JP2000237555A - Method for sterilizing membrane - Google Patents
Method for sterilizing membraneInfo
- Publication number
- JP2000237555A JP2000237555A JP11104985A JP10498599A JP2000237555A JP 2000237555 A JP2000237555 A JP 2000237555A JP 11104985 A JP11104985 A JP 11104985A JP 10498599 A JP10498599 A JP 10498599A JP 2000237555 A JP2000237555 A JP 2000237555A
- Authority
- JP
- Japan
- Prior art keywords
- membrane
- water
- sulfuric acid
- reverse osmosis
- membrane separation
- 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.)
- Granted
Links
Landscapes
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は膜分離を行う際の、
特に逆浸透法による脱塩、分離、更には逆浸透法による
海水淡水化を行う際の、膜の殺菌方法に関するものであ
る。[0001] The present invention relates to a method for performing membrane separation.
In particular, the present invention relates to a method for sterilizing a membrane when performing desalination and separation by a reverse osmosis method and further desalination of seawater by a reverse osmosis method.
【０００２】[0002]
【従来の技術】膜による分離技術は、海水及びカン水の
淡水化、医療、工業用純水、超純水の製造、工業廃水処
理など幅広い分野に利用されている。これら膜分離にお
いて、微生物による分離装置の汚染は、得られる透過水
の水質悪化や、膜面上での微生物増殖あるいは微生物お
よびその代謝物の膜面への付着などによる膜の透過性、
分離性の低下をもたらす。このような重要な問題を回避
するため、膜分離装置の殺菌法が種々提案されている
が、一般的には殺菌剤を常時、あるいは間欠的に供給液
に添加する方法がとられている。殺菌剤としては、実績
があり、価格、操作面でも有利な塩素系殺菌剤を０．１
〜５０ｐｐｍ程度の濃度になるよう添加するのが最も一
般的である。ただし塩素系殺菌剤は逆浸透膜の化学的劣
化をもたらすため、該殺菌剤を使用した場合は逆浸透膜
に供給する前に、還元剤を用いて遊離塩素を還元する必
要がある。還元剤としては一般的に亜硫酸水素ナトリウ
ムを１〜１０倍当量添加する。これは残存殺菌剤を完全
に消去すると同時に、還元剤が溶存酸素とも反応するこ
とを考慮した濃度である。ところが、本方法で運転を続
けても膜性能の低下する場合があることから、このよう
な操作方法が微生物を殺菌するのに必ずしも充分ではな
いことが明らかになってきた。これについては、塩素を
添加することによって、供給液中に存在する有機炭素が
酸化され、微生物に分解されやすい化合物に変換される
という説もある（A. B. Hamida and I. Moch, jr., Des
alination & Water Reuse, 6/3, 40〜45, (1996).）
が、実証はされていない。そこで間欠的に亜硫酸水素ナ
トリウムを、通常５００ｐｐｍの濃度で添加することに
よって殺菌する方法が開発され、一般的に使用されるに
至ったが、本方法も場合によって有効とは言い難く、微
生物が膜に堆積することが次第に明らかになってきてい
る。2. Description of the Related Art Separation techniques using membranes are used in a wide range of fields such as desalination of seawater and canned water, medical treatment, production of industrial pure water and ultrapure water, and industrial wastewater treatment. In these membrane separations, contamination of the separation device by microorganisms causes deterioration of water quality of the obtained permeated water, permeability of the membrane due to growth of microorganisms on the membrane surface or adhesion of microorganisms and metabolites to the membrane surface,
This leads to a decrease in separability. In order to avoid such an important problem, various methods of sterilizing a membrane separation device have been proposed. In general, a method of constantly or intermittently adding a sterilizing agent to a feed solution has been adopted. As a disinfectant, a chlorine-based disinfectant that has a proven track record and is advantageous in terms of price and operation is 0.1%.
It is most common to add it to a concentration of about 50 ppm. However, a chlorine-based disinfectant causes chemical degradation of the reverse osmosis membrane. Therefore, when the disinfectant is used, it is necessary to reduce free chlorine using a reducing agent before supplying the reverse osmosis membrane. As a reducing agent, sodium bisulfite is generally added in an amount of 1 to 10 times equivalent. This is a concentration considering that the residual germicide is completely eliminated and at the same time the reducing agent also reacts with dissolved oxygen. However, it has become clear that such an operation method is not always sufficient to sterilize microorganisms, since the membrane performance may be reduced even if the operation is continued by this method. There is a theory that the addition of chlorine oxidizes the organic carbon present in the feed and converts it into compounds that are easily degraded by microorganisms (AB Hamida and I. Moch, jr., Des.
alination & Water Reuse, 6/3, 40-45, (1996).)
However, it has not been demonstrated. Therefore, a method of sterilizing by adding sodium bisulfite intermittently, usually at a concentration of 500 ppm has been developed and has been generally used. However, this method is also not effective in some cases, and microorganisms are not effectively used. It is becoming increasingly clear that they will accumulate on the surface.
【０００３】[0003]
【発明が解決しようとする課題】亜硫酸水素ナトリウム
の殺菌効果としては、供給液中の酸素を除去できるこ
と、ｐＨを低下させること、などが挙げられる。しかし
膜装置の運転に際して、亜硫酸水素ナトリウムの間欠添
加の殺菌が効果的とは言い難い現状である。本発明者ら
はその原因を究明し、中性〜弱アルカリ性で生息する一
般の好気性細菌にとって嫌気状態は、生育は押さえられ
ても死に至る環境ではなく、むしろｐＨの低下が最も殺
菌に有効であるという結論に達した。これは微生物学的
に見ても矛盾しない結論といえる。一方海水のように塩
濃度の高い供給液では、５００ｐｐｍという高濃度の亜
硫酸水素ナトリウムを添加しても、一般の細菌は死滅す
るほどｐＨが下がらないことが判明した。従って、より
低濃度の塩を含む供給液においても、亜硫酸水素ナトリ
ウムの殺菌効果が、嫌気状態になることが原因ではな
く、ｐＨの低下が効果的であり、高価な亜硫酸水素ナト
リウムを高濃度添加する必要はなく、単に硫酸など安価
な酸を添加してｐＨを低下させるだけで、充分殺菌でき
ることを見出し、本発明に到達したものである。The bactericidal effects of sodium bisulfite include the ability to remove oxygen from the feed and the reduction of pH. However, at the time of operation of the membrane device, sterilization by intermittent addition of sodium bisulfite is not currently effective. The present inventors investigated the cause, and the anaerobic state for general aerobic bacteria that live in neutral to weakly alkaline conditions is not an environment where death is suppressed even if growth is suppressed, but a decrease in pH is most effective for sterilization. Was reached. This is a microbiologically consistent conclusion. On the other hand, it has been found that in a feed solution having a high salt concentration such as seawater, even if a high concentration of sodium bisulfite as high as 500 ppm is added, the pH does not drop so as to kill general bacteria. Therefore, even in a feed solution containing a lower concentration of salt, the bactericidal effect of sodium bisulfite is not caused by the anaerobic state, the pH is effectively reduced, and expensive sodium bisulfite is added at a high concentration. The present inventors have found that it is possible to sufficiently sterilize simply by adding an inexpensive acid such as sulfuric acid to lower the pH, and have reached the present invention.
【０００４】[0004]
【課題を解決するための手段】本発明の目的は下記の構
成により達成される。即ち本発明は、「膜を有する膜分
離装置を用いた水の分離精製を行なうに際して、一部の
時間において、膜分離装置への供給液のｐＨを４以下と
する酸性水処理工程を有することを特徴とする膜の殺菌
方法。」、「膜を有する膜分離装置を用いて水を分離精
製する方法であって、前記の膜の殺菌方法の工程を含む
ことを有することを特徴とする水の分離精製方法。」、
「膜分離装置の前段に前処理装置が設置されており、前
処理装置に対して間欠的に塩素を供給することを特徴と
する前記水の分離精製方法。」、ならびに「膜分離装置
および膜分離装置への供給液に酸性水を供給する手段を
有することを特徴とする水処理装置。」からなるもので
ある。The object of the present invention is achieved by the following constitution. That is, the present invention provides a method for treating an aqueous solution using a membrane separation apparatus having a membrane, in which the pH of the liquid supplied to the membrane separation apparatus is set to 4 or less during a part of the time. A method for separating and purifying water using a membrane separation device having a membrane, comprising the steps of the method for sterilizing a membrane, comprising the steps of: Separation and purification method. ",
"The method for separating and purifying water, wherein a pretreatment device is provided at a stage preceding the membrane separation device and chlorine is intermittently supplied to the pretreatment device." A water treatment apparatus comprising means for supplying acidic water to the supply liquid to the separation apparatus. "
【０００５】[0005]
【発明の実施の形態】本発明において、膜分離装置とは
造水、濃縮、分離などの目的で、被処理液を加圧下で膜
モジュールに供給し、透過液と濃縮液に分離するための
装置をいう。膜モジュールには逆浸透膜モジュール、限
外ろ過膜モジュール、精密ろ過膜モジュールなどがあ
り、膜分離装置はそこで主に使用する膜モジュールの種
類によって逆浸透膜装置、限外ろ過膜装置、精密ろ過膜
装置に分けられるが、具体的には逆浸透膜装置が挙げら
れる。逆浸透膜装置は、通常は逆浸透膜エレメント、耐
圧容器、加圧ポンプなどで構成される。該逆浸透膜装置
に供給される被分離液は通常、殺菌剤、凝集剤、さらに
還元剤、ｐＨ調整剤などの薬液添加と凝集、沈殿、砂濾
過、ポリッシングろ過、活性炭濾過、精密ろ過、限外ろ
過、保安フィルターなどの前処理が行なわれる。例え
ば、海水の脱塩の場合には、海水を取込んだ後、沈殿池
で粒子などを分離し、またここで塩素などの殺菌剤を添
加して殺菌を行なう。さらに塩化鉄、ポリ塩化アルミニ
ウムなどの凝集剤を添加して砂濾過を行なう。濾液は貯
槽に貯められ、硫酸などでｐＨを調整した後高圧ポンプ
に送られる。この送液中に亜硫酸水素ナトリウムなどの
還元剤を添加して殺菌剤を消去し、保安フィルターを透
過した後、高圧ポンプで昇圧されて逆浸透モジュールに
供給される。ただし、これらの前処理は用いる供給液の
種類、用途に応じて適宜採用される。BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a membrane separation device is a device for supplying a liquid to be treated to a membrane module under pressure and separating it into a permeate and a concentrate for the purpose of water production, concentration and separation. A device. Membrane modules include reverse osmosis membrane modules, ultrafiltration membrane modules, microfiltration membrane modules, etc.Depending on the type of membrane module used there, reverse osmosis membrane devices, ultrafiltration membrane devices, microfiltration Although it is divided into membrane devices, a specific example is a reverse osmosis membrane device. The reverse osmosis membrane device usually includes a reverse osmosis membrane element, a pressure vessel, a pressure pump, and the like. The liquid to be separated supplied to the reverse osmosis membrane device is usually added with a chemical solution such as a bactericide, a coagulant, a reducing agent, a pH adjuster and the like, coagulated, sedimented, sand filtered, polished, activated carbon, microfiltered, Pretreatment such as external filtration and security filter is performed. For example, in the case of seawater desalination, after taking in seawater, particles and the like are separated in a sedimentation basin, and a sterilizing agent such as chlorine is added here to sterilize. Further, a coagulant such as iron chloride or polyaluminum chloride is added to carry out sand filtration. The filtrate is stored in a storage tank, adjusted to pH with sulfuric acid or the like, and then sent to a high-pressure pump. A reducing agent such as sodium hydrogen sulfite is added to the liquid to remove the germicide, and after passing through a security filter, the pressure is increased by a high-pressure pump and supplied to the reverse osmosis module. However, these pretreatments are appropriately adopted depending on the type of the supply liquid to be used and the application.
【０００６】ここで逆浸透膜とは、被分離混合液中の一
部の成分、例えば溶媒を透過させ他の成分を透過させな
い半透性の膜である。ナノフィルトレーション膜または
ルースＲＯ膜なども広い意味では逆浸透膜に含まれる。
その素材には酢酸セルロース系ポリマー、ポリアミド、
ポリエステル、ポリイミド、ビニルポリマーなどの高分
子素材がよく使用されている。またその膜構造は膜の少
なくとも片面に緻密層を持ち、緻密層から膜内部あるい
はもう片方の面に向けて徐々に大きな孔径の微細孔を有
する非対称膜、非対称膜の緻密層の上に別の素材で形成
された非常に薄い活性層を有する複合膜がある。膜形態
には中空糸、平膜がある。中空糸、平膜の膜厚は１０μ
ｍ〜１ｍｍ、中空糸の外径は５０μｍ〜４ｍｍである。
また平膜では非対称膜、複合膜は織物、編み物、不織布
などの基材で支持されていることが好ましい。しかし、
本発明の方法は、逆浸透膜の素材、膜構造や膜形態によ
らず利用することができ、いずれも効果がある。代表的
な逆浸透膜としては、例えば酢酸セルロース系やポリア
ミド系の非対称膜およびポリアミド系、ポリ尿素系の活
性層を有する複合膜などがあげられる。これらの中で
も、酢酸セルロース系の非対称膜、ポリアミド系の複合
膜に本発明の方法が有効であり、さらに芳香族系のポリ
アミド複合膜では効果が大きい（特開昭６２−１２１６
０３号公報、特開平８−１３８６５８号公報、米国特許
第４２７７３４４号明細書）。[0006] Here, the reverse osmosis membrane is a semipermeable membrane that allows some components in the liquid mixture to be separated, for example, a solvent to pass through but not other components. Nanofiltration membranes or loose RO membranes are also broadly included in reverse osmosis membranes.
The material is cellulose acetate polymer, polyamide,
Polymer materials such as polyester, polyimide, and vinyl polymer are often used. The membrane structure has a dense layer on at least one surface of the film, and an asymmetric film having fine pores having a large pore diameter gradually from the dense layer toward the inside of the film or the other surface. There are composite membranes with a very thin active layer formed of a material. The membrane form includes a hollow fiber and a flat membrane. The thickness of hollow fiber and flat membrane is 10μ
m to 1 mm, and the outer diameter of the hollow fiber is 50 μm to 4 mm.
In the case of a flat membrane, the asymmetric membrane and the composite membrane are preferably supported by a substrate such as a woven fabric, a knitted fabric, or a nonwoven fabric. But,
The method of the present invention can be used irrespective of the material, membrane structure and membrane form of the reverse osmosis membrane, and all are effective. Typical reverse osmosis membranes include, for example, a cellulose acetate-based or polyamide-based asymmetric membrane and a composite membrane having a polyamide-based or polyurea-based active layer. Among them, the method of the present invention is effective for cellulose acetate-based asymmetric membranes and polyamide-based composite membranes, and is particularly effective for aromatic polyamide-based composite membranes (Japanese Patent Application Laid-Open No. 62-1216).
No. 03, JP-A-8-138658 and U.S. Pat. No. 4,277,344).
【０００７】逆浸透膜モジュールとは、上記逆浸透膜を
実際に使用するために形態化したものであり、平膜はス
パイラル、チューブラー、プレート・アンド・フレーム
のモジュールに組み込んで、また中空糸は束ねた上でモ
ジュールに組み込んで使用することができるが、本発明
はこれらの逆浸透膜モジュールの形態に左右されるもの
ではない。[0007] A reverse osmosis membrane module is formed by actually using the above reverse osmosis membrane. The flat membrane is incorporated in a spiral, tubular, plate and frame module, and a hollow fiber is used. Can be used after being bundled and assembled into a module, but the present invention is not limited to the form of these reverse osmosis membrane modules.
【０００８】また、逆浸透膜モジュールはスパイラル形
状では供給水の流路材、透過水流路材などの部材を組み
込んでおり、これら部材の構成はいずれの物を用いても
良いが特に高濃度用、高圧用に設計されたモジュールで
効果がある（特開平９−１４１０６０号公報、特開平９
−１４１０６７号公報）。Further, the reverse osmosis membrane module incorporates members such as a feed water channel material and a permeated water channel material in a spiral shape, and any of these members may be used. It is effective in a module designed for high pressure (Japanese Patent Application Laid-Open Nos.
No. -141067).
【０００９】逆浸透膜装置の運転圧力は０．１ＭＰａ〜
１５ＭＰａであり、供給液の種類、運転方法などで適宜
使い分けられる。かん水や超純水など浸透圧の低い溶液
を供給液とする場合には比較的低圧で、海水淡水化や廃
水処理、有用物の回収などの場合には比較的高圧で使用
される。The operating pressure of the reverse osmosis membrane device is 0.1 MPa to
It is 15 MPa, and can be appropriately used depending on the kind of the supply liquid, the operation method and the like. A relatively low pressure is used when a solution having a low osmotic pressure such as brackish water or ultrapure water is used as a feed liquid, and a relatively high pressure is used for desalination of seawater, wastewater treatment, recovery of useful substances, and the like.
【００１０】逆浸透膜装置の運転温度は０℃から１００
℃の範囲であり、０℃よりも低いと供給液が凍結して使
用できず、１００℃よりも高い場合には供給液の蒸発が
起こり使用できない。[0010] The operating temperature of the reverse osmosis membrane device is from 0 ° C to 100 ° C.
If the temperature is lower than 0 ° C., the supply liquid is frozen and cannot be used. If the temperature is higher than 100 ° C., the supply liquid evaporates and cannot be used.
【００１１】また、分離装置の回収率は５から１００％
まで分離操作、装置に応じて設定することが出来る。逆
浸透膜装置の回収率は５から９８％の間で適宜選択する
ことが出来る。ただし、供給液や濃縮液の性状、濃度、
浸透圧に応じて前処理、運転圧力、を考慮しなければな
らない（特開平８−１０８０４８号公報）。例えば海水
淡水化の場合には、通常１０〜４０％、高効率の装置の
場合には４０〜７０％の回収率である。かん水淡水化や
超純水製造の場合には７０％以上、９０〜９５％の回収
率で運転することもできる。The recovery rate of the separation device is 5 to 100%.
Up to the separation operation and the device can be set. The recovery rate of the reverse osmosis membrane device can be appropriately selected from 5 to 98%. However, the properties, concentration,
Pretreatment and operating pressure must be considered according to the osmotic pressure (Japanese Patent Laid-Open No. 8-108048). For example, in the case of seawater desalination, the recovery rate is usually 10 to 40%, and in the case of a highly efficient apparatus, the recovery rate is 40 to 70%. In the case of brackish water desalination or ultrapure water production, it can be operated at a recovery rate of 70% or more and 90 to 95%.
【００１２】逆浸透装置の構成は主に高圧ポンプと逆浸
透膜モジュールからなるが、高圧ポンプは装置の運転圧
力に応じて最適のポンプを選定することができる。The structure of the reverse osmosis device mainly comprises a high-pressure pump and a reverse osmosis membrane module, and the optimum high-pressure pump can be selected according to the operating pressure of the device.
【００１３】また、逆浸透膜モジュールの配列は１段で
使用することもできるが供給水に対して直列、並列に多
段に配列することが出来る。直列に配列する場合は逆浸
透膜モジュールの間に昇圧ポンプを設置することが出来
る。海水淡水化の直列の配列では装置コストの観点から
特に２段の配列が好ましく、直列に配列したモジュール
の間に昇圧ポンプを設置して供給液を１．０〜５．０Ｍ
Ｐａ程度、昇圧して後段のモジュールに供給することが
好ましい（特開平８−１０８０４８号公報）。供給液に
対して直列に配列した場合には膜モジュールと供給水が
接触する時間が長いので本発明の方法の効果が大きい。
さらに、逆浸透膜モジュールは透過水に対して直列に配
列することもできる。透過水の水質が不十分な場合や透
過水中の溶質成分を回収したい場合には好ましい方法で
ある。透過水に対して直列に配列する場合には、間にポ
ンプを設置し、透過水を再び加圧するか、前段で余分に
圧力をかけておき背圧をかけて膜分離することが出来
る。透過水に対して直列に配置する場合には後ろの膜モ
ジュール部分の殺菌を行うために酸の添加装置を膜モジ
ュールと膜モジュールの間に設ける。The reverse osmosis membrane modules can be arranged in one stage, but can be arranged in series or in parallel with the supply water in multiple stages. When arranged in series, a booster pump can be installed between the reverse osmosis membrane modules. In the seawater desalination series arrangement, a two-stage arrangement is particularly preferable from the viewpoint of the equipment cost. A booster pump is installed between the series-arranged modules to supply a supply liquid of 1.0 to 5.0M.
It is preferable to increase the pressure by about Pa and supply it to the subsequent module (JP-A-8-108048). When arranged in series with the supply liquid, the time of contact between the membrane module and the supply water is long, and the effect of the method of the present invention is large.
Further, the reverse osmosis membrane modules can be arranged in series with the permeate. This is a preferable method when the quality of the permeated water is insufficient or when it is desired to recover solute components in the permeated water. When the permeated water is arranged in series, a pump can be installed between the permeated water and the permeated water can be pressurized again, or extra pressure can be applied in the previous stage and back pressure can be applied to perform membrane separation. In the case of disposing in series with the permeated water, an acid addition device is provided between the membrane modules to sterilize the rear membrane module.
【００１４】逆浸透膜の装置においては供給水のうち膜
を透過しなかった部分は濃縮水として膜モジュールから
取り出される。この濃縮水は用途に応じて処理した後に
廃棄したり、さらに他の方法で濃縮することも可能であ
る。また、濃縮水はその一部又は全てを供給水に循環す
ることもできる。膜を透過した部分においても用途に応
じて廃棄したり、そのまま利用したり、あるいは供給水
にその一部又は全てを循環することができる。In the reverse osmosis membrane device, a portion of the feed water that has not passed through the membrane is taken out of the membrane module as concentrated water. The concentrated water can be treated and discarded according to the intended use, or can be further concentrated by another method. Also, part or all of the concentrated water can be circulated to the feed water. The portion that has permeated the membrane can also be discarded according to the application, used as it is, or part or all of it can be circulated to the supply water.
【００１５】一般に逆浸透装置の濃縮水は圧力エネルギ
ーを有しており、運転コストの低減化のためにはこのエ
ネルギーを回収することが好ましい。エネルギー回収の
方法としては任意の部分の高圧ポンプに取り付けたエネ
ルギー回収装置で回収することもできるが、高圧ポンプ
の前後や、モジュールの間に取り付けた専用のタービン
タイプのエネルギー回収ポンプで回収することが好まし
い。また、膜分離装置の処理能力は一日当たり水量で
０．５ｍ3〜１００万ｍ3の装置である。Generally, the concentrated water of the reverse osmosis device has pressure energy, and it is preferable to recover this energy in order to reduce operating costs. As an energy recovery method, it is possible to recover energy using an energy recovery device attached to any part of the high-pressure pump.However, use a dedicated turbine-type energy recovery pump installed before and after the high-pressure pump or between modules. Is preferred. Further, the processing capacity of the membrane separation device is a device having a water volume of 0.5 m 3 to 1,000,000 m 3 per day.
【００１６】また本発明が使用される分離装置では、装
置配管は出来るだけ滞留部の少ない構造とすることが好
ましい。Further, in the separation apparatus in which the present invention is used, it is preferable that the apparatus piping has a structure having as few stagnation portions as possible.
【００１７】本発明において、ｐＨを４以下にすること
は膜に対して高い殺菌効果を提供する上で極めて重要で
あり、特に海水を供給水として使用する膜濾過において
この効果は顕著である。微生物の死滅するｐＨは個々の
微生物に特有であり、例えば大腸菌の場合生育の下限は
ｐＨ４．６であるが、死滅はｐＨ３．４以下でおこる。
一方海水中にも多種多様の微生物が存在し、それぞれ死
滅するｐＨが異なる。しかし、本発明において、多種の
生菌を含む海水をｐＨ４以下に一定時間保持すれば、５
０〜１００％を死滅させることが可能である。またｐＨ
３．９以下の酸性度、さらにｐＨ３．７以下の酸性度
も、海水由来の菌を死滅させるという観点で好ましい範
囲である。ｐＨを所望の状態にするためには、通常は酸
を用いる。酸としては、有機酸、無機酸いずれを用いて
も差し支えないが、経済的な面を考えると、硫酸を用い
ることが好ましい。また硫酸の添加量は供給液の塩濃度
に比例する。例えば加圧滅菌（１２０℃、１５分）した
生理食塩水（食塩濃度０．９％）では硫酸５０ｐｐｍの
添加でｐＨ３．２まで低下するが、加圧滅菌（１２０
℃、１５分）した３カ所の海水および市販の人工海水
（塩濃度約３．５％）では、硫酸を１００ｐｐｍ添加し
た場合でもｐＨ５．０〜５．８であった。これは主に海
水のＭアルカリ度によって大きく変動すると考えられ
る。さらにｐＨ４以下にするためには、１２０ｐｐｍ以
上の添加が好ましい。最大添加量は経済性や配管等設備
への影響を考えると、４００ｐｐｍ、更に好ましくは３
００ｐｐｍである。なお上記の海水、人工海水への硫酸
添加濃度を更に１５０ｐｐｍ、２００ｐｐｍとすると、
それぞれｐＨ３．２〜３．６、ｐＨ２．８〜２．９と、
添加濃度が高くなるに従ってｐＨ変動は減少する。In the present invention, setting the pH to 4 or less is extremely important in providing a high bactericidal effect on the membrane, and this effect is particularly remarkable in membrane filtration using seawater as feed water. The pH at which microorganisms die is specific to individual microorganisms. For example, in the case of Escherichia coli, the lower limit of growth is pH 4.6, but killing occurs at pH 3.4 or less.
On the other hand, a variety of microorganisms also exist in seawater, and the pH at which they die is different from each other. However, in the present invention, if seawater containing various viable bacteria is maintained at pH 4 or less for a certain period of time, 5
It is possible to kill 0-100%. Also pH
An acidity of 3.9 or less and a pH of 3.7 or less are also preferable ranges from the viewpoint of killing bacteria derived from seawater. To bring the pH to a desired state, an acid is usually used. As the acid, either an organic acid or an inorganic acid may be used, but from the viewpoint of economy, it is preferable to use sulfuric acid. The amount of sulfuric acid added is proportional to the salt concentration of the feed solution. For example, in a physiological saline solution (0.9% salt concentration) sterilized by autoclaving (120 ° C., 15 minutes), the pH is lowered to 3.2 by adding 50 ppm of sulfuric acid.
(3 ° C., 15 minutes), and in three places of seawater and commercially available artificial seawater (salt concentration: about 3.5%), the pH was 5.0 to 5.8 even when 100 ppm of sulfuric acid was added. It is considered that this largely varies mainly depending on the M alkalinity of seawater. In order to further reduce the pH to 4 or less, it is preferable to add 120 ppm or more. The maximum addition amount is 400 ppm, more preferably 3 ppm, in consideration of the economy and the effect on facilities such as piping.
00 ppm. In addition, when the sulfuric acid addition concentration in the above seawater and artificial seawater is further set to 150 ppm and 200 ppm,
PH 3.2 to 3.6, pH 2.8 to 2.9, respectively
The pH fluctuation decreases as the added concentration increases.
【００１８】本発明の膜の殺菌は、被処理水が前処理を
終えて膜モジュールに供給される工程において、間欠的
に実施される。その添加時間、添加頻度は、使用場所、
使用条件などで大きく異なる。例えば、０．５〜２．５
時間の添加を１日ごと、１週間ごと、１ヶ月ごと、と言
った間隔で行うことができる。これらは膜の透過水量の
減少、濃縮液の生菌数や含有有機炭素の増加、膜圧の上
昇などによって変動する。また非連続使用の場合は、休
止時に膜を浸漬することで実施することも可能である。The sterilization of the membrane of the present invention is carried out intermittently in the process in which the water to be treated is supplied to the membrane module after the pretreatment. The time and frequency of addition depend on the place of use,
It varies greatly depending on conditions of use. For example, 0.5 to 2.5
The addition of time can be done at daily, weekly, monthly, etc. intervals. These fluctuate due to a decrease in the amount of permeated water through the membrane, an increase in the number of viable bacteria in the concentrated solution, an increase in the amount of organic carbon contained, and an increase in the membrane pressure. In the case of non-continuous use, it can be carried out by immersing the membrane at rest.
【００１９】さらに、本願の殺菌方法は、塩素などの他
の殺菌方法と併用することも可能である。Further, the sterilization method of the present invention can be used in combination with another sterilization method such as chlorine.
【００２０】本発明の膜の殺菌方法は、単に膜分離装置
のみならず、膜分離装置を一部に含む水の分離システム
にも適用できる。例えば以下に示す構成のシステムであ
る。 Ａ．取水装置。これは原水を取り込む装置であって、通
常取水ポンプ、薬品注入設備などで構成される。 Ｂ．取水装置に連通した前処理装置。これは分離膜装置
に供給する水を前処理して所望の程度まで精製するもの
である。例えば以下の順に構成することができる。 Ｂ−１ 凝集濾過装置。 Ｂ−２ ポリッシング濾過装置。ただし前記Ｂ−１、Ｂ
−２の替わりに限外濾過装置や精密濾過装置を用いても
良い。 Ｂ−３ 凝集剤、殺菌剤、ｐＨ調整剤などの薬品注入設
備。 Ｃ．前処理装置に連通し必要に応じて設置される中間
槽。これは水量調節、水質の緩衝作用の機能を提供する
ものである。 Ｄ．Ｃを設置する場合には中間槽に連通し、またはＣを
設置しない場合には前処理装置から連通したフィルタ
ー。これは膜分離装置に供給される水の固形不純物を除
去する。 Ｅ．膜分離装置。高圧ポンプおよび分離膜モジュールか
らなる。膜分離装置は複数設置して、これらを並列に設
置しても、直列に設置してもよい。直列に設定する場合
には、後段の分離膜装置に供給する水圧を上げるための
ポンプを膜分離装置間に設けることができる。 Ｆ．膜分離装置の膜透過側出口部分に連通した後処理装
置。以下の装置が例示される。 Ｆ−１ 脱気装置。これは脱炭酸の機能を有するもので
ある。 Ｆ−２ カルシウム塔。 Ｆ−３ 塩素注入。 Ｇ．膜分離装置の原水側出口部分に連通した後処理装
置。以下の装置が例示される。 Ｇ−１ ｐＨを４とした供給液を処理する装置。例えば
中和装置。 Ｇ−２ 放流設備。 Ｈ．その他、廃水の処理装置を適宜設けても良い。The method for sterilizing a membrane of the present invention can be applied not only to a membrane separation device but also to a water separation system partially including the membrane separation device. For example, the system has the following configuration. A. Intake device. This is a device that takes in raw water, and is usually composed of a water intake pump, a chemical injection facility, and the like. B. A pretreatment device connected to the water intake device. In this method, water to be supplied to a separation membrane device is pretreated and purified to a desired degree. For example, they can be configured in the following order. B-1 Aggregation filtration device. B-2 Polishing filtration device. However, B-1 and B
An ultrafiltration device or a microfiltration device may be used instead of -2. B-3 Chemical injection equipment such as a flocculant, a bactericide, and a pH adjuster. C. An intermediate tank that communicates with the pretreatment device and is installed as needed. This provides functions of water volume control and water quality buffering. D. A filter connected to the intermediate tank when C is installed, or from a pretreatment device when C is not installed. This removes solid impurities of the water supplied to the membrane separator. E. FIG. Membrane separation device. It consists of a high-pressure pump and a separation membrane module. A plurality of membrane separation devices may be installed, and these may be installed in parallel or in series. In the case of setting in series, a pump for increasing the water pressure supplied to the subsequent separation membrane device can be provided between the membrane separation devices. F. A post-processing device that communicates with the outlet of the membrane permeation side of the membrane separation device. The following devices are exemplified. F-1 Deaerator. This has a function of decarboxylation. F-2 Calcium tower. F-3 Chlorine injection. G. FIG. Post-treatment device that communicates with the raw water side outlet of the membrane separation device. The following devices are exemplified. G-1 An apparatus for processing a supply liquid having a pH of 4. For example, a neutralization device. G-2 Discharge facility. H. In addition, a wastewater treatment device may be appropriately provided.
【００２１】このような装置においては任意のところに
ポンプを設けることができる。またｐＨを４と以下とす
るために薬剤または薬剤の溶液を添加するのは、Ａの取
水装置、Ｂの前処理装置において、もしくは前処理装置
の前、または、Ｄのフィルターの前、もしくはフィルタ
ーの後であることが好ましい。In such an apparatus, a pump can be provided at an arbitrary position. The addition of the drug or the solution of the drug to make the pH of 4 or less is performed in the water intake device of A, the pretreatment device of B, or before the pretreatment device, or before the filter of D, or the filter. Is preferably after.
【００２２】また、本願発明の効果をより高めるため
に、酸添加装置は自動制御できるものが好ましく、適宜
注入量をコントロールできるポンプを備え付けているこ
とが好ましい。また、コントロールのために装置内の適
当な箇所に供給液、濃縮液のｐＨを測定する装置を備え
付けていることが好ましい。また、間欠的添加をコント
ロールするために時間を測定できる装置を有しているこ
とが好ましい。さらに好ましくは自動運転できる自動制
御装置を具備してなることが好ましい。In order to further enhance the effects of the present invention, it is preferable that the acid addition device can be automatically controlled, and it is preferable that a pump capable of appropriately controlling the injection amount is provided. Further, it is preferable that a device for measuring the pH of the supply liquid or the concentrated solution is provided at an appropriate place in the device for control. Further, it is preferable to have a device capable of measuring time in order to control intermittent addition. More preferably, it is preferable to have an automatic control device capable of automatic operation.
【００２３】本願発明の装置はその構成部材、例えば配
管、バルブなどはｐＨ４以下の条件で変化しにくいもの
を使用する。The components of the apparatus of the present invention, such as pipes and valves, are those which are hardly changed under the condition of pH 4 or less.
【００２４】ｐＨを４以下とすることによって高い殺菌
効果が得られると同時に、配管内のスケールを除去でき
るという効果も得ることができる。さらには、塩素等の
酸化物による膜劣化を防止するために亜硫酸水素ナトリ
ウムを添加する場合があるが、その添加量が膜面上に付
着する微生物（イオウ細菌などが考えられる）、金属塩
等の影響で、増加するような場合に、本発明の酸性水に
よって膜分離装置を処理によってその添加量を著しく低
減できる効果も得ることができる。By setting the pH to 4 or less, a high sterilizing effect can be obtained, and at the same time, an effect that scale in the pipe can be removed can be obtained. Furthermore, sodium bisulfite may be added to prevent film deterioration due to oxides such as chlorine. However, the amount of addition may be limited to microorganisms (such as sulfur bacteria) that adhere to the film surface, metal salts, and the like. In the case where the amount increases due to the effect of the above, the effect of remarkably reducing the amount of the membrane separation device to be treated by the acidic water of the present invention can be obtained.
【００２５】本発明の方法は、膜を用いる分離に好適に
使用できるが、特に水溶液の分離に効果が大きい。さら
に、分離の用途としては精密ろ過膜を用いた液体と固形
分の分離・濃縮、限外ろ過膜を用いた濁質分の分離・濃
縮、逆浸透膜を用いた溶解成分の分離・濃縮に効果があ
る。特に、海水の淡水化や、かん水の淡水化、工業用水
の製造、超純水、純水の製造、医薬用水の製造、食品の
濃縮、水道原水の除濁、水道における高度処理で効果が
大きい。従来の酸化性殺菌剤で分解しやすい有機物、等
を分離・濃縮する場合にも、殺菌による分解なしで濃
縮、回収することができ、本発明の方法の効果が大き
い。また、飲料水製造の場合には塩素殺菌によるトリハ
ロメタン発生を防止できる効果がある。特に本発明の殺
菌方法は海水に起因する菌に対して有効である。The method of the present invention can be suitably used for separation using a membrane, but is particularly effective for separating an aqueous solution. Separation and concentration of liquids and solids using microfiltration membranes, separation and concentration of suspended matter using ultrafiltration membranes, and separation and concentration of dissolved components using reverse osmosis membranes effective. Particularly effective in seawater desalination, brackish water desalination, industrial water production, ultrapure water, pure water production, pharmaceutical water production, food concentration, turbidity of tap water, and advanced treatment in tap water. . Even in the case of separating and concentrating organic substances which are easily decomposed by a conventional oxidizing bactericide, it can be concentrated and recovered without decomposition by sterilization, and the effect of the method of the present invention is great. In addition, in the case of producing drinking water, there is an effect that the generation of trihalomethane due to chlorine sterilization can be prevented. In particular, the sterilization method of the present invention is effective against bacteria caused by seawater.
【００２６】一般に、膜分離装置より前に供給水を処理
する工程、例えば前記Ａ〜Ｄの装置における殺菌は、い
ずれかのところで、従来の技術の欄で説明したとおり塩
素系殺菌剤の連続、又は間欠注入が実施されている。こ
の方法により供給水は耐性菌が出現しない限りほぼ完全
に殺菌できるが、塩素系殺菌剤が通常は逆浸透膜の化学
的劣化をもたらすため、膜分離装置の手前で亜硫酸水素
ナトリウムを代表とする還元剤を添加する。しかし、還
元剤により塩素を除去した後の供給水は微生物が容易に
繁殖できる状態となる。しかも殺菌剤添加前の原海水の
ように種々雑多な微生物ではなく、かなり選別された微
生物群がそこに存在し、その中には耐酸性菌も多く含ま
れることになる。また亜硫酸水素ナトリウムを代表とす
る還元剤添加が不充分な場合は、塩素系殺菌剤が完全に
は消去できずに膜の劣化をもたらす場合があるが、一方
過剰添加することによってある種の細菌が繁殖すること
もある。従って本発明の膜分離装置の供給液に、硫酸な
どの酸を添加して殺菌方法を実施する際には、塩素系殺
菌剤を添加しないことが好ましいが、この場合は逆に前
の処理工程で生物が繁殖することになる。In general, the step of treating the feed water before the membrane separation apparatus, for example, the sterilization in the above-mentioned apparatuses A to D, may be performed by any of the steps described in the section of the prior art, such as the continuation of the chlorine-based sterilizing agent. Or intermittent injection has been performed. The feed water can be almost completely sterilized by this method as long as resistant bacteria do not appear, but since chlorine-based germicides usually cause chemical degradation of the reverse osmosis membrane, sodium bisulfite is represented before the membrane separation device. Add the reducing agent. However, the supply water from which chlorine has been removed by the reducing agent is in a state where microorganisms can easily propagate. Moreover, rather than various microorganisms as in the raw seawater before the addition of the fungicide, a considerably selected group of microorganisms exists there, and many acid-resistant bacteria are also contained therein. If the addition of a reducing agent such as sodium bisulfite is insufficient, the chlorine-based disinfectant may not be completely eliminated and may cause deterioration of the film. May breed. Therefore, when the sterilization method is carried out by adding an acid such as sulfuric acid to the feed solution of the membrane separation device of the present invention, it is preferable not to add a chlorine-based germicide. The creature will breed.
【００２７】この問題に対しては、間欠的に、前工程に
おいて塩素系殺菌剤、および膜分離装置への供給前に還
元剤を注入することによって、非注入時に前処理工程の
配管や濾過槽等に付着、堆積した生物を殺菌することで
解決される。この方法によれば、同時に膜の劣化を防止
するためにも有効である。塩素系殺菌剤の時間的な注入
間隔は原海水の水質、すなわち生物の存在状態に合わせ
て、１日〜６ヶ月に１回、３０分〜２時間程度実施すれ
ばよい。この塩素系殺菌剤の添加時期に合わせて、かつ
塩素系添加剤を含有する水の移動にともなった時間に、
前処理装置と膜分離装置との間に還元剤を供給して、塩
素系殺菌剤を非活性化するのがよい。さらに、その時期
に合わせて膜分離装置の供給液に、本発明の硫酸などの
酸を添加して、膜分離装置の殺菌を実施するのがよい。
この様な、前処理工程に対する間欠的塩素殺菌剤注入方
法は、連続的な殺菌剤の注入に対して、薬品代など処理
費の著しい低減効果をもたらすが、これは本発明の酸に
よる膜分離装置の殺菌方法が存在してはじめて達成され
るもので、従来の高濃度の亜硫酸水素ナトリウム添加に
よる膜の殺菌方法では、殺菌効果が不十分なため到底実
施できるものではなかったのである。To solve this problem, by intermittently injecting the chlorine-based disinfectant in the pre-process and the reducing agent before supplying to the membrane separation device, the pipes and the filtration tank in the pre-treatment process can be intermittently injected. The problem is solved by disinfecting the organisms that have adhered and deposited on the surface. According to this method, it is also effective to prevent the deterioration of the film at the same time. The time interval of the chlorine-based disinfectant injection may be about once every 1 day to 6 months, about 30 minutes to 2 hours, depending on the quality of the raw seawater, that is, the state of living organisms. In accordance with the time of addition of the chlorine-based disinfectant, and during the time accompanying the movement of water containing the chlorine-based additive,
It is preferable to supply a reducing agent between the pretreatment device and the membrane separation device to deactivate the chlorine-based germicide. Further, it is preferable that the acid such as sulfuric acid of the present invention is added to the supply liquid of the membrane separation device at the same time to sterilize the membrane separation device.
Such an intermittent chlorine disinfectant injection method for the pretreatment step has a remarkable effect of reducing treatment costs such as a chemical cost for continuous disinfectant injection. It can be achieved only when there is a method for disinfecting the apparatus, and the conventional method for disinfecting a membrane by adding high-concentration sodium bisulfite could not be carried out at all because the disinfection effect was insufficient.
【００２８】[0028]
【実施例】以下に実施例を挙げて本発明を具体的に説明
するが、本発明はこれらの実施例によりなんら限定され
るものではない。 実施例１ 加圧滅菌（１２０℃、１５分）後硫酸を添加してｐＨを
調整した生理食塩水（食塩濃度０．９％）に、大腸菌
（Escherichia coli K12 IFO 3301）の懸濁液をそれぞ
れ一定量ずつ加え、２０℃で一定時間保持した後に残存
する生菌数を添加時の生菌数で割って生存率を求めた。
この結果、硫酸１０ｐｐｍの添加（ｐＨ４．７）では
２．５時間保持しても生存率は９０％以上であったが、
５０ｐｐｍの添加（ｐＨ３．２）では、０．５時間の保
持で生存率が９０％、１時間で２０％、２．５時間で１
％以下となった。硫酸を１００ｐｐｍ添加すれば、０．
５時間の保持で１％以下の生存率となった。 実施例２ 加圧滅菌（１２０℃、１５分）後硫酸を添加してｐＨを
調整した市販の３．５％人工海水に、実施例１で使用し
た大腸菌、海水の脱塩に使用した逆浸透膜の堆積物懸濁
液、およびその懸濁液から分離した中で最も数の多かっ
た未同定細菌をそれぞれ一定量ずつ加え、２０℃で一定
時間保持した後の生存率を求めて表２の結果を得た。な
お比較のため、硫酸に代えて亜硫酸水素ナトリウムを５
００ｐｐｍ添加した結果も列記した。表１から、ｐＨ
４．０以下に０．５時間以上保持することによって極め
て高い殺菌効果が提供されることが理解できる。EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Example 1 A suspension of Escherichia coli K12 IFO 3301 was placed in a physiological saline solution (salt concentration: 0.9%) adjusted to pH by adding sulfuric acid after autoclaving (120 ° C., 15 minutes). Viability was determined by dividing the number of viable cells remaining after keeping the solution at 20 ° C. for a certain period of time by the number of viable cells at the time of addition.
As a result, with the addition of sulfuric acid 10 ppm (pH 4.7), the survival rate was 90% or more even after holding for 2.5 hours.
With the addition of 50 ppm (pH 3.2), the survival rate was 90% for 0.5 hours, 20% for 1 hour, and 1% for 2.5 hours.
% Or less. If 100 ppm of sulfuric acid is added, 0.1% is added.
The retention of 5 hours resulted in a survival rate of 1% or less. Example 2 Commercially available 3.5% artificial seawater adjusted to pH by adding sulfuric acid after autoclaving (120 ° C., 15 minutes) and reverse osmosis used for desalination of Escherichia coli used in Example 1 and seawater A fixed amount of each of the membrane sediment suspension and the largest number of unidentified bacteria separated from the suspension was added, and the survival rate after holding at 20 ° C. for a fixed time was determined. The result was obtained. For comparison, 5% sodium bisulfite was used instead of sulfuric acid.
The results of adding 00 ppm are also listed. From Table 1, the pH
It can be understood that an extremely high bactericidal effect is provided by keeping the temperature at 4.0 or less for 0.5 hour or more.
【００２９】[0029]
【表１】 [Table 1]
【００３０】実施例３ 海水を供給水として用い、ポリアミドからなる逆浸透膜
を用いた膜分離装置２機を同時並行で運転し、淡水への
逆浸透濾過を行った。このうち１機は、前処理後の海水
に硫酸を加えてｐＨを３．５〜４．０に調整した供給水
を、１日に３０分通水した。１ヶ月間連続運転を行った
結果、硫酸を加えなかったほうの装置は膜圧の上昇が見
られたが、硫酸を加えたほうは変化がなかった。また通
常運転時に濾過濃縮水の生菌数を測定したところ、硫酸
処理を行った後の装置では、硫酸処理をしていない装置
と比較して、１／１００以下に減少していた。 実施例４ 寒天塗抹法で測定した生菌数が１ｍｌあたり２００個で
ある海水を供給水として用い、ポリアミドからなる逆浸
透膜を用いた膜分離装置を運転して逆浸透分離を行っ
た。前処理工程において供給海水に塩素の残存濃度が１
ｐｐｍとなるよう塩素系殺菌剤を連続添加し、逆浸透膜
モジュールの手前で亜硫酸水素ナトリウムを添加した。
亜硫酸水素ナトリウムの添加濃度は、逆浸透膜モジュー
ルから排出されるブライン中の残存濃度が１ｐｐｍ以上
になるように調節した。亜硫酸水素ナトリウムの消費量
は当初５ｐｐｍであったのが、１０日間連続運転を行っ
た結果、３５ｐｐｍまで上昇した。この間膜差圧は約
０．０１ＭＰａ上昇した。硫酸を加えてｐＨを３〜４に
調整した供給水を、１日３０分通水したところ、亜硫酸
水素ナトリウムの消費量は８ｐｐｍまで減少した。その
時の膜差圧は０．０１ＭＰａ上昇した状態を維持してい
た。 実施例５ 寒天塗抹法で測定した生菌数が１ｍｌあたり２０万個で
ある海水を供給水として用い、ポリアミドからなる逆浸
透膜を用いた膜分離装置を運転して逆浸透分離を行っ
た。前処理工程では塩素系殺菌剤を１ｐｐｍ、脱塩素剤
として亜硫酸水素ナトリウムを６ｐｐｍ、それぞれ連続
注入し、膜分離工程では亜硫酸水素ナトリウム５００ｐ
ｐｍを１週間に１時間添加した。約１ヶ月経過後膜差圧
は約０．０２ＭＰａ上昇した。同じ装置を用いて、前処
理工程では、塩素系殺菌剤１ｐｐｍを１日１時間、亜硫
酸水素ナトリウム６ｐｐｍを１日３時間それぞれ間欠的
に添加し、膜分離工程では硫酸を加えてｐＨ４に調整し
た供給水を１日１時間通水した。約１ヶ月経過しても膜
差圧はほとんど変化しなかった。 実施例６ 前処理工程までは実施例５の後半と同じ条件で、膜分離
工程での殺菌を行わないで５０日間運転した結果、膜差
圧が０．０３ＭＰａ上昇した。この時点から膜分離工程
で硫酸を加えてｐＨ３に調整した供給水を１日１時間通
水した結果、８日後には膜差圧が０．０１５ＭＰａ低下
した。さらに膜分離工程での殺菌を中止して２０日間運
転した結果、膜差圧が０．０２ＭＰａ上昇した。この時
点から膜分離工程で硫酸を加えてｐＨ４に調整した供給
水を１日１時間通水した結果、１２日後には膜差圧が
０．０１２ＭＰａ低下した。Example 3 Using seawater as feed water, two membrane separators using a reverse osmosis membrane made of polyamide were operated simultaneously in parallel to perform reverse osmosis filtration to fresh water. Among these, one machine supplied sulfuric acid to seawater after pretreatment to adjust the pH to 3.5 to 4.0, and supplied water for 30 minutes a day. As a result of continuous operation for one month, the membrane pressure of the apparatus without addition of sulfuric acid was increased, but the apparatus with addition of sulfuric acid did not change. In addition, when the viable cell count of the filtered concentrated water was measured during normal operation, the device after the sulfuric acid treatment was reduced to 1/100 or less of the device without the sulfuric acid treatment. Example 4 Reverse osmosis separation was performed by using a seawater having a viable cell count of 200 per 1 ml as measured by an agar smear method as a feed water and operating a membrane separation apparatus using a reverse osmosis membrane made of polyamide. In the pretreatment process, the residual concentration of chlorine in the supplied seawater is 1
A chlorine-based germicide was continuously added so as to be ppm, and sodium bisulfite was added just before the reverse osmosis membrane module.
The concentration of sodium bisulfite added was adjusted so that the residual concentration in the brine discharged from the reverse osmosis membrane module was 1 ppm or more. The consumption amount of sodium bisulfite was 5 ppm at the beginning, but increased to 35 ppm as a result of continuous operation for 10 days. The transmembrane pressure increased by about 0.01 MPa. When feed water whose pH was adjusted to 3 to 4 by adding sulfuric acid was passed for 30 minutes a day, the consumption of sodium bisulfite was reduced to 8 ppm. The transmembrane pressure at that time was maintained in a state of increasing by 0.01 MPa. Example 5 Reverse osmosis separation was performed by using a seawater having a viable cell count of 200,000 per 1 ml as measured by an agar smear method as a feed water and operating a membrane separation apparatus using a reverse osmosis membrane made of polyamide. In the pretreatment step, 1 ppm of a chlorine-based disinfectant and 6 ppm of sodium bisulfite as a dechlorinating agent were continuously injected, and in the membrane separation step, 500 p of sodium bisulfite.
pm was added for one hour per week. After about one month, the transmembrane pressure increased by about 0.02 MPa. Using the same apparatus, in the pretreatment step, 1 ppm of a chlorine-based disinfectant was added intermittently for 1 hour per day, and 6 ppm of sodium bisulfite was added intermittently for 3 hours per day. In the membrane separation step, sulfuric acid was added to adjust the pH to 4. Feed water was passed for one hour a day. Even after about one month, the transmembrane pressure hardly changed. Example 6 As a result of operating for 50 days under the same conditions as in the latter half of Example 5 up to the pretreatment step without performing sterilization in the membrane separation step, the membrane differential pressure increased by 0.03 MPa. From this point, feed water adjusted to pH 3 by adding sulfuric acid in the membrane separation step was passed for 1 hour per day. As a result, the membrane differential pressure decreased 0.015 MPa after 8 days. Furthermore, as a result of stopping the sterilization in the membrane separation step and operating for 20 days, the membrane differential pressure increased by 0.02 MPa. From this point, feed water adjusted to pH 4 by adding sulfuric acid in the membrane separation step was passed for one hour a day, and as a result, the membrane differential pressure decreased by 0.012 MPa after 12 days.
【００３１】[0031]
【発明の効果】膜分離装置を用いて水を精製する際に、
膜面あるいは膜付近に存在する微生物を殺菌する方法と
して、従来用いられてきた高濃度亜硫酸水素ナトリウム
の間欠添加に比べ、本発明の方法によれば確実な殺菌が
可能となる。According to the present invention, when water is purified using a membrane separation device,
As a method for disinfecting microorganisms existing on or near the membrane surface, the method of the present invention enables more reliable disinfection than the conventionally used intermittent addition of high-concentration sodium bisulfite.
─────────────────────────────────────────────────────
────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成１１年８月２６日（１９９９．８．２
６）[Submission date] August 26, 1999 (1999.8.2
6)
【手続補正１】[Procedure amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】特許請求の範囲[Correction target item name] Claims
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【特許請求の範囲】[Claims]
【手続補正２】[Procedure amendment 2]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】０００４[Correction target item name] 0004
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【０００４】[0004]
【課題を解決するための手段】本発明の目的は下記の構
成により達成される。即ち本発明は、「膜分離装置を用
いて水を分離精製するにあたり、膜分離装置へ供給する
供給水のｐＨを４以下にする酸性水処理工程を設けるこ
とを特徴とする膜の殺菌方法。」、「上記に記載の膜の
殺菌方法を用いることを特徴とする造水方法」、「膜分
離装置と、膜分離装置へ供給する供給水に酸性水を供給
する手段とを有していることを特徴とする水処理装
置。」からなるものである。 ─────────────────────────────────────────────────────
The object of the present invention is achieved by the following constitution. That is, the present invention provides a method for sterilizing a membrane, comprising: providing an acidic water treatment step of adjusting the pH of supply water supplied to the membrane separation apparatus to 4 or less when separating and purifying water using the membrane separation apparatus. '', `` A method for producing fresh water characterized by using the method for sterilizing a membrane described above '', `` having a membrane separation device, and a means for supplying acidic water to supply water supplied to the membrane separation device. A water treatment apparatus characterized by the above-mentioned. " ────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成１１年１２月２２日（１９９９．１２．
２２）[Submission date] December 22, 1999 (1999.12.
22)
【手続補正１】[Procedure amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】特許請求の範囲[Correction target item name] Claims
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【特許請求の範囲】[Claims]
【手続補正２】[Procedure amendment 2]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】０００４[Correction target item name] 0004
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【０００４】[0004]
【課題を解決するための手段】本発明の目的は下記の構
成により達成される。即ち本発明は、「膜分離装置を用
いて水を分離精製しながら、膜分離装置へ供給する供給
水のｐＨを４以下にする酸性水処理工程を実施すること
を特徴とする膜の殺菌方法。」、「上記に記載の膜の殺
菌方法を用いることを特徴とする造水方法」、「逆浸透
膜を分離膜とする膜分離装置と、膜分離装置へ供給する
供給水に酸性水を供給する手段とを有していることを特
徴とする水処理装置。」からなるものである。The object of the present invention is achieved by the following constitution. That is, the present invention provides a method for sterilizing a membrane, comprising performing an acidic water treatment step of reducing the pH of supply water supplied to a membrane separation apparatus to 4 or less while separating and purifying water using a membrane separation apparatus. "," A method for producing fresh water characterized by using the method for sterilizing a membrane described above "," Reverse osmosis "
A water treatment apparatus comprising: a membrane separation device using a membrane as a separation membrane; and a means for supplying acidic water to supply water supplied to the membrane separation device. ".
【手続補正３】[Procedure amendment 3]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００１８[Correction target item name] 0018
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【００１８】本発明の膜の殺菌は、被処理水が前処理を
終えて膜モジュールに供給される工程において、間欠的
に実施される。その添加時間、添加頻度は、使用場所、
使用条件などで大きく異なる。例えば、０．５〜２．５
時間の添加を１日ごと、１週間ごと、１ヶ月ごと、と言
った間隔で行うことができる。これらは膜の透過水量の
減少、濃縮液の生菌数や含有有機炭素の増加、膜圧の上
昇などによって変動する。 The sterilization of the membrane of the present invention is carried out intermittently in the process in which the water to be treated is supplied to the membrane module after the pretreatment. The time and frequency of addition depend on the place of use,
It varies greatly depending on conditions of use. For example, 0.5 to 2.5
The addition of time can be done at daily, weekly, monthly, etc. intervals. These fluctuate due to a decrease in the amount of permeated water through the membrane, an increase in the number of viable bacteria in the concentrated solution, an increase in the amount of organic carbon contained, and an increase in the membrane pressure .
【手続補正４】[Procedure amendment 4]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００２８[Correction target item name] 0028
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【００２８】[0028]
【実施例】以下に実施例を挙げて本発明を具体的に説明
するが、本発明はこれらの実施例によりなんら限定され
るものではない。参考 例１ 加圧滅菌（１２０℃、１５分）後硫酸を添加してｐＨを
調整した生理食塩水（食塩濃度０．９％）に、大腸菌
（Escherichia coli K12 IFO 3301）の懸濁液をそれぞ
れ一定量ずつ加え、２０℃で一定時間保持した後に残存
する生菌数を添加時の生菌数で割って生存率を求めた。
この結果、硫酸１０ｐｐｍの添加（ｐＨ４．７）では
２．５時間保持しても生存率は９０％以上であったが、
５０ｐｐｍの添加（ｐＨ３．２）では、０．５時間の保
持で生存率が９０％、１時間で２０％、２．５時間で１
％以下となった。硫酸を１００ｐｐｍ添加すれば、０．
５時間の保持で１％以下の生存率となった。参考 例２ 加圧滅菌（１２０℃、１５分）後硫酸を添加してｐＨを
調整した市販の３．５％人工海水に、実施例１で使用し
た大腸菌、海水の脱塩に使用した逆浸透膜の堆積物懸濁
液、およびその懸濁液から分離した中で最も数の多かっ
た未同定細菌をそれぞれ一定量ずつ加え、２０℃で一定
時間保持した後の生存率を求めて表２の結果を得た。な
お比較のため、硫酸に代えて亜硫酸水素ナトリウムを５
００ｐｐｍ添加した結果も列記した。表１から、ｐＨ
４．０以下に０．５時間以上保持することによって極め
て高い殺菌効果が提供されることが理解できる。EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Reference Example 1 A suspension of Escherichia coli K12 IFO 3301 was placed in a physiological saline solution (salt concentration: 0.9%) adjusted by adding sulfuric acid after autoclaving (120 ° C., 15 minutes). Viability was determined by dividing the number of viable cells remaining after keeping the solution at 20 ° C. for a certain period of time by the number of viable cells at the time of addition.
As a result, with the addition of sulfuric acid 10 ppm (pH 4.7), the survival rate was 90% or more even after holding for 2.5 hours.
With the addition of 50 ppm (pH 3.2), the survival rate was 90% for 0.5 hours, 20% for 1 hour, and 1% for 2.5 hours.
% Or less. If 100 ppm of sulfuric acid is added, 0.1% is added.
The retention of 5 hours resulted in a survival rate of 1% or less. Reference Example 2 Commercially available 3.5% artificial seawater adjusted to pH by adding sulfuric acid after autoclaving (120 ° C., 15 minutes) and reverse osmosis used for desalting Escherichia coli used in Example 1 and seawater A fixed amount of each of the membrane sediment suspension and the largest number of unidentified bacteria separated from the suspension was added, and the survival rate after holding at 20 ° C. for a fixed time was determined. The result was obtained. For comparison, 5% sodium bisulfite was used instead of sulfuric acid.
The results of adding 00 ppm are also listed. From Table 1, the pH
It can be understood that an extremely high bactericidal effect is provided by keeping the temperature at 4.0 or less for 0.5 hour or more.
【手続補正５】[Procedure amendment 5]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００３０[Correction target item name] 0030
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【００３０】実施例１ 海水を供給水として用い、ポリアミドからなる逆浸透膜
を用いた膜分離装置２機を同時並行で運転し、淡水への
逆浸透濾過を行った。このうち１機は、前処理後の海水
に硫酸を加えてｐＨを３．５〜４．０に調整した供給水
を、１日に３０分通水した。１ヶ月間連続運転を行った
結果、硫酸を加えなかったほうの装置は膜圧の上昇が見
られたが、硫酸を加えたほうは変化がなかった。また通
常運転時に濾過濃縮水の生菌数を測定したところ、硫酸
処理を行った後の装置では、硫酸処理をしていない装置
と比較して、１／１００以下に減少していた。 実施例２ 寒天塗抹法で測定した生菌数が１ｍｌあたり２００個で
ある海水を供給水として用い、ポリアミドからなる逆浸
透膜を用いた膜分離装置を運転して逆浸透分離を行っ
た。前処理工程において供給海水に塩素の残存濃度が１
ｐｐｍとなるよう塩素系殺菌剤を連続添加し、逆浸透膜
モジュールの手前で亜硫酸水素ナトリウムを添加した。
亜硫酸水素ナトリウムの添加濃度は、逆浸透膜モジュー
ルから排出されるブライン中の残存濃度が１ｐｐｍ以上
になるように調節した。亜硫酸水素ナトリウムの消費量
は当初５ｐｐｍであったのが、１０日間連続運転を行っ
た結果、３５ｐｐｍまで上昇した。この間膜差圧は約
０．０１ＭＰａ上昇した。硫酸を加えてｐＨを３〜４に
調整した供給水を、１日３０分通水したところ、亜硫酸
水素ナトリウムの消費量は８ｐｐｍまで減少した。その
時の膜差圧は０．０１ＭＰａ上昇した状態を維持してい
た。 実施例３ 寒天塗抹法で測定した生菌数が１ｍｌあたり２０万個で
ある海水を供給水として用い、ポリアミドからなる逆浸
透膜を用いた膜分離装置を運転して逆浸透分離を行っ
た。前処理工程では塩素系殺菌剤を１ｐｐｍ、脱塩素剤
として亜硫酸水素ナトリウムを６ｐｐｍ、それぞれ連続
注入し、膜分離工程では亜硫酸水素ナトリウム５００ｐ
ｐｍを１週間に１時間添加した。約１ヶ月経過後膜差圧
は約０．０２ＭＰａ上昇した。同じ装置を用いて、前処
理工程では、塩素系殺菌剤１ｐｐｍを１日１時間、亜硫
酸水素ナトリウム６ｐｐｍを１日３時間それぞれ間欠的
に添加し、膜分離工程では硫酸を加えてｐＨ４に調整し
た供給水を１日１時間通水した。約１ヶ月経過しても膜
差圧はほとんど変化しなかった。 実施例４ 前処理工程までは実施例３の後半と同じ条件で、膜分離
工程での殺菌を行わないで５０日間運転した結果、膜差
圧が０．０３ＭＰａ上昇した。この時点から膜分離工程
で硫酸を加えてｐＨ３に調整した供給水を１日１時間通
水した結果、８日後には膜差圧が０．０１５ＭＰａ低下
した。さらに膜分離工程での殺菌を中止して２０日間運
転した結果、膜差圧が０．０２ＭＰａ上昇した。この時
点から膜分離工程で硫酸を加えてｐＨ４に調整した供給
水を１日１時間通水した結果、１２日後には膜差圧が
０．０１２ＭＰａ低下した。Example 1 Using seawater as feed water, two membrane separators using a reverse osmosis membrane made of polyamide were operated in parallel to perform reverse osmosis filtration to fresh water. Among these, one machine supplied sulfuric acid to seawater after pretreatment to adjust the pH to 3.5 to 4.0, and supplied water for 30 minutes a day. As a result of continuous operation for one month, the membrane pressure of the apparatus without addition of sulfuric acid was increased, but the apparatus with addition of sulfuric acid did not change. In addition, when the viable cell count of the filtered concentrated water was measured during normal operation, the device after the sulfuric acid treatment was reduced to 1/100 or less of the device without the sulfuric acid treatment. Example 2 Reverse osmosis separation was carried out by using a seawater having a viable cell count of 200 per 1 ml as measured by an agar smear method as a feed water and operating a membrane separator using a reverse osmosis membrane made of polyamide. In the pretreatment process, the residual concentration of chlorine in the supplied seawater is 1
A chlorine-based germicide was continuously added so as to be ppm, and sodium bisulfite was added just before the reverse osmosis membrane module.
The concentration of sodium bisulfite added was adjusted so that the residual concentration in the brine discharged from the reverse osmosis membrane module was 1 ppm or more. The consumption amount of sodium bisulfite was 5 ppm at the beginning, but increased to 35 ppm as a result of continuous operation for 10 days. The transmembrane pressure increased by about 0.01 MPa. When feed water whose pH was adjusted to 3 to 4 by adding sulfuric acid was passed for 30 minutes a day, the consumption of sodium bisulfite was reduced to 8 ppm. The transmembrane pressure at that time was maintained in a state of increasing by 0.01 MPa. Example 3 Reverse osmosis separation was performed by using a seawater having a viable cell count of 200,000 per 1 ml as measured by an agar smear method as a feed water and operating a membrane separation apparatus using a reverse osmosis membrane made of polyamide. In the pretreatment step, 1 ppm of a chlorine-based disinfectant and 6 ppm of sodium bisulfite as a dechlorinating agent were continuously injected, and in the membrane separation step, 500 p of sodium bisulfite.
pm was added for one hour per week. After about one month, the transmembrane pressure increased by about 0.02 MPa. Using the same apparatus, in the pretreatment step, 1 ppm of a chlorine-based disinfectant was added intermittently for 1 hour per day, and 6 ppm of sodium bisulfite was added intermittently for 3 hours per day. In the membrane separation step, sulfuric acid was added to adjust the pH to 4. Feed water was passed for one hour a day. Even after about one month, the transmembrane pressure hardly changed. Example 4 As a result of operating for 50 days under the same conditions as in the latter half of Example 3 up to the pretreatment step without performing sterilization in the membrane separation step, the membrane differential pressure increased by 0.03 MPa. From this point, feed water adjusted to pH 3 by adding sulfuric acid in the membrane separation step was passed for 1 hour per day. As a result, the membrane differential pressure decreased 0.015 MPa after 8 days. Furthermore, as a result of stopping the sterilization in the membrane separation step and operating for 20 days, the membrane differential pressure increased by 0.02 MPa. From this point, feed water adjusted to pH 4 by adding sulfuric acid in the membrane separation step was passed for one hour a day, and as a result, the membrane differential pressure decreased by 0.012 MPa after 12 days.
───────────────────────────────────────────────────── フロントページの続き Ｆターム(参考） 4D006 GA03 HA21 HA41 HA61 JA55C JA63C KA02 KA03 KA14 KA52 KA54 KA55 KA63 KB15 KB30 KC27 KD02 KD08 KD11 KD23 KE02P KE06P KE07Q KE11R KE15R KE16Q KE28R KE30Q MA01 MA03 MA06 MA25 MA31 MA33 MC18 MC32 MC48 MC52 MC54X MC58 PA02 PB03 PB24 PB70 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 4D006 GA03 HA21 HA41 HA61 JA55C JA63C KA02 KA03 KA14 KA52 KA54 KA55 KA63 KB15 KB30 KC27 KD02 KD08 KD11 KD23 KE02P KE06P KE07Q KE11R KE15R KE16Q33 MA28 MC52 MC54X MC58 PA02 PB03 PB24 PB70
Claims (12)
製を行なうに際して、一部の時間において、膜分離装置
への供給液のｐＨを４以下とする酸性水処理工程を有す
ることを特徴とする膜の殺菌方法。1. A method for separating and purifying water using a membrane separation apparatus having a membrane, comprising an acidic water treatment step of setting a pH of a liquid supplied to the membrane separation apparatus to 4 or less for a part of time. Characteristic method of sterilizing membrane.
間の連続供給であることを特徴とする請求項１記載の膜
の殺菌方法。2. The method for sterilizing a membrane according to claim 1, wherein the acidic water treatment step is a continuous supply for 0.5 to 2.5 hours.
あることを特徴とする請求項１または２記載の膜の殺菌
方法。3. The method for sterilizing a membrane according to claim 1, wherein the frequency of the acidic water treatment is once a day to once a month.
項１〜３いずれかに記載の膜の殺菌方法。4. The method according to claim 1, wherein the membrane is a reverse osmosis membrane.
る請求項１〜４いずれかに記載の膜の殺菌方法。5. The method for sterilizing a membrane according to claim 1, wherein the liquid supplied to the membrane is seawater.
ことを特徴とする請求項１〜５いずれかに記載の膜の殺
菌方法。6. The method for sterilizing a membrane according to claim 1, wherein sulfuric acid is added to the supply liquid in an amount of 120 ppm or more.
製する方法であって、請求項１〜６いずれかの膜の殺菌
方法の工程を含むことを有することを特徴とする水の分
離精製方法。7. A method for separating and purifying water using a membrane separation apparatus having a membrane, comprising the step of sterilizing a membrane according to any one of claims 1 to 6. Separation and purification method.
ることを特徴とする請求項７記載の水の分離精製方法。8. The method for separating and purifying water according to claim 7, wherein the supply water for separating and purifying water is seawater.
ており、前処理装置に対して間欠的に塩素を供給するこ
とを特徴とする請求項７または８記載の水の分離精製方
法。9. The method for separating and purifying water according to claim 7, wherein a pretreatment device is provided at a stage preceding the membrane separation device, and the chlorine is supplied intermittently to the pretreatment device. .
て、前記塩素を供給する時間に合わせて還元剤を添加す
ることを特徴とする請求項９記載の水の分離方法。10. The method for separating water according to claim 9, wherein a reducing agent is added between the pretreatment device and the membrane separation device in accordance with the time for supplying the chlorine.
に酸性水を供給する手段を有することを特徴とする水処
理装置。11. A water treatment apparatus comprising: a membrane separation device; and means for supplying acidic water to a liquid supplied to the membrane separation device.
処理装置。12. The water treatment apparatus according to claim 11, wherein the acidic water is sulfuric acid.
Priority Applications (14)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11104985A JP3087750B2 (en) | 1998-07-21 | 1999-04-13 | Sterilization method of membrane |
| ES99929884T ES2300149T3 (en) | 1998-07-21 | 1999-07-16 | PROCEDURE FOR THE INHIBITION OF THE DEVELOPMENT OF BACTERIA IN THE NEIGHBORHOOD OF A MEMBRANE OF SEPARATION AND STERILIZATION TECHNIQUE OF THIS. |
| CN200310113118.7A CN1261194C (en) | 1998-07-21 | 1999-07-16 | Method of bacteriostasis or disinfection for permselective membrane |
| US09/508,886 US6468430B1 (en) | 1998-07-21 | 1999-07-16 | Method for inhibiting growth of bacteria or sterilizing around separating membrane |
| AU46538/99A AU4653899A (en) | 1998-07-21 | 1999-07-16 | Method for inhibiting growth of bacteria or sterilizing around separating membrane |
| CNB998011517A CN1140324C (en) | 1998-07-21 | 1999-07-16 | Method for inhibiting growth of bacteria or sterilizing around separating membrane |
| ES07023854T ES2429098T3 (en) | 1998-07-21 | 1999-07-16 | Bacteriostasis or disinfection procedure for selective permeable membranes |
| EP99929884A EP1031372B1 (en) | 1998-07-21 | 1999-07-16 | Method for inhibiting growth of bacteria or sterilizing around separating membrane |
| PCT/JP1999/003860 WO2000004986A1 (en) | 1998-07-21 | 1999-07-16 | Method for inhibiting growth of bacteria or sterilizing around separating membrane |
| EP07023854.8A EP1900417B1 (en) | 1998-07-21 | 1999-07-16 | Method of bacteriostasis or disinfection for permselective membrane |
| SA99200699A SA99200699B1 (en) | 1998-07-21 | 1999-10-24 | A method for inhibition or disinfection of selective permeable membrane bacteriostasis |
| HK01103509A HK1032761A1 (en) | 1998-07-21 | 2001-05-22 | Method for inhibiting growth of bacteria or sterilizing around separating membrane. |
| US10/230,129 US6743363B2 (en) | 1998-07-21 | 2002-08-29 | Method of bacteriostasis or disinfection for permselective membrane |
| HK04108058A HK1065302A1 (en) | 1998-07-21 | 2004-10-18 | Disinfection method for separation membranes, pre-treatment apparatus therefor and method for purifying water |
Applications Claiming Priority (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10-204873 | 1998-07-21 | ||
| JP20487398 | 1998-07-21 | ||
| JP29047898 | 1998-10-13 | ||
| JP10-290478 | 1998-12-24 | ||
| JP10-367937 | 1998-12-24 | ||
| JP36793798 | 1998-12-24 | ||
| JP11104985A JP3087750B2 (en) | 1998-07-21 | 1999-04-13 | Sterilization method of membrane |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23963999A Division JP2000237546A (en) | 1998-07-21 | 1999-08-26 | Production of fresh water |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000237555A true JP2000237555A (en) | 2000-09-05 |
| JP3087750B2 JP3087750B2 (en) | 2000-09-11 |
Family
ID=27469273
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11104985A Expired - Lifetime JP3087750B2 (en) | 1998-07-21 | 1999-04-13 | Sterilization method of membrane |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3087750B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002320968A (en) * | 2001-04-27 | 2002-11-05 | Japan Organo Co Ltd | Membrane separation method |
| JP2006015236A (en) * | 2004-07-01 | 2006-01-19 | Toray Ind Inc | Apparatus and method for preparing regenerated water |
| US7090780B2 (en) | 2001-04-05 | 2006-08-15 | Toray Industries, Inc. | Bactericide for use in water treatment, method for water treatment and apparatus for water treatment |
| JP2008036522A (en) * | 2006-08-04 | 2008-02-21 | Kurita Water Ind Ltd | Method for treating reverse osmosis membrane |
| JP2011088151A (en) * | 2011-02-09 | 2011-05-06 | Toray Ind Inc | Apparatus and method for preparing regenerated water |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110226695A1 (en) | 2006-05-09 | 2011-09-22 | Toray Industries, Inc. | Method for producing fresh water |
-
1999
- 1999-04-13 JP JP11104985A patent/JP3087750B2/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7090780B2 (en) | 2001-04-05 | 2006-08-15 | Toray Industries, Inc. | Bactericide for use in water treatment, method for water treatment and apparatus for water treatment |
| JP2002320968A (en) * | 2001-04-27 | 2002-11-05 | Japan Organo Co Ltd | Membrane separation method |
| JP2006015236A (en) * | 2004-07-01 | 2006-01-19 | Toray Ind Inc | Apparatus and method for preparing regenerated water |
| JP2008036522A (en) * | 2006-08-04 | 2008-02-21 | Kurita Water Ind Ltd | Method for treating reverse osmosis membrane |
| JP2011088151A (en) * | 2011-02-09 | 2011-05-06 | Toray Ind Inc | Apparatus and method for preparing regenerated water |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3087750B2 (en) | 2000-09-11 |
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