretreated water is lowered to prevent the oxidative deterioration of the reverse osmosis membrane module, there is a problem that the reverse osmosis membrane deteriorates and the desalination rate of the reverse osmosis membrane module decreases. It was

【0004】 本発明は、上記課題を解決するためにな
されたもので、逆浸透膜の酸化劣化を確実に防止し、脱
塩率の低下を抑制することができる逆浸透膜を用いた脱
塩処理方法及びその装置を提供することを目的としてい
る。
The present invention has been made to solve the above problems, and desalination using a reverse osmosis membrane can surely prevent oxidative deterioration of the reverse osmosis membrane and can suppress a decrease in desalination rate. and its object is to provide a processing method and equipment.

【0005】[0005]

【課題を解決するための手段】本発明者らは、逆浸透膜
の酸化劣化のメカニズムについて種々検討した結果、溶
存酸素と銅イオン等の重金属と更に重亜硫酸ナトリウム
が共存すると、何等かの反応を起こし、溶存酸素のみが
存在したり、銅イオン等の重金属と重亜硫酸ナトリウム
が共存する場合よりも格段に強い酸化環境が形成される
ことを知見した。更に、この現象は海水のように高濃度
の塩化ナトリウムを含む被処理水を処理する場合にはこ
の塩化ナトリウムが逆浸透膜に有害な残留塩素濃度を上
昇させる原因になることも知見した。
As a result of various studies on the mechanism of oxidative deterioration of a reverse osmosis membrane, the present inventors have found that when dissolved oxygen, a heavy metal such as copper ion, and sodium bisulfite coexist, some reaction occurs. It was found that an oxidizing environment is formed that is significantly stronger than the case where only dissolved oxygen is present or when heavy metals such as copper ions and sodium bisulfite coexist. Further, it was also found that this phenomenon causes the concentration of residual chlorine, which is harmful to the reverse osmosis membrane, when the treated water such as seawater containing a high concentration of sodium chloride is treated.

【0006】更に、これら三者による酸化環境は重金属
が蓄積される逆浸透膜モジュール内でより強くなること
を見い出した。従って、逆浸透膜モジュールの酸化劣化
を防止する場合には、逆浸透膜モジュールへの供給水の
酸化還元電位を監視するよりも、逆浸透膜モジュール内
の濃縮水の酸化還元電位を監視することの方が遥かに重
要であり、濃縮水の酸化還元電位の監視により逆浸透膜
モジュールの酸化環境をより的確に管理できることを知
見した。
Furthermore, they have found that the oxidizing environment by these three becomes stronger in the reverse osmosis membrane module where heavy metals are accumulated. Therefore, in order to prevent the oxidative deterioration of the reverse osmosis membrane module, the redox potential of the concentrated water in the reverse osmosis membrane module should be monitored rather than the redox potential of the water supplied to the reverse osmosis membrane module. It was found that is much more important, and that the oxidizing environment of the reverse osmosis membrane module can be controlled more accurately by monitoring the redox potential of concentrated water.

【0007】尚、特開平7−308671号公報に本発
明と同種の技術が開示されている。この公報では銅イオ
ンの存在下で塩化ナトリウム、炭酸水素ナトリウム及び
重亜硫酸ナトリウムが共存した時にのみ前述の現象が起
こることが指摘され、その解決策として前処理水をpH
4以下の酸性領域に保って炭酸水素ナトリウムを除去す
る前処理方法、及びその被処理水中の銅イオンをマスキ
ング剤(封鎖剤)により封鎖し、銅イオンの影響を除去
する前処理方法が提案されている。この前処理方法は供
給水の酸化還元電位を低下させる点においては有効であ
るが、この方法はあくまでも供給水の酸化還元電位を管
理する方法で、脱塩処理装置の運転方法という観点から
すれば従来の運転方法の域を出ないものであり、上記課
題を解決するには不十分であった。
A technique similar to the present invention is disclosed in Japanese Patent Laid-Open No. 7-308671. In this publication, it is pointed out that the above-mentioned phenomenon occurs only when sodium chloride, sodium hydrogencarbonate and sodium bisulfite coexist in the presence of copper ions.
A pretreatment method for removing sodium hydrogen carbonate while keeping it in an acidic region of 4 or less, and a pretreatment method for removing the influence of copper ions by blocking copper ions in the water to be treated with a masking agent (blocking agent) have been proposed. ing. This pretreatment method is effective in reducing the oxidation-reduction potential of the feed water, but this method is a method of managing the oxidation-reduction potential of the feed water, and from the viewpoint of operating the desalination treatment device. It is beyond the scope of conventional driving methods, and it was insufficient to solve the above problems.

【0008】 本発明は上記知見に基づいてなされたも
ので、請求項1に記載の逆浸透膜を用いた脱塩処理方法
は、被処理水に重亜硫酸ナトリウム等の還元剤を添加し
て脱塩素処理した後、逆浸透膜を用いて被処理水を脱塩
処理する方法において、上記被処理水を上記逆浸透膜に
供給する前に上記被処理水の溶存酸素を除去し、脱塩処
理後の濃縮水の酸化還元電位を所定の値以下に維持する
ことを特徴とするものである。
The present invention has been made based on the above findings, and the desalination treatment method using a reverse osmosis membrane according to claim 1 is a desalination treatment in which a reducing agent such as sodium bisulfite is added to water to be treated. In the method of desalinating treated water using a reverse osmosis membrane after chlorine treatment, the treated water is converted into the reverse osmosis membrane.
Dissolved oxygen of the water to be treated is removed before the supply, and the oxidation-reduction potential of the concentrated water after the desalting treatment is maintained below a predetermined value.

【0009】[0009]

【0010】 また、本発明の請求項2に記載の逆浸透
膜を用いた脱塩処理方法は、請求項1に記載の発明にお
いて、上記被処理水を真空脱気して溶存酸素を除去する
ことを特徴とすることを特徴とするものである。
A desalination treatment method using a reverse osmosis membrane according to a second aspect of the present invention is the method according to the first aspect , wherein the water to be treated is vacuum degassed to remove dissolved oxygen. It is characterized by that.

【0011】 また、本発明の請求項3に記載の逆浸透
膜を用いた脱塩処理方法は、請求項1または請求項2に
記載の発明において、上記被処理水に重亜硫酸ナトリウ
ムを添加して溶存酸素を除去することを特徴とするも
である。
In addition, the desalination treatment method using a reverse osmosis membrane according to claim 3 of the present invention is the same as that according to claim 1 or 2, wherein sodium bisulfite is added to the water to be treated. also the in which you and removing the dissolved oxygen Te.

【0012】 また、本発明の請求項4に記載の逆浸透
膜を用いた脱塩処理装置は、被処理水に重亜硫酸ナトリ
ウム等の還元剤を添加する薬品添加手段と、この薬品添
加手段により添加された還元剤による脱塩素処理後の被
処理水を脱塩処理する逆浸透膜を用いた逆浸透手段とを
備えた脱塩処理装置において、上記被処理水の溶存酸素
を除去する手段を上記逆浸透手段の上流側に設けると共
に、上記逆浸透手段から流出する濃縮水の酸化還元電位
を監視する手段を上記逆浸透手段の下流側に設け、上記
濃縮水の酸化還元電位を所定の値以下に維持することを
特徴とするものである。
Further, a desalination treatment apparatus using a reverse osmosis membrane according to claim 4 of the present invention comprises a chemical addition means for adding a reducing agent such as sodium bisulfite to water to be treated, and the chemical addition means. In a desalination treatment apparatus equipped with a reverse osmosis means using a reverse osmosis membrane for desalting the water to be treated after dechlorination with an added reducing agent , dissolved oxygen in the water to be treated is
It is common to provide a means for removing water on the upstream side of the reverse osmosis means.
To, a means for monitoring the redox potential of the concentrated water flowing out of the reverse osmosis unit at a downstream side of said reverse osmosis unit, the
It is characterized in maintaining the redox potential of the concentrated water to the predetermined value or less.

【0013】[0013]

【0014】 また、本発明の請求項5に記載の逆浸透
膜を用いた脱塩処理装置は、請求項4に記載の発明にお
いて、上記被処理水の溶存酸素を除去する手段として真
空脱気手段を設けたことを特徴とするものである。
Further, a desalination treatment apparatus using a reverse osmosis membrane according to claim 5 of the present invention is the same as that of the invention according to claim 4 , wherein vacuum degassing is used as means for removing dissolved oxygen in the water to be treated. It is characterized in that means are provided.

【0015】 また、本発明の請求項6に記載の逆浸透
膜を用いた脱塩処理装置は、請求項4に記載の発明にお
いて、上記被処理水の溶存酸素を除去する手段として重
亜硫酸ナトリウムを添加する添加手段を設けたことを特
徴とするものである。
A desalination treatment apparatus using a reverse osmosis membrane according to claim 6 of the present invention is the invention according to claim 4 , wherein sodium bisulfite is used as means for removing dissolved oxygen in the water to be treated. It is characterized in that an adding means for adding is added.

【0016】[0016]

【0017】[0017]

【発明の実施の形態】以下、図1及び図2に示す実施に
基づいて本発明を説明する。尚、各図中、図1は本発明
の逆浸透膜を用いた脱塩処理方法の一実施態様に好適に
用いられる逆浸透方式の脱塩処理装置を示す構成図、図
2は重亜硫酸ナトリウムの添加量と濃縮水の酸化還元電
位と供給水の酸化還元電位の差との関係を示すグラフで
ある。
BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on the embodiments shown in FIGS. In each figure, FIG. 1 is a block diagram showing a reverse osmosis desalination apparatus suitably used in one embodiment of the desalination method using a reverse osmosis membrane of the present invention, and FIG. 2 is sodium bisulfite. 2 is a graph showing the relationship between the amount of addition of water and the difference between the redox potential of concentrated water and the redox potential of feed water.

【0018】まず、本発明の逆浸透膜を用いた脱塩処理
方法の一実施態様に好適に用いられる逆浸透方式の脱塩
処理装置について説明する。本脱塩処理装置は、例えば
逆浸透膜を主体に構成された逆浸透膜モジュールを用い
て被処理水を脱塩処理して淡水化する装置で、一般に、
被処理水の前処理系の下流側に配置されている。被処理
水の前処理系では、通常、被処理水(海水等の原水)に
電解塩素、次亜塩素酸ナトリウムを添加して被処理水中
のバクテリア等の微生物を殺菌し、次いで、被処理水に
塩化第二鉄等の凝集剤を添加して懸濁物質を凝集した
後、濾過装置により凝集物を濾過し、濾過水を前処理水
として濾過水受け槽で一時的に貯留するようにしてあ
る。
First, a reverse osmosis type desalination apparatus suitable for use in one embodiment of the desalination method using the reverse osmosis membrane of the present invention will be described. This desalination treatment device is a device for desalinating and desalinating water to be treated using a reverse osmosis membrane module mainly composed of a reverse osmosis membrane.
It is located on the downstream side of the pretreatment system for the water to be treated. In a pretreatment system for treated water, electrolytic chlorine and sodium hypochlorite are usually added to the treated water (raw water such as seawater) to sterilize microorganisms such as bacteria in the treated water, and then the treated water. After adding a flocculant such as ferric chloride to flocculate the suspended substance, filter the flocculant with a filtration device, and temporarily store the filtered water as pretreated water in the filtered water receiving tank. is there.

【0019】さて、本脱塩処理装置1は、例えば図1に
示すように、濾過水受け槽2内の前処理水を給水ポンプ
3を介して受給し、前処理水を真空脱気して前処理水の
溶存酸素を除去する真空脱気塔4と、真空脱気塔4から
の前処理水に含まれている残留懸濁物質を除去する保安
フィルタ5と、保安フィルタ5で処理された前処理水を
所定の圧力(例えば、66Kg/cm2)まで昇圧し、
高圧供給水として供給する高圧給水ポンプ6と、高圧給
水ポンプ6から受給した高圧供給水を脱塩処理する高圧
逆浸透装置7と、高圧逆浸透装置7の透過水を例えば2
6Kg/cm2に調整し、低圧供給水として供給する低
圧給水ポンプ8と、低圧給水ポンプ8から受給した低圧
供給水を脱塩処理する低圧逆浸透装置9とを備え、高圧
供給水を2段階で脱塩処理して淡水化するように構成さ
れている。そして、上記各構成機器は配管10によって
互いに接続されている。
Now, as shown in FIG. 1, the desalination treatment apparatus 1 receives the pretreatment water in the filtered water receiving tank 2 via the water supply pump 3, and deaerated the pretreatment water in vacuum. A vacuum degassing tower 4 for removing dissolved oxygen in the pretreated water, a safety filter 5 for removing residual suspended substances contained in the pretreated water from the vacuum degassing tower 4, and a safety filter 5 The pretreated water is pressurized to a predetermined pressure (for example, 66 Kg / cm 2 ),
The high-pressure water supply pump 6 supplied as high-pressure supply water, the high-pressure reverse osmosis device 7 for desalting the high-pressure supply water received from the high-pressure water supply pump 6, and the permeated water of the high-pressure reverse osmosis device 7 are, for example, 2
The low-pressure feed pump 8 adjusted to 6 Kg / cm 2 and supplied as low-pressure feed water and the low-pressure reverse osmosis device 9 for desalting the low-pressure feed water received from the low-pressure feed pump 8 are provided, and the high-pressure feed water is provided in two stages. It is designed to be desalinated by desalination. The above-mentioned components are connected to each other by a pipe 10.

【0020】而して、上記真空脱気塔4内には例えばテ
ラレットパッキン等の充填材が充填され、真空ポンプ等
の真空排気装置(図示せず)により溶存酸素濃度を0.
5ppm以下に低下させるために、例えば10〜100
Torrの減圧環境を作るようにしてある。従って、真
空脱気塔4内へ供給された前処理水は充填材と接触しな
がら充填剤表面で薄膜流を作って塔下部へ流下する間に
真空脱気処理により溶存酸素が除去されるようになって
いる。
The vacuum deaeration tower 4 is filled with a filling material such as terralet packing, and the dissolved oxygen concentration is reduced to 0 by a vacuum exhaust device (not shown) such as a vacuum pump.
In order to reduce it to 5 ppm or less, for example, 10 to 100
It is designed to create a reduced pressure environment of Torr. Therefore, the pretreatment water supplied into the vacuum degassing tower 4 forms a thin film flow on the surface of the packing material while contacting with the packing material, and the dissolved oxygen is removed by the vacuum degassing processing while flowing down to the lower part of the tower. It has become.

【0021】上記真空脱気塔4と保安フィルタ5間の配
管10には薬品添加手段として重亜硫酸ナトリウムを供
給する供給源(以下、「SBS供給源」と称す)11が
接続され、このSBS供給源11から脱気処理後の前処
理水に重亜硫酸ナトリウムを添加し、重亜硫酸ナトリウ
ムにより前処理水を脱塩素処理により残留塩素を除去す
るようにしてある。また、上記保安フィルタ5と高圧給
水ポンプ6間の配管10には前処理水の酸化還元電位及
び残留塩素を測定する酸化還元電位計(以下、「ORP
計」と称す)12及び塩素検出点(以下、「Cl2検出
点」と称す)13が設けられ、脱酸素処理、脱塩素処理
後の前処理水の酸化還元電位及び残留塩素を監視するよ
うにしてある。尚、Cl2検出点は被検出水をサンプリ
ングする箇所であり、サンプル水中の残留塩素はO−ト
リジン法により測定するが、残留塩素計により測定する
場合もある。
A supply source (hereinafter referred to as "SBS supply source") 11 for supplying sodium bisulfite as a chemical addition means is connected to the pipe 10 between the vacuum degassing tower 4 and the safety filter 5, and this SBS supply is performed. Sodium bisulfite is added to the pretreated water after degassing from the source 11, and the residual chlorine is removed by dechlorinating the pretreated water with sodium bisulfite. In addition, a pipe 10 between the safety filter 5 and the high-pressure water supply pump 6 is provided with an oxidation-reduction potentiometer (hereinafter referred to as "ORP") for measuring the oxidation-reduction potential and residual chlorine of the pretreated water.
12) and a chlorine detection point (hereinafter referred to as “Cl 2 detection point”) 13 are provided to monitor the redox potential and residual chlorine of pretreated water after deoxygenation and dechlorination. I am doing it. The Cl 2 detection point is a point where the water to be detected is sampled, and the residual chlorine in the sample water is measured by the O-tolidine method, but it may be measured by a residual chlorine meter.

【0022】また、上記高圧逆浸透装置7は、前段の第
1逆浸透膜モジュール71と後段の第2逆浸透膜モジュ
ール72とから構成され、高圧供給水を2段階で順次脱
塩処理するようにしてある。各逆浸透膜モジュール7
1、72は、逆浸透膜を介して一次側と2次側に区画さ
れている。高圧供給水は第1逆浸透膜モジュール71の
一次側へ流入し、脱塩処理後の濃縮水は第1逆浸透膜モ
ジュール71の一次側から流出する。また、第1逆浸透
膜モジュール71の逆浸透膜を透過した透過水はその二
次側から流出するようにしてある。そして、第1逆浸透
膜モジュール71の一次側から流出した濃縮水は第2逆
浸透膜モジュール72の一次側に流入して更に脱塩処理
され、第1、第2逆浸透膜モジュール71、72の二次
側から流出した透過水はそれぞれ処理水として配管10
において合流し、この処理水が低圧給水ポンプ8を介し
て低圧逆浸透装置9へ供給されるようにしてある。ま
た、第2逆浸透膜モジュール72の濃縮水(高圧逆浸透
装置7の濃縮水)は配管10Aを介して動力回収タービ
ン14へ供給され、濃縮水の圧力により動力回収タービ
ン14を駆動させ、高圧給水ポンプ6の駆動力を補充す
るようにしてある。
The high-pressure reverse osmosis device 7 is composed of a first reverse osmosis membrane module 71 at the front stage and a second reverse osmosis membrane module 72 at the rear stage so that the high-pressure feed water is desalted in two stages. I am doing it. Each reverse osmosis membrane module 7
1, 72 are divided into a primary side and a secondary side via a reverse osmosis membrane. The high-pressure supply water flows into the primary side of the first reverse osmosis membrane module 71, and the concentrated water after desalting treatment flows out from the primary side of the first reverse osmosis membrane module 71. The permeated water that has permeated the reverse osmosis membrane of the first reverse osmosis membrane module 71 flows out from the secondary side thereof. Then, the concentrated water that has flowed out from the primary side of the first reverse osmosis membrane module 71 flows into the primary side of the second reverse osmosis membrane module 72 and is further desalted, so that the first and second reverse osmosis membrane modules 71, 72. The permeated water flowing out from the secondary side of the
In this case, the treated water is supplied to the low pressure reverse osmosis device 9 via the low pressure feed pump 8. Further, the concentrated water of the second reverse osmosis membrane module 72 (concentrated water of the high pressure reverse osmosis device 7) is supplied to the power recovery turbine 14 via the pipe 10A, and the power recovery turbine 14 is driven by the pressure of the concentrated water to drive the high pressure. The driving force of the water supply pump 6 is replenished.

【0023】動力回収タービン14には配管10Aを介
して濃縮水槽15、16に接続され、動力回収タービン
14においてエネルギーを消費した濃縮水は常圧で配管
10Aを介して濃縮水槽15、16に供給され、ここで
濃縮水をpH7前後の中性領域に調整し、更に脱塩素処
理後の余剰の重亜硫酸ナトリウムを酸化するなどして濃
縮水を無害化した後放水するようにしてある。また、動
力回収タービン14と濃縮水槽15、16を連絡する配
管10Aには濃縮水の酸化還元電位及び残留塩素を測定
するORP計12A及びCl2検出点13Aが設けら
れ、濃縮水の酸化還元電位及び残留塩素を監視するよう
にしてある。
The power recovery turbine 14 is connected to the concentrated water tanks 15 and 16 via the pipe 10A, and the concentrated water which has consumed energy in the power recovery turbine 14 is supplied to the concentrated water tanks 15 and 16 at atmospheric pressure via the pipe 10A. Here, the concentrated water is adjusted to a neutral region around pH 7, and the concentrated sodium is detoxified by further oxidizing the excess sodium bisulfite after the dechlorination treatment and then discharged. Further, an ORP meter 12A for measuring the oxidation-reduction potential of the concentrated water and residual chlorine and a Cl 2 detection point 13A are provided in the pipe 10A connecting the power recovery turbine 14 and the concentrated water tanks 15, 16 to provide the oxidation-reduction potential of the concentrated water. Also, the residual chlorine is monitored.

【0024】上記第1、第2逆浸透膜モジュール71、
72としては、例えば従来から公知のスパイラル型、管
型、平面型及び中空糸型等を用いることができる。ま
た、第1逆浸透膜モジュールに用いられる逆浸透膜とし
ては、例えば三酢酸セルロース膜、架橋全芳香族ポリア
ミド等の従来公知の溶存酸素に強い半透膜を用いること
ができる。このことは後述する低圧逆浸透装置9の場合
ついても同様のことが云える。
The first and second reverse osmosis membrane modules 71,
As 72, for example, a conventionally known spiral type, tubular type, flat type, hollow fiber type or the like can be used. As the reverse osmosis membrane used in the first reverse osmosis membrane module, a conventionally known semipermeable membrane that is strong against dissolved oxygen, such as a cellulose triacetate membrane or a cross-linked wholly aromatic polyamide, can be used. The same can be said for the low-pressure reverse osmosis device 9 described later.

【0025】また、上記低圧逆浸透装置9は低圧給水ポ
ンプ8からの低圧供給水を例えば3段階の第1、第2、
第3逆浸透膜モジュール91、92、93で順次脱塩処
理し、淡水化するように構成されている。低圧逆浸透装
置9内では、第1、第2逆浸透膜モジュール91、92
において順次脱塩処理され、最終の濃縮水が第3逆浸透
膜モジュール93の一次側から流出するようにしてあ
る。この濃縮水は、高圧逆浸透装置7から流出する濃縮
水よりも格段に塩濃度が低いため、回収配管17を介し
て上記濾過水受け槽2で回収され、前処理系からの前処
理水と共に上述の脱塩処理を行うようにしてある。ま
た、第1、第2、第3逆浸透膜モジュール91、92、
93それぞれの二次側から流出する透過水は塩類が殆ど
除去されて淡水化された状態で配管10において合流
し、配管10を介してサックバックタンク18内に流入
し、ここで透過水の一部が貯留される。サックバックタ
ンク18は逆浸透装置が停止した時に正浸透により浸出
する水量を供給する水を貯留するようにしてある。
The low-pressure reverse osmosis device 9 supplies the low-pressure feed water from the low-pressure feed pump 8 to, for example, three stages of first, second, and third stages.
The third reverse osmosis membrane modules 91, 92, 93 are sequentially desalted to be desalinated. In the low-pressure reverse osmosis device 9, the first and second reverse osmosis membrane modules 91, 92
In the above, the desalination process is sequentially performed, and the final concentrated water is allowed to flow out from the primary side of the third reverse osmosis membrane module 93. Since this concentrated water has a much lower salt concentration than the concentrated water flowing out from the high-pressure reverse osmosis device 7, it is recovered in the filtered water receiving tank 2 through the recovery pipe 17 and together with the pretreated water from the pretreatment system. The desalting treatment described above is performed. In addition, the first, second and third reverse osmosis membrane modules 91, 92,
93 The permeated water flowing out from each secondary side joins in the pipe 10 in a state where most of the salts are removed and is desalinated, and flows into the suck back tank 18 through the pipe 10, where one of the permeated water is Part is stored. The suck back tank 18 stores water that supplies the amount of water that leaches out by normal osmosis when the reverse osmosis device is stopped.

【0026】次に、上記脱塩処理装置1を用いた本発明
の脱塩処理方法の一実施態様について説明する。まず、
濾過水受け槽2内の前処理水(被処理水に相当する)を
給水ポンプ3を介して例えば20〜200m3/時の流
量で真空脱気塔4内へ供給すると、真空脱気塔4内では
充填材を通過する間に前処理水を真空脱気して溶存酸素
を除去する。真空脱気塔4から流出した脱酸素処理後の
前処理水にはSBS供給源11から重亜硫酸ナトリウム
を添加し、その濃度を例えば3〜15ppm、例えば9
ppmに調整し、前処理水が保安フィルタ5を経由して
高圧逆浸透装置7へ到達するまでの間に重亜硫酸ナトリ
ウムにより前処理水の残留塩素を還元、除去する。重亜
硫酸ナトリウムの添加量は前処理水の水質にもよるが、
通常は残留塩素を除去する量、例えば残留塩素が1当量
に対して2当量以上が好ましい。そして、保安フィルタ
5から前処理水が流出すると、ORP計12及びCl2
検出点13によりその前処理水の酸化還元電位及び塩素
を測定する。その測定結果によれば、前処理水(高圧逆
浸透装置7への供給水)の酸化還元電位は−93〜31
mVであり、塩素は検出されなかった。
Next, one embodiment of the desalination treatment method of the present invention using the desalination treatment apparatus 1 will be described. First,
When pretreatment water (corresponding to water to be treated) in the filtered water receiving tank 2 is supplied into the vacuum degassing tower 4 through the water supply pump 3 at a flow rate of 20 to 200 m 3 / hour, for example, the vacuum degassing tower 4 Inside, the pretreated water is vacuum degassed while passing through the filler to remove dissolved oxygen. Sodium bisulfite is added from the SBS supply source 11 to the pretreated water after the deoxygenation treatment that has flowed out from the vacuum degassing tower 4, and the concentration thereof is, for example, 3 to 15 ppm, for example 9
The residual chlorine of the pretreatment water is reduced and removed by sodium bisulfite until the pretreatment water reaches the high pressure reverse osmosis device 7 through the safety filter 5 after adjusting to ppm. The amount of sodium bisulfite added depends on the quality of the pretreated water,
Usually, it is preferable to remove residual chlorine, for example, 2 equivalents or more of residual chlorine per 1 equivalent. When the pretreated water flows out from the safety filter 5, the ORP meter 12 and Cl 2
The detection point 13 measures the redox potential and chlorine of the pretreated water. According to the measurement result, the redox potential of the pretreated water (the water supplied to the high-pressure reverse osmosis device 7) was -93 to 31.
mV, chlorine was not detected.

【0027】また、脱酸素、脱塩素後の前処理水を高圧
給水ポンプにより例えば66Kg/cm2に昇圧した
後、高圧逆浸透装置7の第1逆浸透膜モジュール71の
一次側の流入口へ高圧供給水として供給すると、第1逆
浸透膜モジュール71において脱塩処理を受け、第1逆
浸透膜モジュール71の一次側から濃縮水が流出し、二
次側から透過水が流出する。濃縮水は第2逆浸透膜モジ
ュール72の一次側へ流入し、ここで脱塩処理を受けて
更に濃縮されて一次側の流出口から流出し、配管10A
を介して動力回収タービン14へ供給される。また、第
2逆浸透膜モジュール72の二次側の流出口から透過水
が流出し、第1逆浸透膜モジュール71の透過水と配管
10で合流し、低圧給水ポンプ8により圧力調整された
後、低圧逆浸透装置9の第1逆浸透膜モジュール91の
一次側の流入口に供給される。
Further, the pretreated water after deoxygenation and dechlorination is pressurized to, for example, 66 Kg / cm 2 by a high-pressure water supply pump, and then introduced into the inlet on the primary side of the first reverse osmosis membrane module 71 of the high-pressure reverse osmosis device 7. When supplied as high-pressure supply water, the first reverse osmosis membrane module 71 undergoes desalination, concentrated water flows out from the primary side of the first reverse osmosis membrane module 71, and permeated water flows out from the secondary side. The concentrated water flows into the primary side of the second reverse osmosis membrane module 72, undergoes desalting here, is further concentrated, and flows out from the outlet on the primary side.
Is supplied to the power recovery turbine 14 via. Further, after the permeated water flows out from the outlet on the secondary side of the second reverse osmosis membrane module 72, the permeated water merges with the permeated water of the first reverse osmosis membrane module 71 through the pipe 10, and the pressure is adjusted by the low pressure water supply pump 8. , Is supplied to the inlet on the primary side of the first reverse osmosis membrane module 91 of the low-pressure reverse osmosis device 9.

【0028】濃縮水が高圧逆浸透装置7から動力回収タ
ービン14を経由して濃縮水槽15、16へ到達する前
に、ORP計12A及びCl2検出点13Aで濃縮水の
酸化還元電位及び塩素を測定した。その結果、濃縮水の
酸化還元電位は−16〜56mVで、塩素はいずれの検
出点でも検出されなかった。また、高圧逆浸透装置7か
ら流出した濃縮水の銅イオン濃度を測定した結果、その
濃度は1.7ppbであった。これらのことから、第2
逆浸透膜モジュール72から流出した濃縮水に銅イオン
等の重金属イオンが存在しても、前述した理由から濃縮
水の酸化還元電位は所定の値である上記逆浸透膜の制限
値(上記逆浸透膜が許容できる酸化還元電位の値、例え
ば濃縮海水の酸化還元電位に相当する値である350m
V)よりも格段に低く、しかも残留塩素が検出されない
ため、この濃縮水が逆浸透膜モジュール71、72の逆
浸透膜を酸化劣化する虞はない。
Before the concentrated water reaches the concentrated water tanks 15 and 16 from the high-pressure reverse osmosis device 7 via the power recovery turbine 14, the redox potential and chlorine of the concentrated water are measured at the ORP meter 12A and the Cl 2 detection point 13A. It was measured. As a result, the redox potential of the concentrated water was -16 to 56 mV, and chlorine was not detected at any of the detection points. In addition, as a result of measuring the copper ion concentration of the concentrated water flowing out from the high pressure reverse osmosis device 7, the concentration was 1.7 ppb. From these things, the second
Even if heavy metal ions such as copper ions exist in the concentrated water flowing out from the reverse osmosis membrane module 72, the oxidation-reduction potential of the concentrated water is a predetermined value for the above-mentioned reason. The value of the redox potential that the membrane can tolerate, for example, the value corresponding to the redox potential of concentrated seawater, 350 m
Since it is much lower than V) and residual chlorine is not detected, there is no possibility that this concentrated water will oxidatively deteriorate the reverse osmosis membranes of the reverse osmosis membrane modules 71 and 72.

【0029】本実施態様では第1、第2逆浸透膜モジュ
ール71、72において銅イオン等の重金属イオンが捕
捉され、余剰の重亜硫酸ナトリウムが残留していても、
濃縮水において酸化還元電位が上昇し、塩素が発生する
条件、即ち、重金属イオンと重亜硫酸ナトリウムと溶存
酸素の三者が共存する条件のうち、一要素である溶存酸
素が除去されて濃縮水中に残存しないため、上述のよう
に濃縮水の酸化還元電位(−16〜56mV)が供給水
の酸化還元電位(−93〜31mV)と比較してそれほ
ど上昇せず、また、塩素を発生することもなく、ひいて
は逆浸透膜を酸化劣化する虞もない。ところが、重亜硫
酸ナトリウムを9ppm添加して真空脱気処理を施さな
い従来の脱塩処理方法の場合には、下記表1に示すよう
に供給水の酸化還元電位(240mV)と比較すると濃
縮水の酸化還元電位が780mVと急激に上昇し、しか
も塩素を発生し、濃縮水側で極めて強い酸化環境を形成
していることが判る。このことから、逆浸透膜の酸化劣
化を防止するには、供給水側よりも濃縮水側の酸化還元
電位を監視することが極めて重要であることが判る。
尚、本実施形態で使用した供給水中の銅イオン濃度は
0.2〜1.7ppbであり、濃縮水中の銅イオン濃度は
1.2〜1.7ppbであった。また、第1逆浸透膜モジ
ュール71に付着した銅の量を測定した結果、膜モジュ
ール内に収納された逆浸透エレメント1本当たりの銅付
着量は11.44mgであった。
In the present embodiment, even if heavy metal ions such as copper ions are trapped in the first and second reverse osmosis membrane modules 71 and 72 and excess sodium bisulfite remains,
In the concentrated water, the oxidation-reduction potential increases, chlorine is generated, that is, in the condition where the heavy metal ion, sodium bisulfite, and dissolved oxygen coexist, dissolved oxygen, which is one of the elements, is removed to form concentrated water. Since it does not remain, the oxidation-reduction potential (-16 to 56 mV) of the concentrated water does not rise so much as compared with the oxidation-reduction potential (-93 to 31 mV) of the feed water as described above, and chlorine may be generated. Moreover, there is no fear that the reverse osmosis membrane will be oxidatively deteriorated. However, in the case of the conventional desalination treatment method in which 9 ppm of sodium bisulfite was added and the vacuum deaeration treatment was not performed, as shown in Table 1 below, as compared with the oxidation-reduction potential (240 mV) of the feed water, the concentrated water was concentrated. It can be seen that the redox potential rapidly rises to 780 mV, chlorine is generated, and an extremely strong oxidizing environment is formed on the concentrated water side. From this, it can be understood that it is extremely important to monitor the oxidation-reduction potential on the concentrated water side rather than the supply water side in order to prevent the oxidative deterioration of the reverse osmosis membrane.
The copper ion concentration in the feed water used in this embodiment was 0.2 to 1.7 ppb, and the copper ion concentration in the concentrated water was 1.2 to 1.7 ppb. Further, as a result of measuring the amount of copper attached to the first reverse osmosis membrane module 71, the amount of copper attached per reverse osmosis element housed in the membrane module was 11.44 mg.

【0030】 以上説明したように本実施形態によれ
ば、前処理水を高圧逆浸透装置7に供給する前に前処理
水の溶存酸素を除去し、濃縮水の酸化還元電位を所定の
値(逆浸透膜の膜種にもよるが、例えば架橋全芳香族ポ
リアミド製の逆浸透膜の場合には350mV)以下に維
持するようにしたため、ただ単に高圧逆浸透装置7への
供給水の酸化還元電位を下げるだけでは防止し得なかっ
た逆浸透膜の酸化劣化を確実に防止し、脱塩率の低下を
抑制することができる。
As described above, according to this embodiment, the pretreatment is performed before the pretreatment water is supplied to the high-pressure reverse osmosis device 7.
The dissolved oxygen of water is removed, and the oxidation-reduction potential of concentrated water is maintained below a predetermined value (350 mV for reverse osmosis membranes made of cross-linked wholly aromatic polyamide, though it depends on the membrane type of reverse osmosis membrane). Therefore, it cannot be prevented simply by lowering the oxidation-reduction potential of the water supplied to the high-pressure reverse osmosis device 7.
Further, it is possible to reliably prevent the oxidative deterioration of the reverse osmosis membrane and suppress the decrease in the desalination rate.

【0031】 即ち、本実施形態によれば、濃縮水の酸
化還元電位を所定の値以下に維持するために、前処理水
を供給水として高圧逆浸透装置7へ供給する前に、強い
酸化環境を形成する条件(重亜硫酸ナトリウム+溶存酸
素+銅イオン等の重金属イオン)のうち、一要素である
溶存酸素を真空脱気塔4を用いて前処理水から除去す
るようにしたため、他の要素である銅イオン等の重金属
イオン及び余剰の重亜硫酸ナトリウムが供給水及び濃縮
水に残存していても、濃縮水の酸化還元電位を殆ど上昇
させることなく、しかも塩素の発生を防止して高圧逆浸
透装置7の逆浸透膜の酸化劣化を防止することができ、
ひいては重金属イオンを封鎖する封鎖剤を新たに添加す
る必要がない。また、高圧逆浸透装置7の逆浸透膜で銅
イオン等の重金属イオンが捕捉されていても、上述した
理由から逆浸透膜の濃縮水側の膜面において酸化還元電
位が上昇することもなく更に塩素発生することがな
く、高圧逆浸透装置7の逆浸透膜の酸化劣化を効果的に
防止することができる。
That is , according to this embodiment, in order to maintain the oxidation-reduction potential of the concentrated water at a predetermined value or less, before supplying the pretreated water as the feed water to the high pressure reverse osmosis device 7, a strong oxidizing environment is provided. forming a condition of (sodium bisulfite + dissolved oxygen + copper ions such heavy metal ions), dissolved oxygen, which is an element, for which is adapted to remove from the pretreated water by means of a vacuum degassing tower 4, the other Even if heavy metal ions such as copper ions, which are elements, and excess sodium bisulfite remain in the feed water and the concentrated water, the oxidation-reduction potential of the concentrated water is hardly increased, and chlorine is prevented from being generated, resulting in high pressure. It is possible to prevent oxidative deterioration of the reverse osmosis membrane of the reverse osmosis device 7,
Consequently, it is not necessary to newly add a sequestering agent for sequestering heavy metal ions. Further, even if heavy metal ions such as copper ions are trapped in the reverse osmosis membrane of the high-pressure reverse osmosis device 7, the redox potential does not increase on the concentrated water side membrane surface of the reverse osmosis membrane because of the reason described above. may further chlorine also not occur, effectively prevent oxidation deterioration of the reverse osmosis membrane of the high-pressure reverse osmosis device 7.

【0032】次に、本発明の脱塩処理方法の他の実施態
様について説明する。本実施態様では前処理水を真空脱
気して溶存酸素を除去する方法に代えて、濃縮水の酸化
還元電位を所定の値以下に維持するために、前処理水に
重亜硫酸ナトリウムを添加し、重亜硫酸ナトリウムを用
いて残留塩素のみならず溶存酸素をも除去する方法で、
本実施態様に適用される脱塩処理装置は、図1に示す脱
塩処理装置1の真空脱気塔4を省略し、その他は図1に
示したものに準じて構成されたものである。また、被処
理水は上記実施形態で使用したものと同一の水を使用し
た。そこで、図1を参照しながら本実施態様の特徴とな
る部分を中心に説明する。
Next, another embodiment of the desalination treatment method of the present invention will be described. In the present embodiment, instead of the method of vacuum degassing the pretreated water to remove dissolved oxygen, sodium bisulfite is added to the pretreated water in order to maintain the redox potential of the concentrated water at a predetermined value or less. , A method of removing not only residual chlorine but also dissolved oxygen using sodium bisulfite,
The desalination treatment apparatus applied to this embodiment is configured by omitting the vacuum degassing tower 4 of the desalination treatment apparatus 1 shown in FIG. 1 and otherwise configuring it in accordance with that shown in FIG. The water to be treated was the same as that used in the above embodiment. Therefore, with reference to FIG. 1, description will be made focusing on the characteristic part of the present embodiment.

【0033】本実施態様では、濾過水受け槽2内の前処
理水を保安フィルタ4へ供給する前に、配管10を通る
前処理水に重亜硫酸ナトリウムを添加する。従来の脱塩
処理方法の場合には、重亜硫酸ナトリウムは単に被処理
水中に残留する塩素を除去するためにのみ用いられてい
たが、本実施形態の場合には、重亜硫酸ナトリウムの還
元作用に着目し、重亜硫酸ナトリウムを用いて残留塩素
のみならず溶存酸素をも除去する点に大きな特徴があ
る。即ち、重亜硫酸ナトリウムは、水中では塩素と迅速
に反応して塩素を除去するが、酸素との反応は塩素と比
較すれば遅く、溶存酸素を除去する場合には塩素の場合
と比較して多少時間が掛かるが、重亜硫酸ナトリウムは
これら両者と水中で確実に反応し、残留塩素のみならず
溶存酸素をも確実に除去することができる。
In this embodiment, sodium bisulfite is added to the pretreated water passing through the pipe 10 before the pretreated water in the filtered water receiving tank 2 is supplied to the safety filter 4. In the case of the conventional desalination treatment method, sodium bisulfite was used only to remove chlorine remaining in the water to be treated, but in the case of the present embodiment, the reducing action of sodium bisulfite Focusing attention, the major feature is that not only residual chlorine but also dissolved oxygen is removed using sodium bisulfite. That is, sodium bisulfite rapidly reacts with chlorine to remove chlorine in water, but the reaction with oxygen is slower than that of chlorine, and when removing dissolved oxygen, it is slightly more than that of chlorine. Although it takes a long time, sodium bisulfite reacts with both of these in water reliably, and not only residual chlorine but also dissolved oxygen can be surely removed.

【0034】そこで、本実施態様では、重亜硫酸ナトリ
ウムの添加量を下記の表1に示すように変化させ、その
都度、ORP計12、12A及びCl2検出点13、1
3Aを用いて供給水及び濃縮水の酸化還元電位及び残留
塩素をそれぞれ測定し、この測定結果における重亜硫酸
ナトリウムの添加量と酸化還元電位及び塩素との関係を
下記表1に示した。また、重亜硫酸ナトリウムの添加量
と濃縮水の酸化還元電位と供給水の酸化還元電位の差と
の関係を図2に示した。
Therefore, in this embodiment, the addition amount of sodium bisulfite is changed as shown in Table 1 below, and the ORP meter 12, 12A and Cl 2 detection points 13, 1 are changed each time.
3A was used to measure the oxidation-reduction potential and residual chlorine of the feed water and the concentrated water, and the relationship between the addition amount of sodium bisulfite and the oxidation-reduction potential and chlorine in the measurement results is shown in Table 1 below. Further, the relationship between the addition amount of sodium bisulfite and the difference between the redox potential of concentrated water and the redox potential of feed water is shown in FIG.

【0035】下記表1によれば、重亜硫酸ナトリウムの
添加量が40〜100ppmの場合には、濃縮水の酸化
還元電位が295〜130mVで所定の値(前述した逆
浸透膜の制限値である350mV)よりもかなり低く、
塩素も検出されず、しかも濃縮水の酸化還元電位と供給
水のそれ(150〜80mV)と比較してもそれほど上
昇していないことが判る(図2参照)。従って、重亜硫
酸ナトリウムを40〜100ppm添加すると、重亜硫
酸ナトリウムは単に脱塩素処理で消費されるのではな
く、供給水中の脱酸素処理にも消費され、供給水から溶
存酸素を除去するため、脱塩処理前後の供給水、濃縮水
のいずれにおいても、酸化還元電位が低下し、塩素が発
生せず、ひいては逆浸透膜の酸化劣化を防止できること
が判った。従って、濃縮水の酸化還元電位を所定の値以
下の値に維持する上で、重亜硫酸ナトリウムの添加量
は、例えば40〜100ppmが好ましく、60〜10
0ppmがより好ましい。40ppm未満では溶存酸素
を十分に除去できず、特に濃縮水の酸化還元電位が所定
の値を大幅に超えて好ましくなく、逆に100ppmを
超えると供給水及び濃縮水の酸化還元電位の低下率が略
一定になり、それ以上の添加効果が期待できなくなるか
らである。
According to Table 1 below, when the added amount of sodium bisulfite is 40 to 100 ppm, the oxidation-reduction potential of the concentrated water is 295 to 130 mV, which is a predetermined value (the above-mentioned limit value of the reverse osmosis membrane). Considerably lower than 350 mV),
Chlorine was not detected, and it was found that the oxidation-reduction potential of the concentrated water and that of the feed water (150 to 80 mV) did not increase so much (see FIG. 2). Therefore, when sodium bisulfite is added in an amount of 40 to 100 ppm, sodium bisulfite is not simply consumed by the dechlorination treatment but also consumed by the deoxygenation treatment of the feed water, and the dissolved oxygen is removed from the feed water. It was found that the oxidation-reduction potential was lowered and chlorine was not generated in both the feed water and the concentrated water before and after the salt treatment, and consequently the oxidative deterioration of the reverse osmosis membrane could be prevented. Therefore, in order to maintain the oxidation-reduction potential of concentrated water at a predetermined value or less, the addition amount of sodium bisulfite is preferably 40 to 100 ppm, and 60 to 10 ppm, for example.
0 ppm is more preferable. If it is less than 40 ppm, dissolved oxygen cannot be sufficiently removed, and in particular, the oxidation-reduction potential of the concentrated water greatly exceeds a predetermined value, which is not preferable. On the contrary, if it exceeds 100 ppm, the reduction rate of the oxidation-reduction potential of the feed water and the concentrated water decreases. This is because it becomes almost constant, and further addition effects cannot be expected.

【0036】また、重亜硫酸ナトリウムの添加量の効果
は、図2を参照すればより明確になる。即ち、重亜硫酸
ナトリウムを40ppm添加する時点から供給水の酸化
還元電位に対する濃縮水の酸化還元電位の上昇率が格段
に低くなり、濃縮水の酸化還元電位を極めて低い水準に
維持することができ、逆浸透膜での酸化劣化を効率良く
防止できる。
Further, the effect of the added amount of sodium bisulfite becomes clearer with reference to FIG. That is, from the time when 40 ppm of sodium bisulfite was added, the rate of increase in the redox potential of concentrated water with respect to the redox potential of the feed water was significantly reduced, and the redox potential of concentrated water could be maintained at an extremely low level. Oxidative deterioration in the reverse osmosis membrane can be efficiently prevented.

【0037】ところが、従来の添加量(3〜11pp
m)の場合には、下記表1からも明らかなように、供給
水の酸化還元電位が240〜150mVを示し、濃縮水
の酸化還元電位が765〜809mVと極めて高く、供
給水と比較しても格段に上昇し、極めて強い酸化環境を
形成することが判った。従って、3〜11ppmの添加
量では溶存酸素を除去できないため、逆浸透膜の近傍で
強い酸化環境を形成する3条件(重亜硫酸ナトリウム+
溶存酸素+銅イオン等の重金属イオン)が揃い、より強
い酸化環境が形成され、下記表1に示すように濃縮水の
酸化還元電位が急激に上昇し逆浸透膜の制限値である3
50mVを遥かに超え、しかも塩素を発生することが判
った。このことから上記実施態様と同様に逆浸透膜の酸
化劣化を防止するには、供給水側の酸化還元電位を管理
するよりも濃縮水側の酸化還元電位を管理することの方
が極めて重要であることが判る。尚、重亜硫酸ナトリウ
ムの添加量が極めて少ない1ppmの場合には、下記表
1から明らかなように供給水側及び濃縮水側とも酸化還
元電位が比較的低く、塩素の発生が認められないが、こ
のような低い添加量では重亜硫酸ナトリウムを添加する
当初の目的である残留塩素(滅菌用として添加した塩素
の余剰分)を余裕をもって安全に除去できないため、重
亜硫酸ナトリウムの添加量としては実用的でない。
However, the conventional addition amount (3 to 11 pp
In the case of m), as is clear from Table 1 below, the oxidation-reduction potential of the feed water is 240 to 150 mV, and the oxidation-reduction potential of the concentrated water is 765 to 809 mV, which is extremely high. Was also found to rise markedly, forming an extremely strong oxidizing environment. Therefore, since dissolved oxygen cannot be removed with an addition amount of 3 to 11 ppm, there are three conditions (sodium bisulfite +
Dissolved oxygen + heavy metal ions such as copper ions) are aligned, a stronger oxidizing environment is formed, and as shown in Table 1 below, the redox potential of the concentrated water rises sharply, which is the limiting value of the reverse osmosis membrane.
It was found that it far exceeded 50 mV and generated chlorine. From this, in order to prevent the oxidative deterioration of the reverse osmosis membrane as in the above embodiment, it is extremely important to manage the redox potential on the concentrated water side rather than the redox potential on the feed water side. I know there is. In addition, when the addition amount of sodium bisulfite is extremely small at 1 ppm, as is clear from Table 1 below, the redox potentials are relatively low on both the feed water side and the concentrated water side, and chlorine generation is not observed, With such a low amount of addition, residual chlorine (excess chlorine added for sterilization), which was the original purpose of adding sodium bisulfite, cannot be safely removed with sufficient margin, so it is practical as an addition amount of sodium bisulfite. Not.

【0038】[0038]

【表1】 [Table 1]

【0039】従って、本実施形態によれば、溶存酸素を
脱気除去する方法に代えて、溶存酸素をも除去できる量
の重亜硫酸ナトリウムを40〜100ppm添加するこ
とにより、真空脱気により溶存酸素を除去する場合と同
様の作用効果を期することができる。
Therefore, according to this embodiment, 40 to 100 ppm of sodium bisulfite in an amount that can also remove dissolved oxygen is added instead of the method of removing dissolved oxygen by degassing, and the dissolved oxygen is removed by vacuum degassing. It is possible to expect the same action and effect as the case of removing.

【0040】また、本発明の脱塩処理方法は濃縮水の酸
化還元電位を所定の値以下に維持する点に特徴を有し、
その具体的な方法として、濃縮水で強い酸化環境を形成
する条件(重亜硫酸ナトリウム+溶存酸素+銅イオン等
の重金属イオン)のうち、一要素である溶存酸素を前処
理水から除去する方法について説明したが、前処理水中
の銅イオン等の重金属イオンの酸化触媒作用を失効させ
る方法であっても同様の作用効果を期することができ
る。この方法として、例えば薬品添加手段として銅イオ
ン等の重金属イオンとキレート化合物を作るマスキング
剤を添加する装置を設け、前処理水にマスキング剤を添
加し、重金属イオンのキレート化合物を作る方法があ
る。
Further, the desalination treatment method of the present invention is characterized in that the oxidation-reduction potential of concentrated water is maintained below a predetermined value.
As a concrete method, about the method of removing the dissolved oxygen, which is one of the factors, from the pretreated water under the conditions (sodium bisulfite + dissolved oxygen + heavy metal ions such as copper ions) that form a strong oxidizing environment with concentrated water As described above, the same action and effect can be expected even by the method of deactivating the oxidation catalyst action of heavy metal ions such as copper ions in the pretreated water. As this method, for example, there is a method in which a device for adding a heavy metal ion such as copper ion and a masking agent for forming a chelate compound is provided as a chemical addition means, and the masking agent is added to pretreatment water to form a chelate compound for a heavy metal ion.

【0041】次に、本発明の脱塩処理装置の運転方法の
一実施態様について説明する。上記各実施態様は被処理
水の脱塩処理するに当たり、被処理水中で酸化環境を作
る条件のうち、前処理水から溶存酸素を除去し、溶存酸
素の除去により脱塩処理後の濃縮水の酸化還元電位を所
定の値以下に維持する脱塩処理方法について具体的に説
明したが、本発明の脱塩処理装置の運転方法は、逆浸透
膜において酸化環境を作る条件のうち、逆浸透膜での重
金属類の蓄積量を濃縮水の酸化還元電位を介して管理
し、濃縮水の酸化還元電位がその管理値に達した時点で
逆浸透膜を酸洗浄により除去するようにした運転方法
で、この運転方法は、従来の脱塩処理方法に対しても本
発明の脱塩処理方法に対しても適用することができる
が、従来の脱塩処理方法に適用した場合にも顕著な効果
を発揮する。濃縮水の酸化還元電位を監視手段としては
ORP計12Aが用いられる。
Next, one embodiment of the method for operating the desalination treatment apparatus of the present invention will be described. In each of the above-described embodiments, in the desalination treatment of the water to be treated, among the conditions for creating an oxidizing environment in the water to be treated, dissolved oxygen is removed from the pretreated water, and the concentrated water after desalination treatment is removed by removing the dissolved oxygen. Although the desalination treatment method for maintaining the redox potential below a predetermined value has been specifically described, the operating method of the desalination treatment apparatus of the present invention is that the reverse osmosis membrane is one of the conditions for creating an oxidizing environment in the reverse osmosis membrane. The operating method is to control the accumulated amount of heavy metals through the oxidation-reduction potential of concentrated water, and to remove the reverse osmosis membrane by acid washing when the oxidation-reduction potential of concentrated water reaches the control value. Although this operating method can be applied to both the conventional desalination treatment method and the desalination treatment method of the present invention, it has a remarkable effect when applied to the conventional desalination treatment method. Demonstrate. An ORP meter 12A is used as a means for monitoring the redox potential of the concentrated water.

【0042】即ち、本実施態様の運転方法の場合には、
脱塩処理後の濃縮水の酸化還元電位をORP計12Aで
監視し、その酸化還元電位を所定の値(逆浸透膜の制限
値、例えば350mV)以下に維持するために、この所
定の値以下の値(例えば、300mV)を濃縮水の酸化
還元電位の管理値として設定し、ORP計12Aで測定
した酸化還元電位の値が管理値に達した時に、脱塩処理
装置1を一旦停止し、高圧逆浸透装置7の第1、第2逆
浸透膜モジュール71、72をクエン酸等を用いて酸洗
浄し、各モジュール71、72の逆浸透膜に蓄積された
重金属類を除去した後、運転を再開する。管理値の監視
方法としては、例えば、脱塩処理装置の制御装置(図示
せず)に管理値をソフト的に設定し、ORP計12Aの
測定値が管理値に達した時に制御装置を介して自動的に
警報を発し、その旨オペレータに報知する方法、あるい
はオペレータがORP計12Aによる測定値を直接目視
により監視する方法等がある。従って、脱塩処理方法自
体は溶存酸素、重亜硫酸ナトリウム及び銅イオン等の重
金属イオンが共存する従来の脱塩処理方法で脱塩処理を
行っても、逆浸透膜で強い酸化環境が形成される前に、
ORP計12Aの測定値が管理値に達した時点で銅イオ
ン等の重金属類の蓄積量が逆浸透膜の許容値に達したこ
とを知ることができ、この時点で重金属類を除去するこ
とにより濃縮水の酸化還元電位の値を常に所定の値以下
に維持することができる。尚、この運転方法において、
上記管理値を所定の値からかけ離れた低い値に設定する
と、酸洗浄の回数が多くなって脱塩処理装置1を運転す
る上で好ましくなく、現実的でない。
That is, in the case of the operating method of this embodiment,
The redox potential of the concentrated water after desalting treatment is monitored by the ORP meter 12A, and in order to maintain the redox potential at a predetermined value (reverse osmosis membrane limit value, for example, 350 mV) or less, this predetermined value or less Value (for example, 300 mV) is set as the control value of the redox potential of the concentrated water, and when the value of the redox potential measured by the ORP meter 12A reaches the control value, the desalination treatment apparatus 1 is temporarily stopped, The first and second reverse osmosis membrane modules 71 and 72 of the high-pressure reverse osmosis device 7 are washed with acid using citric acid or the like to remove heavy metals accumulated in the reverse osmosis membranes of the modules 71 and 72, and then the operation is performed. To resume. As a method of monitoring the control value, for example, a control value (not shown) of the desalination treatment apparatus is set as software, and when the measured value of the ORP meter 12A reaches the control value, the control value is set via the control apparatus. There is a method of automatically issuing an alarm and notifying the operator of that fact, a method of directly monitoring the measurement value by the operator by the ORP meter 12A, or the like. Therefore, the desalting treatment method itself forms a strong oxidizing environment in the reverse osmosis membrane even if the desalting treatment is carried out by the conventional desalting treatment method in which heavy metal ions such as dissolved oxygen, sodium bisulfite and copper ions coexist. before,
When the measured value of the ORP meter 12A reaches the control value, it can be known that the accumulated amount of heavy metals such as copper ions has reached the allowable value of the reverse osmosis membrane, and by removing the heavy metals at this point. The value of the oxidation-reduction potential of concentrated water can be always maintained below a predetermined value. In this operating method,
If the control value is set to a low value that is far from the predetermined value, the number of times of acid cleaning is increased, which is not preferable for operating the desalination treatment apparatus 1 and is not realistic.

【0043】さて、実際に高圧逆浸透装置7の各逆浸透
膜モジュールをクエン酸洗浄した後、脱塩処理装置1を
運転し、運転の間に、高圧逆浸透装置7の供給水及び濃
縮水それぞれの酸化還元電位及び塩素をORP計12、
12A及びCl2検出点13、13Aで測定し、測定結
果を逐次監視した。そして、ORP計12、12Aの複
数の計測値の平均値を求めた結果、供給水の酸化還元電
位の平均値が130mV、濃縮水のそれが150mV
で、所定の値である350mVより格段に低い値を示
し、濃縮水の酸化還元電位の実質的な上昇は認められ
ず、また、残留塩素も検出されなかった。ところが、酸
洗浄を行わず、銅イオンが付着したまま同様の脱塩処理
を継続して行うと、ORP計12Aで測定される濃縮水
の酸化還元電位の値は表1(重亜硫酸ナトリウムの添加
量が9ppmの場合)に示すように供給水で240m
V、濃縮水で780mVで、所定の値より遥かに高く、
濃縮水の酸化還元電位が急激に上昇して逆浸透膜モジュ
ール71、72において強い酸化環境を形成し、逆浸透
膜モジュール71、72を酸化劣化する虞があることが
判った。この結果から、濃縮水の酸化還元電位をORP
計12Aで監視しながら脱塩処理装置1を運転し、管理
値に達した時点で第1、第2逆浸透膜モジュール71、
72を酸洗浄することで、濃縮水の酸化還元電位を常に
所定の値以下に維持することができ、両モジュール7
1、72の酸化劣化を防止する上で有効であることが判
る。尚、ORP計12Aの測定値が300mVに達した
時点で、高圧逆浸透装置7の第1、第2逆浸透膜モジュ
ール71をクエン酸洗浄した結果、例えば逆浸透モジュ
ール1本当たり11.44mgの銅が除去された。尚、
脱塩処理時の供給水の銅イオン濃度は0.2ppbであ
り、濃縮水の銅イオン濃度は1.7ppbであった。
Now, after actually cleaning each reverse osmosis membrane module of the high pressure reverse osmosis device 7 with citric acid, the desalination treatment device 1 is operated, and during the operation, the feed water and concentrated water of the high pressure reverse osmosis device 7 are operated. ORP meter 12 for each redox potential and chlorine,
12A and Cl 2 detection points 13 and 13A were measured, and the measurement results were sequentially monitored. Then, as a result of obtaining the average value of a plurality of measured values of the ORP meters 12 and 12A, the average value of the oxidation-reduction potential of the supply water is 130 mV and that of the concentrated water is 150 mV.
The value was markedly lower than the predetermined value of 350 mV, no substantial increase in the oxidation-reduction potential of the concentrated water was observed, and no residual chlorine was detected. However, if the same desalting treatment is continuously carried out with the copper ions attached without performing the acid cleaning, the redox potential value of the concentrated water measured by the ORP meter 12A is shown in Table 1 (addition of sodium bisulfite). When the amount is 9ppm)
V, 780 mV with concentrated water, much higher than the prescribed value,
It was found that there is a possibility that the redox potential of the concentrated water rapidly increases to form a strong oxidizing environment in the reverse osmosis membrane modules 71, 72, and the reverse osmosis membrane modules 71, 72 are oxidatively deteriorated. From this result, the oxidation-reduction potential of the concentrated water is determined by the ORP.
The desalination treatment apparatus 1 is operated while monitoring with a total of 12 A, and when the control value is reached, the first and second reverse osmosis membrane modules 71,
By acid-cleaning 72, the oxidation-reduction potential of the concentrated water can be always maintained below a predetermined value.
It can be seen that it is effective in preventing oxidative deterioration of Nos. 1 and 72. At the time when the measured value of the ORP meter 12A reaches 300 mV, the first and second reverse osmosis membrane modules 71 of the high pressure reverse osmosis device 7 are washed with citric acid. Copper was removed. still,
The copper ion concentration of the feed water during the desalting treatment was 0.2 ppb, and the copper ion concentration of the concentrated water was 1.7 ppb.

【0044】従って、本実施態様によれば、脱塩処理方
法自体が従来方法と同一であっても、ORP計12Aで
濃縮水の酸化還元電位の管理値を介して銅イオン等の重
金属類の逆浸透膜での蓄積量を監視し、その蓄積量が逆
浸透膜の許容値に達した時点を予め設定された管理値に
より知ることができ、その時点で逆浸透膜を酸洗浄して
重金属類を除去することで常に濃縮水の酸化還元電位の
値を所定の値以下に維持することができるため、前処理
水中に溶存酸素、重亜硫酸ナトリウム及び銅イオン等の
重金属イオンが共存する条件下で脱塩処理を行っても高
圧逆浸透装置7等の逆浸透膜の酸化劣化を確実に防止す
ることができる。
Therefore, according to the present embodiment, even if the desalting method itself is the same as the conventional method, heavy metals such as copper ions can be removed through the ORP meter 12A through the control value of the oxidation-reduction potential of the concentrated water. The accumulated amount in the reverse osmosis membrane can be monitored and the time when the accumulated amount reaches the allowable value of the reverse osmosis membrane can be known by the preset control value. Since it is possible to always maintain the redox potential value of the concentrated water below a predetermined value by removing the impurities, dissolved oxygen, sodium bisulfite and copper ions and other heavy metal ions coexist in the pretreated water. Even if the desalination process is performed in step 1, the oxidative deterioration of the reverse osmosis membrane of the high pressure reverse osmosis device 7 or the like can be reliably prevented.

【0045】上述した本発明の運転方法の実施態様では
従来の脱塩処理方法で脱塩処理する装置を運転する場合
に本発明の運転方法を適用した例について説明したが、
本発明は、酸化還元電位を常に所定の値以下に維持する
前述した本発明の脱塩処理方法で脱塩処理する装置の運
転に適用しても良い。
In the above-described embodiment of the operating method of the present invention, an example in which the operating method of the present invention is applied to the case of operating the apparatus for desalting treatment by the conventional desalting treatment method has been described.
The present invention may be applied to the operation of an apparatus for desalting treatment by the desalting treatment method of the present invention, which always maintains the redox potential below a predetermined value.

【0046】尚、本発明の脱塩処理方法及びその装置は
上記実施形態に何等制限されるものではなく、真空脱気
塔4による減圧の程度や重亜硫酸ナトリウムの添加量は
必要に応じて適宜設定することができる。要は、本発明
の脱塩処理方法及びその装置は脱塩処理後の濃縮水の酸
化還元電位を所定の値以下に維持する脱塩処理方法及び
装置や、濃縮水の酸化還元電位を所定の値以下に維持す
るために、被処理水の溶存酸素を真空脱気や重亜硫酸ナ
トリウムにより除去する脱塩処理方法及び装置であれば
良く、そのような発明であれば本発明に包含される。ま
た、本発明の脱塩処理装置の運転方法は、濃縮水の酸化
還元電位が管理値に達した時に逆浸透膜を酸洗浄して逆
浸透膜に蓄積された重金属類を除去する運転方法であれ
ば良く、そのような発明であれば本発明に包含される。
The desalination treatment method and the apparatus therefor of the present invention are not limited to the above embodiment, and the degree of depressurization by the vacuum degassing tower 4 and the amount of sodium bisulfite added are appropriately determined. Can be set. In short, the desalination treatment method and apparatus of the present invention are the desalination treatment method and apparatus for maintaining the redox potential of concentrated water after desalting treatment at a predetermined value or less, and the redox potential of concentrated water to a predetermined value. In order to maintain the value below the value, a desalination treatment method and apparatus for removing dissolved oxygen in the water to be treated by vacuum degassing or sodium bisulfite, and such an invention is included in the present invention. Further, the operating method of the desalination apparatus of the present invention is an operating method of removing the heavy metals accumulated in the reverse osmosis membrane by acid-washing the reverse osmosis membrane when the oxidation-reduction potential of concentrated water reaches a control value. It suffices if there is any, and such an invention is included in the present invention.

【0047】また、本発明は、被処理水が銅イオン等の
重金属を含有したり、逆浸透膜装置の入口から重金属が
混入したり、逆浸透膜装置の洗浄水や水張り水等から逆
浸透膜装置内に重金属が混入したりすることにより逆浸
透膜モジュールの濃縮水側に重金属が蓄積する場合に有
効である。
Further, in the present invention, the water to be treated contains heavy metals such as copper ions, heavy metals are mixed in from the inlet of the reverse osmosis membrane device, and reverse osmosis is made from washing water or flooded water of the reverse osmosis membrane device. This is effective when heavy metals accumulate in the concentrated water side of the reverse osmosis membrane module due to the inclusion of heavy metals in the membrane device.

【0048】[0048]

【発明の効果】本発明の請求項1〜請求項6に記載の発
明によれば、被処理水を上記逆浸透膜に供給する前に上
記被処理水の溶存酸素を除去し、逆浸透膜による濃縮水
の酸化還元電位を所定の値以下に維持するようにしたた
め、銅イオン等の重金属イオンの存在下でも、逆浸透膜
の酸化劣化を確実に防止し、脱塩率の低下を抑制するこ
とができる逆浸透膜を用いた脱塩処理方法及びその装置
を提供することができる。
According to the inventions described in claims 1 to 6 , before the water to be treated is supplied to the reverse osmosis membrane,
Since the dissolved oxygen of the water to be treated is removed and the oxidation-reduction potential of the concentrated water by the reverse osmosis membrane is maintained below a predetermined value , the reverse osmosis membrane is oxidatively deteriorated even in the presence of heavy metal ions such as copper ions. It is possible to provide a desalination treatment method using a reverse osmosis membrane and an apparatus therefor capable of reliably preventing the above-mentioned phenomenon and suppressing a decrease in the desalination rate.

【0049】[0049]

【図面の簡単な説明】[Brief description of drawings]

【図1】本発明の逆浸透膜を用いた脱塩処理方法の一実
施態様に好適に用いられる逆浸透方式の脱塩処理装置を
示す構成図である。
FIG. 1 is a configuration diagram showing a reverse osmosis type desalination apparatus suitably used in an embodiment of a desalination method using a reverse osmosis membrane of the present invention.

【図2】重亜硫酸ナトリウムの添加量と濃縮水の酸化還
元電位と供給水の酸化還元電位の差との関係を示すグラ
フである。
FIG. 2 is a graph showing the relationship between the amount of sodium bisulfite added, the redox potential of concentrated water, and the difference in redox potential of feed water.

【符号の説明】[Explanation of symbols]

4 真空脱気塔(溶存酸素を除去する手段) 7 高圧逆浸透装置 9 低圧逆浸透装置 11 重亜硫酸ナトリウムの供給源(溶存酸素を除去
する手段) 12A ORP計(濃縮水の酸化還元電位を監視する手
段) 71 高圧逆浸透装置の第1逆浸透モジュール 72 高圧逆浸透装置の第2逆浸透モジュール 91 低圧逆浸透装置の第1逆浸透モジュール 92 低圧逆浸透装置の第2逆浸透モジュール 93 低圧逆浸透装置の第3逆浸透モジュール
4 Vacuum degassing tower (means for removing dissolved oxygen) 7 High-pressure reverse osmosis device 9 Low-pressure reverse osmosis device 11 Source of sodium bisulfite (means for removing dissolved oxygen) 12A ORP meter (monitors redox potential of concentrated water) 71) First reverse osmosis module 72 of high-pressure reverse osmosis apparatus 72 Second reverse osmosis module 91 of high-pressure reverse osmosis apparatus First reverse osmosis module 92 of low-pressure reverse osmosis apparatus 93 Second reverse osmosis module 93 of low-pressure reverse osmosis apparatus Third reverse osmosis module of osmosis device

───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 FI B01D 61/08 B01D 61/08 61/12 61/12 (72)発明者 村上 良明 東京都文京区本郷5丁目5番16号 オル ガノ株式会社内 (72)発明者 下坂 和孝 東京都文京区本郷5丁目5番16号 オル ガノ株式会社内 (56)参考文献 特開 平9−57076(JP,A) (58)調査した分野(Int.Cl.7,DB名) B01D 61/00 - 71/82 C02F 1/44 ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 7 Identification code FI B01D 61/08 B01D 61/08 61/12 61/12 (72) Inventor Yoshiaki Murakami 5-5-16 Hongo, Bunkyo-ku, Tokyo Organo Corporation (72) Inventor Kazutaka Shimosaka 5-5-16 Hongo, Bunkyo-ku, Tokyo Organo Corporation (56) Reference JP-A-9-57076 (JP, A) (58) Fields investigated (Int.Cl. 7 , DB name) B01D 61/00-71/82 C02F 1/44

Claims (6)

(57)【特許請求の範囲】(57) [Claims] 【請求項1】 被処理水に重亜硫酸ナトリウム等の還元
剤を添加して脱塩素処理した後、逆浸透膜を用いて被処
理水を脱塩処理する方法において、上記被処理水を上記
逆浸透膜に供給する前に上記被処理水の溶存酸素を除去
し、脱塩処理後の濃縮水の酸化還元電位を所定の値以下
に維持することを特徴とする逆浸透膜を用いた脱塩処理
方法。
1. A After dechlorination by adding a reducing agent sodium bisulfite or the like to the water to be treated, a method for desalting treatment water using a reverse osmosis membrane, the said treatment water
Removes dissolved oxygen in the water to be treated before supplying it to the reverse osmosis membrane
Then, the desalination treatment method using a reverse osmosis membrane is characterized in that the redox potential of the concentrated water after the desalination treatment is maintained at a predetermined value or less.
【請求項2】 上記被処理水を真空脱気して溶存酸素を
除去することを特徴とする請求項1に記載の逆浸透膜を
用いた脱塩処理方法。
2. The desalination treatment method using a reverse osmosis membrane according to claim 1 , wherein the water to be treated is vacuum degassed to remove dissolved oxygen.
【請求項3】 上記被処理水に重亜硫酸ナトリウムを添
加して溶存酸素を除去することを特徴とする請求項1ま
たは請求項2に記載の逆浸透膜を用いた脱塩処理方法。
3. A process according to claim 1, characterized in that the removal of dissolved oxygen by the addition of sodium bisulfite to the water to be treated or
Other desalting treatment method using a reverse osmosis membrane of claim 2.
【請求項4】 被処理水に重亜硫酸ナトリウム等の還元
剤を添加する薬品添加手段と、この薬品添加手段により
添加された還元剤による脱塩素処理後の被処理水を脱塩
処理する逆浸透膜を用いた逆浸透手段とを備えた脱塩処
理装置において、上記被処理水の溶存酸素を除去する手
段を上記逆浸透手段の上流側に設けると共に、上記逆浸
透手段から流出する濃縮水の酸化還元電位を監視する手
段を上記逆浸透手段の下流側に設け、上記濃縮水の酸化
還元電位を所定の値以下に維持することを特徴とする逆
浸透膜を用いた脱塩処理装置。
4. A chemical addition means for adding a reducing agent such as sodium bisulfite to the water to be treated, and a reverse osmosis for desalting the water to be treated after dechlorination by the reducing agent added by the chemical addition means. In a desalination apparatus equipped with a reverse osmosis means using a membrane, a method for removing dissolved oxygen in the water to be treated is provided.
A stage is provided on the upstream side of the reverse osmosis means, and a means for monitoring the oxidation-reduction potential of the concentrated water flowing out from the reverse osmosis means is provided on the downstream side of the reverse osmosis means to oxidize the concentrated water.
A desalination treatment apparatus using a reverse osmosis membrane, characterized in that the reduction potential is maintained below a predetermined value .
【請求項5】 上記被処理水の溶存酸素を除去する手段
として真空脱気手段を設けたことを特徴とする請求項4
に記載の逆浸透膜を用いた脱塩処理装置。
5. A method according to claim 4, characterized in that a vacuum degassing means as means for removing the dissolved oxygen in the water to be treated
A desalination treatment apparatus using the reverse osmosis membrane according to 1.
【請求項6】 上記被処理水の溶存酸素を除去する手段
として重亜硫酸ナトリウムを添加する添加手段を設けた
ことを特徴とする請求項4に記載の逆浸透膜を用いた脱
塩処理装置。
6. The desalination treatment apparatus using a reverse osmosis membrane according to claim 4 , wherein an addition means for adding sodium bisulfite is provided as a means for removing dissolved oxygen in the water to be treated.
JP13068596A 1996-04-27 1996-04-27 Desalination method and device using reverse osmosis membrane Expired - Fee Related JP3491268B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP13068596A JP3491268B2 (en) 1996-04-27 1996-04-27 Desalination method and device using reverse osmosis membrane

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP13068596A JP3491268B2 (en) 1996-04-27 1996-04-27 Desalination method and device using reverse osmosis membrane

Publications (2)

Publication Number Publication Date
JPH09290259A JPH09290259A (en) 1997-11-11
JP3491268B2 true JP3491268B2 (en) 2004-01-26

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JP4933734B2 (en) * 2005-01-14 2012-05-16 出光興産株式会社 Treatment of water containing persistent substances
AU2005206407A1 (en) * 2004-01-22 2005-08-04 Daicen Membrane-Systems Ltd. Method for treating raw water containing hardly decomposable substance
EP1890969A4 (en) * 2005-05-25 2008-10-01 Univ Murdoch Improved method for desalination
AU2006251862B2 (en) * 2005-05-25 2011-12-01 Curtin University Of Technology Improved method for desalination
JP5536783B2 (en) * 2008-09-25 2014-07-02 ヴェオリア・ウォーター・ソリューションズ・アンド・テクノロジーズ・サポート Method for treating seawater for the purpose of producing injection water for offshore oil drilling and corresponding apparatus
JP5339054B2 (en) * 2008-12-09 2013-11-13 株式会社ウェルシィ Water treatment method
JP5609174B2 (en) * 2010-03-12 2014-10-22 三浦工業株式会社 Water treatment system
JP5634250B2 (en) * 2010-12-18 2014-12-03 三菱重工業株式会社 Membrane monitoring method
CN102167453B (en) * 2011-01-05 2012-10-10 浙江省电力试验研究院 Method for controlling chlorine dioxide in desalting system based on ORP monitoring
JP6728857B2 (en) * 2016-03-25 2020-07-22 栗田工業株式会社 Reverse osmosis membrane device and operating method thereof
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