JP2001300530A - Method of purifying natural water with membrane - Google Patents
Method of purifying natural water with membraneInfo
- Publication number
- JP2001300530A JP2001300530A JP2001103072A JP2001103072A JP2001300530A JP 2001300530 A JP2001300530 A JP 2001300530A JP 2001103072 A JP2001103072 A JP 2001103072A JP 2001103072 A JP2001103072 A JP 2001103072A JP 2001300530 A JP2001300530 A JP 2001300530A
- Authority
- JP
- Japan
- Prior art keywords
- backwashing
- water
- hollow fiber
- membrane
- filtration
- 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.)
- Pending
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、中空糸型の濾過膜
モジュールを用いた天然水の膜浄化方法に関し、更に詳
しくは水浄化システムにおける中空糸型の濾過膜モジュ
ールの処理能力を回復させながら行う天然水の膜浄化方
法に関し、特に逆洗洗浄の操作性、効率がよく、しかも
中空糸型の濾過膜モジュールへの負荷が少ない膜洗浄を
伴う天然水の膜浄化方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying natural water using a hollow fiber type filtration membrane module, and more particularly to a method for recovering the processing capacity of a hollow fiber type filtration membrane module in a water purification system. More particularly, the present invention relates to a method for purifying natural water with high operability and efficiency in backwashing, and with a small load on a hollow fiber type filtration membrane module.
【０００２】[0002]
【従来の技術】最近、膜分離技術を適用する水浄化シス
テムは、従来の凝集−沈澱−砂濾過−塩素滅菌工程を経
る方法に代わる新たな技術として注目されている。例え
ば、分離膜を用いた水浄化システムとしてはクロスフロ
ー濾過が広く試行されている。ここにクロスフロー濾過
とは、分離膜の一方の膜面（原水供給側分離膜面）に原
水を供給し、分離膜を透過した透過水を分離膜の他方の
膜面（透過水側分離膜面）から回収する際、原水供給側
分離膜面に平行に原水を流して濾過を行うことにより、
分離膜表面に付着した原水に含まれていた濁質物質をそ
の膜表面からはぎ取る効果を有する濾過方法をいう。し
かし、クロスフロー濾過によっても、濾過時間の経過に
よって原水に含まれる濁質物質が分離膜表面に積層し
て、分離膜の目詰まりを生ずる。2. Description of the Related Art Recently, a water purification system to which a membrane separation technique is applied has been attracting attention as a new technique which replaces a conventional method involving a coagulation-precipitation-sand filtration-chlorine sterilization process. For example, as a water purification system using a separation membrane, cross-flow filtration has been widely tried. Here, the cross-flow filtration means that raw water is supplied to one membrane surface of the separation membrane (raw water supply side separation membrane surface), and the permeated water that has passed through the separation membrane is separated into the other membrane surface of the separation membrane (permeated water side separation membrane). Surface), the raw water flows in parallel to the raw water supply-side separation membrane surface and is filtered.
It refers to a filtration method that has an effect of stripping turbid substances contained in raw water attached to the surface of a separation membrane from the surface of the membrane. However, even in the cross-flow filtration, the turbid substances contained in the raw water are stacked on the surface of the separation membrane with the passage of the filtration time, and the separation membrane is clogged.
【０００３】この目詰まりは水浄化システムの運転中断
の原因となるため、この目詰まりを解消あるいは予防す
るために、一般に逆流洗浄（以下、「逆洗」と称す。）
が行われている。分離膜の長期使用を可能とするため、
原水濁度、透過水量、透過水圧等の各種変化量等に基づ
いて逆洗頻度、逆洗時間等を変化させる方法等が提案さ
れている。例えばクロスフロー濾過における逆洗として
は、原水濁度に依存した定期的な逆洗が水道協会雑誌
（Ｖｏｌ．６１，Ｎｏ．１１，１９−２６，１９９２）
に記載され、特開平４−２４７２２６号公報には、水質
と濾過量の変動により濾過量低下傾向時に膜の逆洗条件
を変更させる方法が開示され、特開平５−３１７６６０
号公報には、原水濁度の変動に応じて逆洗の頻度を調節
し、分離膜を閉鎖させる危険を排除し、かつ用水の回収
率を高めることができる方法が開示されている。[0003] Since the clogging causes an interruption of the operation of the water purification system, in order to eliminate or prevent the clogging, backwashing is generally performed (hereinafter referred to as "backwashing").
Has been done. To enable long-term use of the separation membrane,
A method has been proposed in which the frequency of backwashing, the time of backwashing, and the like are changed based on various changes in raw water turbidity, permeated water amount, permeated water pressure, and the like. For example, as backwashing in cross-flow filtration, periodic backwashing depending on raw water turbidity is performed by a magazine of the Japan Water Works Association (Vol. 61, No. 11, 19-26, 1992).
Japanese Patent Application Laid-Open No. 4-247226 discloses a method for changing the backwashing conditions of a membrane when the filtration amount tends to decrease due to fluctuations in water quality and filtration amount.
The publication discloses a method in which the frequency of backwashing is adjusted according to the fluctuation of raw water turbidity, the danger of closing the separation membrane is eliminated, and the recovery rate of water can be increased.
【０００４】[0004]
【発明が解決しようとする課題】しかしこれらの方法に
よれば、原水側分離膜面に濁質物質が付着した場合に
は、その目詰まりによって原水供給側の原水圧が上昇す
るため、その上昇した圧力の数倍の圧力を逆洗圧として
用い、濁質物質の剥離を実施しようとするものである。
従って、分離膜には常に高圧が負荷されることとなり、
分離膜の耐用年数が短縮される恐れがある。しかも、高
圧負荷は分離膜のみならず、使用されるポンプにも及
ぶ。従って、逆洗効率の向上、ならびに高価な分離膜モ
ジュールの使用条件を緩和し、かつ、各種水浄化システ
ムに容易に対応できる逆洗方法の開発が熱望されてい
る。However, according to these methods, when a turbid substance adheres to the raw water side separation membrane surface, the raw water pressure on the raw water supply side rises due to clogging, so that the rising A pressure several times higher than the above pressure is used as the backwash pressure to remove the suspended substance.
Therefore, a high pressure is always applied to the separation membrane,
The service life of the separation membrane may be shortened. Moreover, the high pressure load extends not only to the separation membrane but also to the pump used. Therefore, there is a strong demand for improvement of the backwashing efficiency, development of a backwashing method capable of relaxing the use conditions of the expensive separation membrane module and easily coping with various water purification systems.
【０００５】[0005]
【課題を解決するための手段】本発明者は上記現状に鑑
み、水浄化システムならびに逆洗について詳細に検討し
た結果、殺菌剤を含む逆洗水により逆洗する操作と、そ
の直後に濾過処理を休止する操作を含む逆洗過程を設け
る天然水の膜浄化方法を見いだし、本発明を完成するに
至った。In view of the above situation, the present inventor has studied the water purification system and backwashing in detail. As a result, an operation of backwashing with backwash water containing a bactericide, and a filtration treatment immediately thereafter. The present inventors have found a method for purifying natural water by membrane in which a backwashing process including an operation of stopping the process is performed, and have completed the present invention.
【０００６】すなわち本発明は、中空糸型の限外または
精密濾過膜モジュールを用いて天然水を濾過する天然水
の膜浄化方法において、中空糸型の濾過膜モジュールを
殺菌剤を含む逆洗水により逆洗する操作と、その直後に
濾過処理を休止する操作からなる逆洗過程を設けること
を特徴とする天然水の膜浄化方法を提供するものであ
る。That is, the present invention relates to a method for purifying natural water by filtering natural water using a hollow fiber type ultra or microfiltration membrane module. The present invention provides a method for purifying natural water membranes, characterized by providing a backwashing process consisting of an operation of backwashing by a step (1) and an operation of immediately stopping the filtration treatment.
【０００７】[0007]
【作用】本発明の参考とする発明（参考発明）の態様
は、中空糸型の濾過膜モジュールに原水を供給するため
の原水供給ポンプを所定時間停止することによって濾過
処理を休止させる過程を有する。この過程を「濾過処理
の休止過程」という。当該過程により、濾過処理により
加圧され、圧密化していた中空糸型の濾過膜モジュール
の「原水供給側分離膜面の目詰まり物質」は、一時的に
放圧され、濾過膜面との付着力が緩和されるため、膜面
から濾過膜面との付着力が緩和されるため、膜面から剥
離し易い状態になる。なお、前記の「所定」とは、膜モ
ジュールの処理能力の状況に応じて本参考発明を実施す
る際に、実施者において適宜定められることを意味する
（以下における「所定」も同様である）。従って、当該
過程を逆洗の直前に設けることにより、逆洗効率が向上
する。なお、逆洗水に殺菌剤を含ませて、中空糸型の濾
過膜モジュールの殺菌ならびに濾過膜表面に付着した微
生物や有機物を分解させることも可能である。本発明の
態様は、濾過処理後に殺菌剤を含む逆洗水による逆洗操
作、逆洗および濾過処理の休止操作、逆洗操作の
連続した三操作からなる「休止付き逆洗過程」のおよ
びに相当する。この場合、逆洗および濾過処理の休
止操作で、化学的に殺菌剤による中空糸型の濾過膜の
洗浄を十分に行ない、かつ、膜への高圧負荷を緩和させ
る。以下、詳細に本発明を説明する。According to an embodiment of the invention (reference invention) to which the present invention is applied, a filtration process is stopped by stopping a raw water supply pump for supplying raw water to a hollow fiber type filtration membrane module for a predetermined time. . This process is referred to as a “stop process of the filtration process”. In this process, the "clogging substance on the raw water supply side separation membrane surface" of the hollow fiber type filtration membrane module which has been pressurized and consolidated by the filtration treatment is temporarily released and attached to the filtration membrane surface. Since the adhesive force is eased, the adhesive force from the membrane surface to the filtration membrane surface is eased, so that the membrane surface is easily separated. The above “predetermined” means that it is appropriately determined by the practitioner when implementing the present invention according to the state of the processing capability of the membrane module (the same applies to “predetermined” below). . Therefore, by providing the process immediately before the backwash, the backwash efficiency is improved. In addition, it is also possible to add a bactericide to the backwash water to sterilize the hollow fiber type filtration membrane module and decompose microorganisms and organic substances attached to the filtration membrane surface. The embodiment of the present invention includes a backwashing operation with backwashing water containing a bactericide after the filtration treatment, a backwashing and filtration treatment suspension operation, and a backwashing process with a suspension consisting of three consecutive backwashing operations. Equivalent to. In this case, the hollow fiber type filtration membrane is sufficiently washed with a bactericide and the high-pressure load on the membrane is reduced by suspending the backwashing and filtration treatments. Hereinafter, the present invention will be described in detail.
【０００８】中空糸型の濾過膜モジュールを用いた水浄
化システムでは、濾過処理による透過水生成と、中空糸
型の濾過膜の目詰まりを防ぐための逆洗とを交互に実施
し、これを通常運転とするのが一般的である。ここに逆
洗は、原水供給側分離膜面に付着した濁質物質の除去の
ため、圧力制御もしくは定時間間隔で行われる。すなわ
ち、中空糸型の濾過膜に対し透過水生成と逆方向に逆洗
水を流入するものである。なお、洗浄後の洗浄水は洗浄
水排出経路より排出される。水浄化システムが内圧式ク
ロスフロー濾過の場合には、中空糸型の濾過膜の内面が
原水供給分離膜面となり、ここに付着した濁質物質は、
中空糸型の濾過膜の外面すなわち透過水側分離膜面から
逆洗水を注入させることにより剥離・除去される。In a water purification system using a hollow fiber type filtration membrane module, generation of permeated water by filtration and backwashing for preventing clogging of the hollow fiber type filtration membrane are performed alternately. It is common to operate normally. Here, the backwashing is performed at a pressure control or at regular time intervals in order to remove suspended substances adhered to the separation membrane surface on the raw water supply side. That is, the backwash water flows into the hollow fiber type filtration membrane in the opposite direction to the generation of the permeated water. The cleaning water after the cleaning is discharged from the cleaning water discharge path. When the water purification system is an internal pressure type cross-flow filtration, the inner surface of the hollow fiber type filtration membrane becomes the raw water supply / separation membrane surface, and the turbid substance attached here is:
It is separated and removed by injecting backwash water from the outer surface of the hollow fiber type filtration membrane, that is, the permeated water side separation membrane surface.
【０００９】参考発明による膜浄化方法は、中空糸型の
濾過膜モジュールを用いた水浄化システムの通常運転に
おける「逆洗」の直前に、前記した「濾過処理の休止過
程」を設けるものである。当該過程により加圧されて圧
密化していた原水供給側分離膜面の目詰まりが一時的に
放圧され、膜面から剥離し易い状態となり、このため透
過水の流れとは逆方向に行われる逆洗は、その逆洗効率
が向上する。従って、当該過程を逆洗の直前に設けるこ
とにより、効果的な逆洗が可能となる。なお、濾過処理
の休止過程は、３０秒から１５分であることが好まし
く、特には２〜１０分の範囲であることが好ましい。こ
の範囲で目詰まり物質の圧力緩和が起こり、逆洗効率が
向上し、かつ、濾過処理の遅延による処理量の著しい低
下も生じないからである。さらに、濾過処理の休止過程
は毎逆洗時に設けてもよいし、濾過性能が低下した場合
にのみ設けてもよい。In the membrane purification method according to the reference invention, the above-mentioned "stopping process of filtration treatment" is provided immediately before "backwashing" in normal operation of a water purification system using a hollow fiber type filtration membrane module. . The clogging of the raw water supply side separation membrane surface, which was pressurized and compacted by the process, is temporarily released, and the membrane is easily peeled off from the membrane surface, so that the flow is performed in the opposite direction to the flow of the permeated water. Backwashing improves the backwashing efficiency. Therefore, by providing this process immediately before backwashing, effective backwashing becomes possible. The suspension process of the filtration treatment is preferably for 30 seconds to 15 minutes, and particularly preferably for 2 to 10 minutes. This is because the pressure of the clogging substance is relaxed in this range, the backwashing efficiency is improved, and the processing amount is not significantly reduced due to the delay of the filtration processing. Furthermore, the pause process of the filtration treatment may be provided at each backwash, or may be provided only when the filtration performance is reduced.
【００１０】本発明の態様は、中空糸型の濾過膜モジュ
ールを用いた水浄化システムにおける天然水の膜浄化方
法として、「休止付き逆洗過程」を設けるものである。
この過程は、水浄化システムの通常濾過運転稼働中に、
数十時間に１回設けてもよいし、濾過膜の性能が低下し
た場合にのみ設けてもよい。なお、濾過膜の性能の低下
は、フラックスの低下や濾過圧の上昇の程度などより把
握される指標を目安とする。この過程は、まず濾過処理
後に殺菌剤を含む逆洗水による逆洗操作を実施し、そ
の後逆洗および濾過処理の休止操作を設けるものであ
る。このことにより中空糸型の濾過膜は殺菌剤が満たさ
れた状態となり、薬剤による濁質物質の分解が進み、中
空糸型の濾過膜への圧力負荷が緩和されるとともに化学
的分解による濁質物質の除去が可能となる。次いで、逆
洗操作により濁質物質の系外への除去を行い、その後
濾過運転を継続する。なお、逆洗および濾過処理の休止
操作は、１〜１０時間であることが好ましく、特には
２〜５時間の範囲が好ましい。この範囲で濁質物質の分
解が十分なされ、十分な圧力負荷の緩和がなされるから
である。なお、水浄化システムの通常運転に、前記した
「濾過処理の休止過程」を設けた濾過運転を行い、さら
に、数十時間に一回の頻度で当該「休止付き逆洗過程」
を設けた濾過運転を行ってもよい。[0010] An embodiment of the present invention is to provide a "backwashing process with pause" as a method for purifying natural water in a water purification system using a hollow fiber type filtration membrane module.
This process occurs during the normal filtration operation of the water purification system.
It may be provided once every several tens of hours, or may be provided only when the performance of the filtration membrane is reduced. It should be noted that a decrease in the performance of the filtration membrane is taken as an index based on the degree of decrease in the flux or increase in the filtration pressure. In this process, first, after the filtration treatment, a backwash operation with backwash water containing a bactericide is performed, and thereafter, the backwash and the filtration treatment are stopped. As a result, the hollow fiber type filtration membrane is filled with a bactericide, the decomposition of the turbid substance by the chemical proceeds, the pressure load on the hollow fiber type filtration membrane is reduced, and the turbidity due to the chemical decomposition is reduced. The substance can be removed. Next, the suspended substance is removed from the system by a backwashing operation, and then the filtration operation is continued. The operation of stopping the backwashing and the filtration is preferably 1 to 10 hours, particularly preferably 2 to 5 hours. This is because the suspended substance is sufficiently decomposed in this range, and the pressure load is sufficiently alleviated. In addition, in the normal operation of the water purification system, a filtration operation provided with the above-mentioned "stop process of filtration process" is performed, and the "backwash process with stop" is performed once every several tens of hours.
May be performed.
【００１１】本発明及び参考発明において、逆洗には、
濾過膜モジュールからの透過水または別途供給される清
浄水を用いることができる。また、別途供給される清浄
水として前記濾過膜モジュールからの透過水に殺菌剤を
添加したものを用いてもよい。殺菌剤としては、次亜塩
素酸ナトリウム、塩素、過酸化水素およびオゾンなどの
酸化性殺菌剤、クエン酸およびシュウ酸などの有機酸、
塩酸および硝酸などの無機酸、水酸化ナトリウムなどの
アルカリおよびカチオン系、アニオン系、ノニオン系お
よび両性界面活性剤等を使用することができる。中でも
有機性の目詰まり物質を効果的に酸化分解できる次亜塩
素酸ナトリウムが適する。In the present invention and the reference invention, the backwash includes
Permeated water from the filtration membrane module or separately supplied clean water can be used. Further, as the separately supplied clean water, a water obtained by adding a germicide to permeated water from the filtration membrane module may be used. Disinfectants include oxidizing disinfectants such as sodium hypochlorite, chlorine, hydrogen peroxide and ozone, organic acids such as citric acid and oxalic acid,
Inorganic acids such as hydrochloric acid and nitric acid, alkalis such as sodium hydroxide, and cationic, anionic, nonionic and amphoteric surfactants can be used. Among them, sodium hypochlorite, which can effectively oxidize and decompose organic clogging substances, is suitable.
【００１２】本発明および参考発明は、中空糸型の濾過
膜モジュールを用いた水浄化システムを対象とし、中空
糸型限外または精密濾過膜モジュールを用いることがで
きる。これら中空糸型の濾過膜モジュールの材質として
は、親水性高分子材料である酢酸セルロース、ポリアク
リロニトリル重合体、ポリビニルアルコール等を用いる
ことが可能であり、特には酢酸セルロースが逆洗効果が
顕著に現れるために好ましい。The present invention and the reference invention are directed to a water purification system using a hollow fiber type filtration membrane module, and a hollow fiber type ultra or microfiltration membrane module can be used. As a material of these hollow fiber type filtration membrane modules, it is possible to use a hydrophilic polymer material such as cellulose acetate, polyacrylonitrile polymer, polyvinyl alcohol, and the like. Preferred to appear.
【００１３】浄化用に供給される原水としては、地下
水、雨水、河川水および湖沼水等の天然水を用いること
ができる。As raw water supplied for purification, natural water such as groundwater, rainwater, river water and lake water can be used.
【００１４】以下に中空糸型の濾過膜モジュールを用い
た内圧式クロスフロー濾過による水浄化システムにおい
て、本発明および参考発明の天然水の膜浄化方法につい
て、図面を参照して説明する。The method for purifying natural water according to the present invention and a reference invention in a water purifying system by internal pressure type cross flow filtration using a hollow fiber type filtration membrane module will be described below with reference to the drawings.
【００１５】まず、本発明の「濾過処理の休止過程」を
設けた天然水の膜浄化方法について説明する。水浄化シ
ステムは、透過水生成と中空糸型の濾過膜モジュールの
目詰まりを防ぐための逆洗とを交互に実施している。こ
こに、透過水生成時と逆洗時におけるポンプ、流路弁の
操作は以下の通りである。透過水生成時においては、透
過水自動弁１３を開、洗浄水排出自動弁１４、逆洗自動
弁１９は閉の状態で原水供給ポンプ１１により原水を中
空糸型の濾過膜モジュールに供給して濾過を行い、生成
した透過水を透過水タンク１７に貯留する。なお、中空
糸型の濾過膜モジュールを透過しない原水は循環経路１
６、原水供給ポンプ１１を経て再び中空糸型の濾過膜モ
ジュール１２に送られる。一方参考発明の態様による逆
洗時には、まず原水ポンプ１１が停止され、中空糸型の
濾過膜モジュール１２への原水の供給が３０秒〜１０分
間停止される。次に、原水供給ポンプ１１を停止させて
原水の供給を停止したまま、中空糸型の濾過膜モジュー
ル１２の原水供給側分離膜面に付着した濁質物質を除去
するために、透過水生成時とは逆方向に中空糸型の濾過
膜モジュール１２に逆洗水を供給する。膜面に付着した
濁質物質を剥離した後、濁質物質を系外へ排出する。中
空糸型の濾過膜モジュール１２の逆洗は、例えば３０〜
６０分に一度程度の頻度で行う。逆洗水に透過水を使用
する場合には、透過水自動弁１３を閉、洗浄水排出自動
弁１４、逆洗自動弁１９を開とすると共に、逆洗水供給
ポンプ１８により透過水タンク１７の一部を透過水生成
時とは逆方向に中空糸型の濾過膜モジュール１２に、例
えば約１分間供給する。これにより中空糸型の濾過膜モ
ジュール１２の原水供給側分離膜面の濁質物質を剥離し
た後、濁質物質を高濃度に含有した逆洗水を逆洗水排出
経路１５を経て逆洗水排出自動弁１４から系外へ排出さ
せる。なお、殺菌剤を貯留する薬剤タンク２１を設け
て、逆洗水に殺菌剤を含ませることも可能である。かか
る場合には、逆洗水供給ポンプ１８の稼働と共に薬剤供
給ポンプ２２を稼働させ、合わせて薬剤自動弁２５を開
とする。First, a membrane purification method of natural water provided with the "pause process of filtration treatment" of the present invention will be described. The water purification system alternately performs generation of permeated water and backwashing to prevent clogging of the hollow fiber type filtration membrane module. Here, the operation of the pump and the flow path valve at the time of generation of permeated water and at the time of backwashing are as follows. At the time of permeate generation, the raw water is supplied to the hollow fiber type filtration membrane module by the raw water supply pump 11 with the automatic permeated water valve 13 opened, the automatic cleaning water discharge valve 14 and the automatic backwash valve 19 closed. Filtration is performed, and the generated permeate is stored in a permeate tank 17. The raw water that does not pass through the hollow fiber type filtration membrane module is
6. It is sent to the hollow fiber type filtration membrane module 12 again through the raw water supply pump 11. On the other hand, at the time of backwashing according to the embodiment of the reference invention, the raw water pump 11 is first stopped, and the supply of raw water to the hollow fiber type filtration membrane module 12 is stopped for 30 seconds to 10 minutes. Next, with the raw water supply pump 11 stopped and the supply of raw water stopped, in order to remove turbid substances attached to the raw water supply side separation membrane surface of the hollow fiber type filtration membrane module 12, The backwash water is supplied to the hollow fiber type filtration membrane module 12 in the opposite direction. After the suspended substance adhered to the membrane surface is peeled off, the suspended substance is discharged out of the system. The backwash of the hollow fiber type filtration membrane module 12 is performed, for example, in 30 to 30 hours.
It is performed about once every 60 minutes. When permeated water is used as the backwash water, the automatic permeated water valve 13 is closed, the automatic flush water discharge valve 14 and the automatic backwash valve 19 are opened, and the permeated water tank 17 is controlled by the backwash water supply pump 18. Is supplied to the hollow fiber type filtration membrane module 12 in a direction opposite to the direction in which the permeated water is generated, for example, for about one minute. As a result, the turbid substance on the raw water supply side separation membrane surface of the hollow fiber type filtration membrane module 12 is peeled off, and then the backwash water containing the turbid substance at a high concentration is passed through the backwash water discharge path 15 to the backwash water. It is discharged from the automatic discharge valve 14 to the outside of the system. In addition, it is also possible to provide a chemical tank 21 for storing a germicide, and to make the backwash water contain a germicide. In such a case, the medicine supply pump 22 is operated together with the operation of the backwash water supply pump 18, and the automatic medicine valve 25 is opened.
【００１６】次に本発明による「休止付き逆洗過程」を
伴う膜洗浄方法について説明する。この膜洗浄方法を伴
う水浄化システムにおいては、透過水生成と中空糸型の
濾過膜モジュールの目詰まりを防ぐための逆洗とを交互
に実施し、この逆洗が上記した濾過処理の休止過程を設
けた膜洗浄方法を実施している場合でもよい。通常の透
過水生成時には、上記と同様にポンプ・弁等が稼働し、
次に休止付き逆洗過程に入ると、殺菌剤を含む逆洗水に
よる逆洗操作、すなわち原水供給ポンプ１１を停止
し、逆洗自動弁１９、薬剤自動弁２５を開とし、逆洗水
供給ポンプ１８ならびに薬剤供給ポンプ２２により殺菌
剤を含有した逆洗水により逆洗を１〜３分行う。その
後、逆洗および濾過処理の休止操作、すなわち原水供
給ポンプ１１は停止したまま、逆洗水供給ポンプ１８な
らびに薬剤供給ポンプ２２を停止し、逆洗自動弁１９、
薬剤自動弁２５を閉とし１〜１０時間、透過水生成なら
びに逆洗を共に停止する期間を設ける。次に、逆洗自動
弁１９を開とし、逆洗水供給ポンプ１８により逆洗操作
を行う。なお逆洗操作においても、薬剤自動弁２５
を開とし薬剤供給ポンプ２２により薬剤を逆洗水に含め
ることも可能である。Next, a description will be given of a method of cleaning a film with a “backwash process with pause” according to the present invention. In the water purification system with this membrane cleaning method, generation of permeated water and backwashing to prevent clogging of the hollow fiber type filtration membrane module are alternately performed, and this backwashing is a process of stopping the above-described filtration process. May be carried out when the membrane cleaning method provided with. During normal permeate generation, pumps and valves operate in the same manner as above,
Next, in the backwashing process with a pause, the backwashing operation using the backwashing water containing the sterilizing agent, that is, the raw water supply pump 11 is stopped, the backwashing automatic valve 19 and the chemical automatic valve 25 are opened, and the backwashing water supply is performed. Backwashing is performed for 1-3 minutes with backwash water containing a bactericide by the pump 18 and the chemical supply pump 22. Thereafter, the backwashing and filtration processes are stopped, that is, while the raw water supply pump 11 is stopped, the backwash water supply pump 18 and the chemical supply pump 22 are stopped, and the backwash automatic valve 19,
The automatic chemical valve 25 is closed and a period is provided for stopping permeated water generation and backwashing for 1 to 10 hours. Next, the backwash automatic valve 19 is opened, and the backwash water supply pump 18 performs a backwash operation. In the backwashing operation, the automatic chemical valve 25 is also used.
Can be opened and the medicine supplied to the backwash water by the medicine supply pump 22.
【００１７】[0017]
【実施例】以下、本発明を実施例によりさらに具体的に
説明する。EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples.
【００１８】（参考例１）中空糸型の濾過膜モジュール
として酢酸セルロース製の限外濾過膜モジュール（分画
分子量１５万、有効膜面積５０ｍ2）を用いて河川水の
内圧式濾過運転を行った。運転は「濾過処理の休止過
程」を設ける方法で行った。すなわち、４５分間の透過
水生成期間の後に、原水供給ポンプを１０分間停止して
濾過処理を休止した。その後、圧力１．７Ｋｇ／ｃｍ2
で透過水を逆洗水として中空糸膜の外壁面側から１分間
圧入して中空糸膜の内壁面の付着物を逆洗した。なお、
逆洗水には透過水に次亜塩素酸ナトリウムを注入し、濃
度５ｍｇ／リットルに調整した水溶液を用いた。上記の
一連の操作を自動弁を用いて周期的に行い、濾過速度の
経日変化を測定した結果、濾過速度は低下することなく
安定した運転が継続した。Reference Example 1 An internal pressure filtration operation of river water was performed using a cellulose acetate ultrafiltration membrane module (fraction molecular weight: 150,000, effective membrane area: 50 m 2 ) as a hollow fiber type filtration membrane module. Was. The operation was performed by a method of providing a "stop process of filtration treatment". That is, after the permeated water generation period of 45 minutes, the raw water supply pump was stopped for 10 minutes to suspend the filtration process. Thereafter, the pressure was 1.7 kg / cm 2.
The permeated water was used as backwashing water for 1 minute from the outer wall surface side of the hollow fiber membrane to press-back it, and the deposits on the inner wall surface of the hollow fiber membrane were backwashed. In addition,
As the backwashing water, an aqueous solution prepared by injecting sodium hypochlorite into permeated water and adjusting the concentration to 5 mg / liter was used. The above series of operations were periodically performed using an automatic valve, and the daily change in the filtration rate was measured. As a result, stable operation was continued without decreasing the filtration rate.
【００１９】（実施例１）参考例１と同じ中空糸型の膜
モジュールを用いて、「休止付き逆洗過程」を設けて内
圧式濾過運転を行った。すなわち、４５分毎に１分間の
逆洗を周期的に行う膜浄化方法において、逆洗操作、
２時間の濾過処理の休止、逆洗操作の連続した三操
作を３０時間に１回設けた。なお、逆洗時には参考例１
と同様に殺菌剤として次亜塩素酸ナトリウムを含む逆洗
水（ＮａＣｌＯ濃度５ｍｇ／リットル）を用いた。この
運転操作では濾過速度は低下しなかった。(Example 1) Using the same hollow fiber type membrane module as in Reference Example 1, an internal pressure filtration operation was performed by providing a "backwashing process with pause". That is, in a membrane purification method in which backwashing is performed periodically for 1 minute every 45 minutes,
Three continuous operations of the filtration treatment for 2 hours and the backwashing operation were provided once every 30 hours. In addition, at the time of backwashing, Reference Example 1
Backwash water (NaClO concentration: 5 mg / liter) containing sodium hypochlorite was used as a bactericide in the same manner as in the above. This operation did not reduce the filtration rate.
【００２０】（参考比較例）参考例１と同じ中空糸型の
膜モジュールを用いる運転操作において、「濾過処理の
休止過程」および「休止付き逆洗過程」を設けることな
く、４５分毎に１分間の逆洗操作のみを行った。参考例
１および実施例１の前後に計３回の参考比較例を実施し
たが、濾過速度はいずれも経時的に減少した。(Reference Comparative Example) In the operation using the same hollow fiber type membrane module as in Reference Example 1, the "filtration treatment pause process" and the "backwashing process with pause" were not provided, and one every 45 minutes. Only a backwashing operation for one minute was performed. A total of three reference comparative examples were performed before and after Reference Example 1 and Example 1, and both filtration rates decreased with time.
【００２１】上述の参考例１、実施例１および参考比較
例の濾過運転結果を一連の実験データとして図２に示
す。The results of the filtration operation of Reference Example 1, Example 1 and Reference Comparative Example are shown in FIG. 2 as a series of experimental data.
【００２２】[0022]
【発明の効果】本発明及び参考発明による膜洗浄方法を
伴う天然水の膜浄化方法を用いることにより、中空糸型
の濾過膜の目詰まり処理は極めて容易な操作により行わ
れ、しかも迅速かつ確実に中空糸型の濾過膜の機能が回
復できる。しかも本発明及び参考発明によれば、中空糸
型の濾過膜に対する圧力負荷が緩和されるため、中空糸
型の濾過膜モジュールの延命を図ることが可能である。
加えて、殺菌剤の併用により、中空糸型の濾過膜モジュ
ールの殺菌のみならず濁質物質を化学的に分解させ、膜
自体へ圧力負荷をより緩和する。さらに、中空糸型の濾
過膜の殺菌剤への浸漬時間が長いため、無駄な殺菌剤を
使用せずに膜洗浄が可能となる。従って、殺菌剤の使用
量を低減することが可能となり、費用のみならず環境へ
与える影響も低減することが可能となる。By using the method for purifying natural water with the membrane cleaning method according to the present invention and the reference invention, clogging of the hollow fiber type filtration membrane can be carried out by an extremely easy operation, and quickly and reliably. In addition, the function of the hollow fiber type filtration membrane can be restored. In addition, according to the present invention and the reference invention, since the pressure load on the hollow fiber type filtration membrane is reduced, the life of the hollow fiber type filtration membrane module can be extended.
In addition, the combined use of a disinfectant not only disinfects the hollow fiber type filtration membrane module but also chemically decomposes turbid substances and further reduces the pressure load on the membrane itself. Further, since the immersion time of the hollow fiber type filtration membrane in the sterilizing agent is long, the membrane can be washed without using a useless sterilizing agent. Therefore, it is possible to reduce the use amount of the bactericide, and it is possible to reduce not only the cost but also the influence on the environment.
【図１】 本発明による天然水の膜浄化方法を実施する
ための浄化装置の一例を示す。FIG. 1 shows an example of a purification device for carrying out a method for purifying a natural water membrane according to the present invention.
【図２】 天然水の水浄化における本発明及び参考発明
の実施結果を示した図である。FIG. 2 is a diagram showing the results of implementing the present invention and the reference invention in the purification of natural water.
１０ 逆止弁 １１ 原水供給ポンプ １２ 中空糸型の濾過膜モジュール １４ 洗浄水排出自動弁 １５ 逆洗水排出経路 １６ 循環経路 １７ 透過水タンク １８ 逆洗水供給ポンプ １９ 逆洗自動弁 ２１ 薬剤タンク ２２ 薬剤供給ポンプ ２５ 薬剤自動弁 DESCRIPTION OF SYMBOLS 10 Check valve 11 Raw water supply pump 12 Hollow fiber type filtration membrane module 14 Washing water discharge automatic valve 15 Backwash water discharge path 16 Circulation path 17 Permeated water tank 18 Backwash water supply pump 19 Backwash automatic valve 21 Chemical tank 22 Drug supply pump 25 Automatic drug valve
───────────────────────────────────────────────────── フロントページの続き (72)発明者 阿瀬 智暢 神奈川県横浜市戸塚区平戸３−20−１− 403 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tomonori Ase 403 3-2-1-1 Hirado, Totsuka-ku, Yokohama-shi, Kanagawa
Claims (1)
ールを用いて天然水を濾過する天然水の膜浄化方法にお
いて、中空糸型の濾過膜モジュールを殺菌剤を含む逆洗
水により逆洗する操作と、その直後に濾過処理を休止す
る操作からなる逆洗過程を設けることを特徴とする天然
水の膜浄化方法。1. A method for purifying natural water using a hollow fiber type ultrafiltration or microfiltration membrane module to purify natural water, wherein the hollow fiber type filtration membrane module is backwashed with backwash water containing a disinfectant. A method for purifying natural water membranes, comprising a backwashing process comprising an operation of performing a washing operation and an operation of immediately stopping the filtration treatment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001103072A JP2001300530A (en) | 2001-04-02 | 2001-04-02 | Method of purifying natural water with membrane |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001103072A JP2001300530A (en) | 2001-04-02 | 2001-04-02 | Method of purifying natural water with membrane |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP03174795A Division JP3194684B2 (en) | 1995-01-27 | 1995-01-27 | Natural water membrane purification method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2001300530A true JP2001300530A (en) | 2001-10-30 |
Family
ID=18956184
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001103072A Pending JP2001300530A (en) | 2001-04-02 | 2001-04-02 | Method of purifying natural water with membrane |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2001300530A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007105644A (en) * | 2005-10-14 | 2007-04-26 | Hitachi Ltd | Operation controller and operation support device of membrane filtration apparatus |
| JP2007237016A (en) * | 2006-03-06 | 2007-09-20 | Daicen Membrane Systems Ltd | Seawater filtering method |
| WO2019171956A1 (en) * | 2018-03-05 | 2019-09-12 | 栗田工業株式会社 | Method for cleaning membrane separation apparatus |
-
2001
- 2001-04-02 JP JP2001103072A patent/JP2001300530A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007105644A (en) * | 2005-10-14 | 2007-04-26 | Hitachi Ltd | Operation controller and operation support device of membrane filtration apparatus |
| JP2007237016A (en) * | 2006-03-06 | 2007-09-20 | Daicen Membrane Systems Ltd | Seawater filtering method |
| WO2019171956A1 (en) * | 2018-03-05 | 2019-09-12 | 栗田工業株式会社 | Method for cleaning membrane separation apparatus |
| JP2019150789A (en) * | 2018-03-05 | 2019-09-12 | 栗田工業株式会社 | Washing method of membrane separator |
| CN111565825A (en) * | 2018-03-05 | 2020-08-21 | 栗田工业株式会社 | Method for cleaning membrane separation device |
| CN111565825B (en) * | 2018-03-05 | 2021-09-10 | 栗田工业株式会社 | Method for cleaning membrane separation device |
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