JP2500181B2 - Backwashing method for ceramic membrane - Google Patents
Backwashing method for ceramic membraneInfo
- Publication number
- JP2500181B2 JP2500181B2 JP4243355A JP24335592A JP2500181B2 JP 2500181 B2 JP2500181 B2 JP 2500181B2 JP 4243355 A JP4243355 A JP 4243355A JP 24335592 A JP24335592 A JP 24335592A JP 2500181 B2 JP2500181 B2 JP 2500181B2
- Authority
- JP
- Japan
- Prior art keywords
- ceramic membrane
- membrane
- backwashing
- filtration
- pressurized air
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Separation Using Semi-Permeable Membranes (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、濾過用の膜分離装置に
使用されるマルチチャンネル型のセラミック膜の逆洗方
法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of backwashing a multi-channel type ceramic membrane used in a membrane separation device for filtration.
【０００２】[0002]
【従来の技術】多孔質セラミックよりなる支持層に多数
の孔を形成して孔の表面に親水性の分離層を形成したマ
ルチチャンネル型のセラミック膜は、ＵＦ膜（限外濾過
膜）やＭＦ膜（精密濾過膜）として水処理やバイオリア
クター等の分野で広く使用されている。そしてこのよう
なマルチチャンネル型のセラミック膜が使用により次第
に目詰まりして濾過能力が低下したときには、逆洗（逆
圧洗浄）によって膜表面に堆積したケーキ層や分離層の
表層部の閉塞物を除去するのが普通である。2. Description of the Related Art A multi-channel type ceramic membrane in which a large number of pores are formed in a support layer made of a porous ceramic and a hydrophilic separation layer is formed on the surface of the pores is a UF membrane (ultrafiltration membrane) or MF. It is widely used as a membrane (microfiltration membrane) in the fields of water treatment and bioreactors. When such a multi-channel type ceramic membrane is gradually clogged due to its use and the filtration capacity is reduced, backwashing (backpressure washing) removes cakes on the surface of the membrane and blockages on the surface layer of the separation layer. It is usually removed.
【０００３】従来この逆洗は、膜によって濾過された透
過水を加圧タンク等に貯えておき、この透過水をポンプ
や加圧エアーによって逆流させる方法で行われている。
しかしそのためには膜により濾過された透過水を逆流さ
せるために濾過液の回収率が低下するという問題がある
ほか、逆洗用に透過水を一定量溜めておく必要があるの
で、この部分での細菌増殖による膜の透過側空間の汚染
が懸念されるうえ、加圧タンクや逆洗のためのポンプが
余分に必要となる等の問題もあった。また、透過水単独
で逆洗を行うと、支持層部の通水抵抗によってマルチチ
ャンネルの中心付近の孔では十分な逆洗効果が得られな
いおそれがあった。Conventionally, this backwashing is carried out by a method in which permeated water filtered by a membrane is stored in a pressure tank or the like, and the permeated water is backflowed by a pump or pressurized air.
However, in order to do so, there is a problem that the permeated water filtered by the membrane flows back and the recovery rate of the filtrate decreases, and it is necessary to store a certain amount of permeated water for backwashing. There is a concern that the permeation side space of the membrane may be contaminated due to the bacterial growth, and a pressure tank and a pump for backwashing are additionally required. Further, when backwashing with permeated water alone, there is a possibility that sufficient backwashing effect may not be obtained in the holes near the center of the multi-channel due to water resistance of the support layer portion.
【０００４】[0004]
【発明が解決しようとする課題】本発明は上記した従来
の問題点を解決して、透過水の回収率を低下させたり透
過側空間の汚染を招くことなく膜を逆洗することがで
き、またマルチチャンネルの全ての孔をまんべんなく逆
洗でき、さらに逆洗のための加圧タンクやポンプを付設
する必要のないセラミック膜の逆洗方法を提供するため
になされたものである。SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems and enables backwashing of a membrane without lowering the recovery rate of permeate or causing contamination of the permeate side space. Further, the present invention has been made to provide a method for backwashing a ceramic membrane, which can evenly backwash all the holes of a multi-channel and which does not require a pressure tank or pump for backwashing.
【０００５】[0005]
【課題を解決するための手段】上記の課題を解決するた
めになされた本発明は、多孔質セラミックよりなる支持
層の表面に親水性の分離層を形成したマルチチャンネル
型のセラミック膜の濾過能力が低下した際、セラミック
膜の透過水側に加圧エアを導入することにより、濾過容
器内の透過水やエレメント内部の含有水のみをセラミッ
ク膜の内部で濾過方向とは逆向きに流し、エレメント内
部の含有水を加圧エアにより完全に押し切って逆洗する
ことを特徴とするものである。DISCLOSURE OF THE INVENTION The present invention, which has been made to solve the above-mentioned problems, has a filtering ability of a multi-channel type ceramic membrane in which a hydrophilic separation layer is formed on the surface of a support layer made of a porous ceramic. When the air flow rate drops, by introducing pressurized air to the permeated water side of the ceramic membrane, only the permeated water in the filtration container and the water contained in the element are made to flow in the ceramic membrane in the direction opposite to the filtration direction. It is characterized in that the contained water in the interior is completely pressed down by pressurized air and backwashed.
【０００６】[0006]
【実施例】以下に本発明を図示の実施例とともに更に詳
細に説明する。図１において、１は濾過容器、２はその
内部に設置された内圧式マルチチャンネル型のセラミッ
ク膜、３は濾過容器１とセラミック膜２との間をシール
するＯリング、４はセラミック膜２よって濾過された透
過水を管路５を通じて外部へ取り出すための透過水排出
弁、６はこの管路５に加圧エアを導入するためのエア導
入弁、７はエアー抜き弁である。The present invention will be described in more detail below with reference to the illustrated embodiments. In FIG. 1, 1 is a filtration container, 2 is an internal pressure type multi-channel type ceramic membrane installed therein, 3 is an O-ring for sealing between the filtration container 1 and the ceramic membrane 2, and 4 is a ceramic membrane 2. A permeated water discharge valve for taking out the filtered permeated water to the outside through the conduit 5, 6 is an air introduction valve for introducing pressurized air into the conduit 5, and 7 is an air vent valve.
【０００７】図２はその水平断面図であり、右下の枠内
にその一部を拡大して示した。セラミック膜２は、アル
ミナ等の多孔質セラミックよりなる支持層2aに形成され
た多数の孔の表面に親水性の分離層2bを形成した非対称
構造のマルチチャンネル型のもので、例えば支持層2aの
厚みが0.5 〜３mm、支持層2aの細孔径が１〜100 μm 、
分離層2bの厚みが0.1 〜１μm 、その孔径が10Å〜１μ
m 程度のものが使用されている。FIG. 2 is a horizontal sectional view thereof, and a part thereof is enlarged and shown in a lower right frame. The ceramic membrane 2 is an asymmetric multi-channel type in which a hydrophilic separation layer 2b is formed on the surface of a large number of pores formed in a support layer 2a made of a porous ceramic such as alumina. The thickness is 0.5 to 3 mm, the pore diameter of the support layer 2a is 1 to 100 μm,
The separation layer 2b has a thickness of 0.1-1 μm and a pore diameter of 10Å-1 μm.
Something about m is used.
【０００８】図１は濾過中の状態を示すもので、濾過容
器１に原水を供給してマルチチャンネル型のセラミック
膜２の内部から外部に向けて原水を流して濾過を行わ
せ、透過水は管路５の透過水排出弁４を通じて取り出さ
れている。この間、エア導入弁６は閉じられている。こ
のような濾過を継続する間に、セラミック膜２の表面に
は次第にケーキ層や閉塞物の層が形成され、濾過能力が
低下する傾向を示す。なお、右下の枠内に図２と同様に
一部を拡大して示した。FIG. 1 shows a state during filtration. Raw water is supplied to the filtration container 1 to flow the raw water from the inside of the multi-channel type ceramic membrane 2 to the outside to carry out filtration. It is taken out through the permeated water discharge valve 4 of the pipe line 5. During this time, the air introduction valve 6 is closed. While such filtration is continued, a cake layer or a layer of blockages is gradually formed on the surface of the ceramic membrane 2, and the filtration ability tends to decrease. It should be noted that a part is enlarged and shown in the lower right frame as in FIG.
【０００９】このようにして逆洗が必要となったとき、
図３のように管路５の透過水排出弁４を閉じたうえ、エ
ア導入弁６を開いてセラミック膜２の透過水側に加圧エ
アを導入する。図３の状態ではこの加圧エアの圧力によ
って透過水がセラミック膜２の内部を濾過方向とは逆向
きに流れる。またセラミック膜２の支持層の含有水も同
時に逆向きに流れ、セラミック膜２の表面のケーキ層や
閉塞物を剥離する。更にエレメントの支持層2a内に加圧
エアーが達しマルチチャンネルの中心部の孔まで十分に
加圧逆洗し、支持層2a内の含有透過水を全量押し切る。
また剥離された物質は原水とともに上方に排出される。
図４は管路５に導入された加圧エアがセラミック膜２の
表面まで達した状態を示している。When backwashing becomes necessary in this way,
As shown in FIG. 3, the permeated water discharge valve 4 of the conduit 5 is closed, and the air introduction valve 6 is opened to introduce pressurized air to the permeated water side of the ceramic membrane 2. In the state of FIG. 3, the pressure of the pressurized air causes the permeated water to flow inside the ceramic membrane 2 in the direction opposite to the filtration direction. Further, the water contained in the supporting layer of the ceramic membrane 2 also flows in the opposite direction at the same time, and the cake layer and the blockages on the surface of the ceramic membrane 2 are peeled off. Further, pressurized air reaches the support layer 2a of the element and sufficiently backwashes the holes in the center of the multi-channel under pressure to completely remove the permeated water contained in the support layer 2a.
The separated substances are discharged upward together with the raw water.
FIG. 4 shows a state in which the pressurized air introduced into the conduit 5 reaches the surface of the ceramic membrane 2.
【００１０】セラミック膜の孔径Ｄとそこを通過するエ
アー圧力Ｐの関係は、次の表１に表される。従って、0.
1kg/cm2 以上の圧力があれば支持層2a内にエアーは進入
していくことができる。上限圧力については使用する膜
の分離孔径 (最大気孔径) によって決まるが、高分子膜
とは異なり孔径分布が極めてシャープなセラミック膜に
おいては、分離孔径の５倍の孔径のバブルポイントをと
れば、分離層をエアーが透過することはほとんどない。
よって上限圧力Ｐmax は、Ｐmax ＝3/(5D)で近似的に表
される。実施例の0.1 μm の膜の場合、上式より6kg/cm
2 以下の圧力であればエレメント内に進入したエアーは
セラミック膜２の支持層2a内に容易に進入し、その含有
水を加圧して分離層2bに逆流させるが、エアー自体は親
水性の分離層2bを通過することはできない。このために
加圧エアがセラミック膜２の表面まで達しても、原水側
に加圧エアが侵入するおそれはない。The relationship between the pore diameter D of the ceramic membrane and the air pressure P passing through it is shown in Table 1 below. Therefore, 0.
If the pressure is 1 kg / cm 2 or more, the air can enter into the support layer 2a. The upper limit pressure is determined by the separation pore size (maximum pore size) of the membrane to be used, but in the case of a ceramic membrane, which has an extremely sharp pore size distribution, unlike a polymer membrane, if the bubble point of 5 times the separation pore size is taken, Air hardly penetrates the separation layer.
Therefore, the upper limit pressure P max is approximately represented by P max = 3 / (5D). In the case of the 0.1 μm membrane of the example, 6 kg / cm from the above formula
If the pressure is 2 or less, the air that has entered the element easily enters the support layer 2a of the ceramic membrane 2 and pressurizes the contained water to flow back into the separation layer 2b, but the air itself is hydrophilic. It cannot pass through layer 2b. Therefore, even if the pressurized air reaches the surface of the ceramic membrane 2, there is no possibility that the pressurized air will enter the raw water side.
【００１１】[0011]
【表１】 [Table 1]
【００１２】このようにして逆洗が完了したら、図５に
示すようにエア導入弁６を閉じるとともに透過水排出弁
４を開き、濾過を再開する。なおこのときには管路５の
内部に加圧エアが溜まっているため、適宜の空気排出弁
を通じて排気を行いつつ濾過液の取り出しを行うものと
する。When the backwash is completed in this way, the air introduction valve 6 is closed and the permeated water discharge valve 4 is opened as shown in FIG. 5 to restart the filtration. At this time, since the pressurized air is accumulated inside the conduit 5, the filtered liquid is taken out while exhausting through an appropriate air exhaust valve.
【００１３】[0013]
【発明の効果】以上に説明したように、本発明のセラミ
ック膜の逆洗方法は、セラミック膜の透過水側に加圧エ
アを導入することにより、透過水やエレメント内部の含
有水のみをセラミック膜の内部で濾過方向とは逆向きに
流して逆洗するものであるから、次の通りの優れた効果
を得ることができる。 マルチチャンネル型のセラミック膜の場合、透過水
単独での逆洗では支持層の通水抵抗によって中心部の孔
と外周部の孔では逆洗効果が大きく異なるが、エアーの
場合は水に比べて抵抗が極めて小さいため、中心部の孔
の周囲の含有水も十分に加圧し、逆洗することができ
る。 従来のような逆洗用の加圧タンクやポンプを付設す
る必要がなく、設備を簡素化することができる。 加圧エアは水などの液体に比較して粘度、密度とも
に極めて小さいため、僅かな圧力損失でフィルターをか
けることができる。このため除菌が容易であり、また逆
洗のための濾過液を貯留する必要がないことから、逆洗
による透過側空間の細菌汚染のおそれがない。 逆洗はごく少量の透過水によって行われるので、透
過水の回収率を低下させることなく膜を逆洗することが
できる。 瞬間的な加圧逆洗が可能であり、逆洗に伴う濾過の
停止時間を最小限とすることができる。As described above, in the backwashing method for the ceramic membrane of the present invention, only the permeated water or the water contained in the element is introduced into the ceramic membrane by introducing pressurized air into the permeated water side of the ceramic membrane. Since the membrane is flushed in the direction opposite to the filtration direction and backwashed, the following excellent effects can be obtained. In the case of a multi-channel type ceramic membrane, the backwashing effect of the permeate alone differs greatly between the central hole and the outer holes due to the water resistance of the support layer. Since the resistance is extremely low, it is possible to sufficiently pressurize the water contained around the hole in the central portion and backwash it. It is not necessary to attach a pressure tank or pump for backwashing as in the conventional case, and the equipment can be simplified. Since pressurized air has extremely low viscosity and density as compared with liquids such as water, it can be filtered with a slight pressure loss. Therefore, bacteria can be easily removed, and since it is not necessary to store the filtrate for backwashing, there is no risk of bacterial contamination of the permeate side space due to backwashing. Since backwashing is performed with a very small amount of permeated water, the membrane can be backwashed without lowering the recovery rate of permeated water. Instantaneous pressure backwashing is possible, and the stop time of filtration accompanying backwashing can be minimized.
【図１】濾過中の状況を説明する断面図である。FIG. 1 is a cross-sectional view illustrating a situation during filtration.
【図２】装置の水平断面図である。FIG. 2 is a horizontal sectional view of the device.
【図３】逆洗を開始し、加圧エアが導入された瞬間の状
況を説明する断面図である。FIG. 3 is a cross-sectional view illustrating a situation at the moment when backwashing is started and pressurized air is introduced.
【図４】逆洗のための加圧エアがセラミック膜の支持層
に達した状態を説明する断面図である。FIG. 4 is a cross-sectional view illustrating a state where pressurized air for backwashing reaches a supporting layer of a ceramic membrane.
【図５】逆洗が終了して濾過を再開した状態を説明する
断面図である。FIG. 5 is a cross-sectional view illustrating a state in which backwashing is completed and filtration is restarted.
１ 濾過容器 ２ マルチチャンネル型のセラミック膜 ３ Ｏリング ４ 透過水排出弁 ５ 管路 ６ エア導入弁 ７ エアー抜き弁 1 Filtration container 2 Multi-channel type ceramic membrane 3 O-ring 4 Permeate discharge valve 5 Pipe line 6 Air introduction valve 7 Air vent valve
Claims (1)
に親水性の分離層を形成したマルチチャンネル型のセラ
ミック膜の濾過能力が低下した際、セラミック膜の透過
水側に加圧エアを導入することにより、透過水やエレメ
ント内部の含有水のみをセラミック膜の内部で濾過方向
とは逆向きに流し、エレメント内部の含有水を加圧エア
により完全に押し切って逆洗することを特徴とするセラ
ミック膜の逆洗方法。1. Pressurized air is introduced into the permeate side of the ceramic membrane when the filtration capacity of the multi-channel ceramic membrane in which a hydrophilic separation layer is formed on the surface of a porous ceramic support layer is reduced. As a result, only the permeated water and the water contained inside the element are made to flow in the ceramic membrane in the direction opposite to the filtration direction, and the water contained inside the element is completely pressed back by the pressurized air and backwashed. How to backwash the membrane.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4243355A JP2500181B2 (en) | 1992-09-11 | 1992-09-11 | Backwashing method for ceramic membrane |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4243355A JP2500181B2 (en) | 1992-09-11 | 1992-09-11 | Backwashing method for ceramic membrane |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0751548A JPH0751548A (en) | 1995-02-28 |
| JP2500181B2 true JP2500181B2 (en) | 1996-05-29 |
Family
ID=17102607
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4243355A Expired - Lifetime JP2500181B2 (en) | 1992-09-11 | 1992-09-11 | Backwashing method for ceramic membrane |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2500181B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8641904B2 (en) | 2004-05-13 | 2014-02-04 | Metawater Co., Ltd. | Method for membrane backwashing and backwashing apparatus |
| WO2007004261A1 (en) * | 2005-06-30 | 2007-01-11 | Ngk Insulators, Ltd. | Filter |
| JP6074281B2 (en) * | 2013-02-04 | 2017-02-01 | メタウォーター株式会社 | Membrane filtration system |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02227123A (en) * | 1989-02-28 | 1990-09-10 | Material Eng Tech Lab Inc | Microfiltration element |
| JP2794304B2 (en) * | 1989-05-24 | 1998-09-03 | 日東電工株式会社 | Cleaning method for hollow fiber membrane module |
| JP2873587B2 (en) * | 1989-08-18 | 1999-03-24 | 東芝セラミックス株式会社 | Liquid reforming method and apparatus |
-
1992
- 1992-09-11 JP JP4243355A patent/JP2500181B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0751548A (en) | 1995-02-28 |
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