JP2007111576A - Back-washing method of membrane module - Google Patents

Back-washing method of membrane module Download PDF

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JP2007111576A
JP2007111576A JP2005302449A JP2005302449A JP2007111576A JP 2007111576 A JP2007111576 A JP 2007111576A JP 2005302449 A JP2005302449 A JP 2005302449A JP 2005302449 A JP2005302449 A JP 2005302449A JP 2007111576 A JP2007111576 A JP 2007111576A
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membrane module
membrane
primary side
raw water
water
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Junichi Hirota
淳一 廣田
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NGK Insulators Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently back-washing a membrane module which filters raw water in an upwardly-flow-type and dead-end system without using any flocculant. <P>SOLUTION: In the back-washing method of the membrane module, turbid substances sticking to the membrane surface are peeled off by making back-washing water flow from a secondary side of the membrane to a primary side as done in the past in a monolithic type ceramic membrane module 1 in the upwardly-flow and dead-end-filtering system, and the peeled-off turbid substances are discharged from the upper part of the primary side of the membrane module by feeding raw water from the lower part of the primary side of the membrane module at the linear flow velocity of 50 cm/sec or less in the cell of the ceramic membrane with a valve 2 open in the upper part of the primary side of the membrane module 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、上水や下水のろ過に用いられる膜モジュールの逆洗方法に関するものであり、特に上向流デッドエンドろ過を行なう膜モジュールの逆洗方法に関するものである。   The present invention relates to a back washing method for a membrane module used for filtration of clean water and sewage, and more particularly to a back washing method for a membrane module for performing an upflow dead-end filtration.

膜モジュールを用いて原水をろ過する方法には、膜モジュールの一次側で原水を循環させながらその一部をろ過するクロスフロー方式と、膜モジュールの一次側に供給した原水の全量をろ過するデッドエンド方式とがある。
また膜モジュールの種類も多くあるが、出願人会社にて生産しているモノリス型のセラミック膜モジュールは膜の耐久性に優れ、細菌類を完全にろ過することができるので、上水製造手段として実用化されている。 There are two methods for filtering raw water using a membrane module: a cross-flow method in which raw water is circulated on the primary side of the membrane module and part of the raw water supplied to the primary side of the membrane module. There is an end system.
There are also many types of membrane modules, but the monolithic ceramic membrane modules produced by the applicant company have excellent membrane durability and can completely filter bacteria. It has been put into practical use.

このモノリス型のセラミック膜モジュールは、蓮根状の孔を持つモノリス型のセラミック膜を金属製の容器の内部に収納したもので、通常は垂直に設置され、下方から原水を供給する上向流デッドエンドろ過が行われている。図１はその説明図であり、１は膜モジュール、２はその内部に収納されたモノリス型のセラミック膜である。ろ過を行う場合は、まず原水供給ポンプ３を稼動するとともに、原水供給弁Ｖ−１、一次側上部排水弁Ｖ−２を開く事で、膜モジュール一次側を原水で満たし空気を追い出す水張り工程を実施する。ついで、一次側上部排水弁Ｖ−２を閉じ、ろ過水弁Ｖ−３を開く事で、デッドエンドろ過が開始され、ろ過水がえられる。また、この時、定流量ろ過を行う場合には、通常インバータ等の回転数制御装置４でポンプを制御する。   This monolithic ceramic membrane module is a monolithic ceramic membrane with lotus root-like holes housed inside a metal container, usually installed vertically, and an upflow dead that supplies raw water from below End filtration is performed. FIG. 1 is an explanatory diagram thereof, 1 is a membrane module, and 2 is a monolithic ceramic membrane housed therein. When performing filtration, first, the raw water supply pump 3 is operated, and the raw water supply valve V-1 and the primary side upper drain valve V-2 are opened to fill the membrane module primary side with raw water and expel air. carry out. Next, by closing the primary side upper drain valve V-2 and opening the filtered water valve V-3, dead-end filtration is started and filtered water is obtained. At this time, when performing constant flow filtration, the pump is usually controlled by the rotation speed control device 4 such as an inverter.

しかしこのようなろ過運転を継続すると、原水中の濁質が次第に膜面に堆積し、膜モジュールの膜差圧が上昇することが避けられない。そこで、ろ過工程時に、ろ過水弁Ｖ−３を閉じると同時に、逆洗水弁Ｖ−４を開く事で、あらかじめ、ろ過水を逆洗タンク５に溜めておき、所定の膜差圧もしくはろ過時間に達したところで、溜めておいたろ過水を膜モジュールの二次側から一次側へ押し流して膜面に付着している濁質を剥離させる逆洗を実施する。逆洗は、原水供給ポンプ３及び全ての弁を閉じる事でろ過を停止した後、逆洗空気弁Ｖ−５を開く事で、高圧空気源６から高圧空気を供給し逆洗タンク５を加圧する。次に逆洗水弁Ｖ−４を開く事で、膜モジュール二次側を加圧、保持する。ついで、逆洗排水弁Ｖ−６を開き、加圧されたろ過水を二次側から一次側へ押し流す。   However, if such a filtration operation is continued, turbidity in the raw water gradually accumulates on the membrane surface, and it is inevitable that the membrane differential pressure of the membrane module increases. Therefore, at the same time as the filtration step, the filtered water valve V-3 is closed and at the same time the backwash water valve V-4 is opened, so that the filtrate is stored in the backwash tank 5 in advance, and a predetermined membrane differential pressure or filtration is performed. When the time has been reached, backwashing is performed in which the collected filtered water is pushed from the secondary side of the membrane module to the primary side to remove turbidity adhering to the membrane surface. In backwashing, filtration is stopped by closing the raw water supply pump 3 and all the valves, and then the backwash air valve V-5 is opened to supply high pressure air from the high pressure air source 6 and add the backwash tank 5 to the backwash. Press. Next, by opening the backwash valve V-4, the membrane module secondary side is pressurized and held. Next, the backwash drain valve V-6 is opened, and the pressurized filtrate is pushed away from the secondary side to the primary side.

このとき大量の逆洗水を使用すれば、膜面から剥離した濁質を膜モジュール１の外部に排出することができる。しかし逆洗水としてろ過水を使用するので、大量の逆洗水の使用は水回収率の低下を招く。このため特許文献１に示されるように、上述の逆洗時に、あわせてエアブロー弁Ｖ−７を開く事で、高圧空気源６から高圧空気を膜モジュールの一次側にも供給し、二次側からの水逆洗と一次側のエアブローを組み合わせている。これにより、二次側から一次側へ押し流された水を、一次側に供給された空気によって逆洗排水弁Ｖ−６から外部へ排出することができるので、逆洗水量が少なくなるとともに、空気のせん断力で膜面の濁質を剥ぎ取る効果があわせて期待できる。したがって、この方法は、多くの浄水施設で標準的な逆洗方法となっている。
特開平７−２５１０４１号公報 At this time, if a large amount of backwash water is used, the suspended matter separated from the membrane surface can be discharged to the outside of the membrane module 1. However, since filtered water is used as the backwash water, the use of a large amount of backwash water causes a reduction in the water recovery rate. For this reason, as shown in Patent Document 1, by opening the air blow valve V-7 together with the above-described backwashing, high pressure air is also supplied from the high pressure air source 6 to the primary side of the membrane module, and the secondary side Combined with water backwash from the primary air blow. Thereby, since the water pushed away from the secondary side to the primary side can be discharged to the outside from the backwash drain valve V-6 by the air supplied to the primary side, the amount of backwash water is reduced and the air The effect of peeling off the turbidity on the film surface with the shearing force can be expected. Therefore, this method is a standard backwash method in many water purification facilities.
JP-A-7-251041

ところが、地下水や河川上澄水のような清澄水を原水とし、凝集剤を使用せずに膜ろ過する場合や、下水であっても凝集剤を使用する必要のない場合などにおいては、上向流デッドエンドろ過を行なう膜モジュールの逆洗に上記の水逆洗とエアブローとを組み合わせる方法を繰り返し実施すると、次第に逆洗効果が低下してしまうことが判明した。このため膜差圧を十分に低下させることができなくなり、装置全体を停止して薬液洗浄を行なわねばならず、設備稼働率の低下を招くこととなる。   However, when the raw water is clarified water, such as groundwater or river supernatant, and the membrane is filtered without using a flocculant, or when sewage does not require the use of a flocculant, the upward flow It has been found that if the above-described method of combining water backwashing and air blow is repeated for backwashing of a membrane module that performs dead-end filtration, the backwashing effect gradually decreases. For this reason, it becomes impossible to sufficiently reduce the membrane differential pressure, and the entire apparatus must be stopped to perform chemical cleaning, leading to a reduction in equipment operation rate.

従って本発明の目的は、凝集剤を使用せずに原水を上向流デッドエンドろ過する膜モジュールを、効果的に逆洗することができる膜モジュールの逆洗方法を提供することである。   Accordingly, an object of the present invention is to provide a method for backwashing a membrane module that can effectively backwash a membrane module that performs upward flow dead-end filtration of raw water without using a flocculant.

上記の課題を解決するために、本発明者は従来技術の問題点を様々な角度から検討した結果、従来は逆洗効果を高めるために必須と考えられていたエアブローが、却って膜差圧の低下を阻害するケースが存在することを究明した。すなわち、上向流デッドエンドろ過を行う膜モジュールでは、長期間の使用により膜面だけでなく容器内の上部にも濁質が溜まっているが、エアブローを行なうことによってこの濁質が逆に膜面に付着する場合があること、膜面に付着している濁質が空気との接触により変質して詰まる場合があること、エアブローを行なうことによって膜面に微細な気泡が入り込み、有効膜面積が減少してしまう場合があることなどが明らかになった。これらは、凝集剤を使用しない無凝集ろ過においては、ろ過で阻止される濁質の粒径が非常に細かい為、エアブローにより得られる効果が小さくなる事に起因すると考えられる。   In order to solve the above-mentioned problems, the present inventor has examined the problems of the prior art from various angles, and as a result, air blow, which was conventionally considered essential for enhancing the backwashing effect, We have determined that there are cases that inhibit the decline. In other words, in membrane modules that perform upflow dead-end filtration, turbidity accumulates not only on the membrane surface but also in the upper part of the container due to long-term use. There are cases where it adheres to the surface, turbidity adhering to the membrane surface may change due to contact with air and clog it, and air bubbles blow fine air bubbles into the membrane surface, resulting in an effective membrane area. It became clear that there might be a decrease. These are considered to be due to the fact that the effect obtained by air blowing is reduced because the particle size of turbidity blocked by filtration is very fine in non-aggregation filtration without using a flocculant.

本発明はこのような新たな知見に基づいてなされたものであって、上向流デッドエンドろ過を行なう膜モジュールにおいて、先ず膜モジュールへの原水の供給を停止し、膜の二次側から一次側に逆洗水を流して膜面に付着している濁質を剥離させたうえ、膜モジュール一次側上部の弁を開放して原水を膜モジュール一次側の下方から供給し、剥離した濁質を膜モジュール一次側上部から排出することを特徴とするものである。   The present invention has been made on the basis of such new knowledge, and in a membrane module that performs upflow dead-end filtration, first, the supply of raw water to the membrane module is stopped, and the primary side from the secondary side of the membrane The turbidity adhering to the membrane surface is made to flow by flowing backwash water to the side, the valve on the primary side of the membrane module is opened, and raw water is supplied from the lower side of the membrane module primary side. Is discharged from the upper part of the primary side of the membrane module.

なお、上向流デッドエンドろ過を行う膜モジュールが、モノリス型のセラミック膜を使用し、膜モジュール一次側の下方からの原水の供給を、セラミック膜のセル内線速を50cm/sec以下の流速で行なうことが好ましい。なお、ここでいうセラミック膜のセルとは、蓮根状の貫通孔を意味する。すなわち、セラミック膜の蓮根状の貫通孔内部の線速が、50cm/sec以下であることが好ましい。   The membrane module that performs upflow dead-end filtration uses a monolithic ceramic membrane, and the supply of raw water from the lower side of the membrane module primary side is performed at a linear velocity in the cell of the ceramic membrane of 50 cm / sec or less. It is preferable to do so. Here, the cell of the ceramic film means a lotus root-like through hole. That is, it is preferable that the linear velocity inside the lotus-shaped through hole of the ceramic film is 50 cm / sec or less.

本発明の膜モジュールの逆洗方法によれば、上向流デッドエンドろ過を行なう膜モジュールの膜差圧が上昇した際に、通常の水逆洗を行なった後にエアブローは行なわず、膜モジュール一次側上部の弁を開放して原水を膜モジュール一次側の下方から供給し、剥離した濁質を膜モジュール一次側上部から排出する。このため濁質や膜面に空気が接触するおそれが無く、容器内の上部に溜まっていた濁質が膜面に付着したり、膜面に付着している濁質が空気との接触により変質したり、膜面に微細な気泡が入り込み、有効膜面積が減少したりするおそれがない。   According to the membrane module backwashing method of the present invention, when the membrane differential pressure of the membrane module performing the upflow dead-end filtration is increased, the air blow is not performed after the normal water backwashing, and the membrane module primary The valve on the upper side is opened and raw water is supplied from the lower side of the membrane module primary side, and the separated turbidity is discharged from the upper side of the membrane module primary side. For this reason, there is no risk of air coming into contact with the turbidity or the membrane surface, and the turbidity accumulated in the upper part of the container adheres to the membrane surface, or the turbidity adhering to the membrane surface changes due to contact with air. There is no risk that the bubbles will enter the surface of the membrane and the effective membrane area may be reduced.

しかも膜面から剥離した濁質や、容器内の上部に溜まっていた濁質は膜モジュール一次側上部から排出される。本発明は特に凝集剤を使用せずに原水を上向流デッドエンドろ過する膜モジュールに適した方法である。   Moreover, the turbidity separated from the membrane surface and the turbidity accumulated in the upper part of the container are discharged from the upper part of the membrane module primary side. The present invention is a method particularly suitable for a membrane module that performs upstream flow dead-end filtration of raw water without using a flocculant.

以下に本発明の好ましい実施形態を示す。
図２において、１は膜モジュール、２はその内部に収納されたモノリス型のセラミック膜である。前記したようにモノリス型のセラミック膜は蓮根状の多数の貫通孔を備えたもので、その内周面がろ過膜となっている。本発明では、後述するように、通常の逆洗後に膜モジュール一次側が空（水に満たされていない状態）になることがないので、従来の水張り工程が不要となり、基本的にろ過を行う場合は、原水供給ポンプ３を稼動するとともに、原水供給弁Ｖ−１、ろ過水弁Ｖ−３を開くだけで、デッドエンドろ過が開始され、ろ過水がえられる。また、この時、定流量ろ過を行う場合には、通常インバータ等の回転数制御装置４でポンプを制御するのは従来と同様である。また、供用開始時など、最初に水張り工程が必要な場合は従来と同様に実施すればよい。 Preferred embodiments of the present invention are shown below.
In FIG. 2, 1 is a membrane module, and 2 is a monolithic ceramic membrane housed therein. As described above, the monolithic ceramic membrane has many lotus-like through holes, and the inner peripheral surface thereof is a filtration membrane. In the present invention, as will be described later, since the primary side of the membrane module does not become empty (in a state not filled with water) after normal backwashing, the conventional water filling step is unnecessary, and basically filtration is performed. In addition to operating the raw water supply pump 3 and opening the raw water supply valve V-1 and the filtered water valve V-3, dead-end filtration is started and filtered water is obtained. At this time, when constant flow filtration is performed, the pump is normally controlled by the rotation speed control device 4 such as an inverter as in the conventional case. Moreover, what is necessary is just to implement similarly to the past, when a water-filling process is first required, such as at the start of service.

このようにして上向流デッドエンドろ過を行なう膜モジュール１の膜差圧が上昇した際には、従来と同様に、ろ過工程時に、ろ過水弁Ｖ−３を閉じ、逆洗水弁Ｖ−４を開く事で、あらかじめ、ろ過水を逆洗タンク５に溜めておき、所定の膜差圧もしくはろ過時間に達したところでろ過を停止し、ろ過水を膜モジュールの二次側から一次側へ押し流して膜面に付着している濁質を剥離させる逆洗を実施する。
原水供給ポンプ３及び全ての弁を閉じる事でろ過を停止した後、逆洗工程では、逆洗空気弁Ｖ−５を開く事で、高圧空気源６から高圧空気を供給し逆洗タンク５を加圧する。次に逆洗水弁Ｖ−４を開く事で、膜モジュール二次側を加圧、保持する。ついで、逆洗排水弁Ｖ−６を開き、加圧されたろ過水を二次側から一次側へ押し流すのも、従来と同様である。 Thus, when the membrane differential pressure of the membrane module 1 that performs the upflow dead-end filtration increases, the filtration water valve V-3 is closed and the backwash water valve V- By opening 4, filtered water is stored in the backwash tank 5 in advance, and filtration is stopped when a predetermined membrane differential pressure or filtration time is reached, and the filtered water is transferred from the secondary side to the primary side of the membrane module. Back washing is carried out to remove the turbidity adhering to the membrane surface.
After stopping the filtration by closing the raw water supply pump 3 and all the valves, in the backwashing process, by opening the backwash air valve V-5, high pressure air is supplied from the high pressure air source 6 and the backwash tank 5 is turned on. Pressurize. Next, by opening the backwash valve V-4, the membrane module secondary side is pressurized and held. Next, the backwash drain valve V-6 is opened and the pressurized filtered water is flushed from the secondary side to the primary side as in the conventional case.

しかし本発明では逆洗後に従来のようなエアブローは行なわず、一次側上部排水弁Ｖ−２を開き、原水供給ポンプ３を稼動し原水を膜モジュール１の一次側下方から供給する。これにより、剥離した濁質を膜モジュール１の一次側上部から排出する。この排水中の濁質は当然原水中よりもやや多いが、原水に戻してもろ過運転性及びろ過水質に支障をきたすことはない。従って、従来よりも逆洗排水量の低減も可能である。このとき、上向流デッドエンドろ過運転中に膜モジュール１の一次側上部に溜まっていた濁質も膜モジュール１の一次側上方から排出されるので、膜面に付着することはない。   However, in the present invention, air blow is not performed after backwashing, but the primary upper drain valve V-2 is opened, the raw water supply pump 3 is operated, and raw water is supplied from below the primary side of the membrane module 1. Thereby, the separated turbidity is discharged from the upper part of the primary side of the membrane module 1. Naturally, the turbidity in the wastewater is slightly higher than that in the raw water, but even if it is returned to the raw water, the filtration operability and the filtered water quality are not affected. Therefore, it is possible to reduce the amount of backwash drainage than before. At this time, the turbidity accumulated in the upper part of the primary side of the membrane module 1 during the upward flow dead-end filtration operation is also discharged from the upper side of the primary side of the membrane module 1 and therefore does not adhere to the membrane surface.

この原水の供給は、上向流デッドエンドろ過を行う膜モジュールが、モノリス型のセラミック膜を使用している場合は、セラミック膜のセル内線速を50cm/sec以下の流速で行なうことが好ましい。これ以上の線速は濁質の排出能力の向上と言う点では好ましいが、後述の実施例でも示すように、膜差圧の上昇を抑制する効果が小さくなる事が見出されている。さらに、これ以上の流速を要求すると、原水供給ポンプ３の能力を通常のろ過運転に使用する以上に高める必要があるため、実際的ではない。通常、この間の線速であれば、設計時に膜閉塞時でも定流量で稼動するようにポンプを選定している為、特に従来設計からポンプの能力を上げる必要もなく、コストの増加にはつながらない。 When the membrane module that performs the upflow dead-end filtration uses a monolithic ceramic membrane, the raw water is preferably supplied at a flow rate of 50 cm / sec or less in the cell of the ceramic membrane. A linear velocity higher than this is preferable in terms of improving the turbidity discharge capability, but it has been found that the effect of suppressing an increase in the membrane differential pressure is reduced, as will be shown in the examples described later. Furthermore, if a flow rate higher than this is required, it is not practical because it is necessary to increase the capacity of the raw water supply pump 3 beyond that used for normal filtration operation. Normally, if the linear speed is between these, the pump is selected so that it can be operated at a constant flow rate even when the membrane is clogged at the time of design. .

本発明によれば従来のようなエアブローを行わないので、濁質や膜面に空気が接触するおそれが無く、膜面に付着している濁質が空気との接触により変質したり、膜面に微細な気泡が入り込み、有効膜面積が減少したりするおそれがない。また、エアブロー弁Ｖ−７が不要となり、使用空気量も低減できる為コストが低減できる。しかも従来法では逆洗終了後の膜モジュール１の一次側は空（水で満たされていない状態）であるので、新たに膜モジュール１の一次側に原水を充満させる水張工程が必要であるが、本発明では逆洗終了後の膜モジュール１の一次側は原水で満たされているので、一次側上部排水弁Ｖ−２を閉じて直ちにろ過運転を再開できる利点がある。すなわち逆洗時間の短縮が可能となり、装置の稼働率が向上する。さらに、既述のように、一次側上部からの排出水は、濁質分が原水よりもやや多いが、原水に戻すことで、従来はエアブローにより逆洗排水として排出されていた膜モジュール一次側の水を原水側へ戻すことになるので、逆洗排水量の削減にもつながる。   According to the present invention, since conventional air blowing is not performed, there is no risk of air coming into contact with the turbidity or the membrane surface, and the turbidity adhering to the membrane surface may be altered by contact with air or the membrane surface. There is no risk that fine bubbles will enter the film and the effective membrane area will be reduced. Further, the air blow valve V-7 is not necessary, and the amount of air used can be reduced, so that the cost can be reduced. Moreover, in the conventional method, the primary side of the membrane module 1 after backwashing is empty (in a state where it is not filled with water), and therefore a water filling step for newly filling the primary side of the membrane module 1 with raw water is required. However, in the present invention, since the primary side of the membrane module 1 after backwashing is filled with raw water, there is an advantage that the filtration operation can be resumed immediately by closing the primary upper drain valve V-2. That is, the backwash time can be shortened and the operating rate of the apparatus is improved. Furthermore, as mentioned above, the effluent from the upper part of the primary side is slightly more turbid than the raw water, but by returning to the raw water, the membrane module primary side that was conventionally discharged as backwash wastewater by air blow Water will be returned to the raw water side, leading to a reduction in backwash drainage.

なお、凝集剤を混入した原水を上向流デッドエンドろ過を行なう場合には、本発明で得られる効果よりも、エアブローの実施による逆洗効果の方が大きい傾向がある為、むしろ従来のエアブロー方式を採用すべきである。   When raw water mixed with a flocculant is subjected to up-flow dead end filtration, the effect of backwashing by air blow tends to be greater than the effect obtained by the present invention. The method should be adopted.

モノリス型セラミック膜を使用した膜モジュールにて、伏流水を膜ろ過流速8ｍ3/ｍ2/日、ろ過時間6ｈｒにて、5系列並列ろ過運転した。
試験条件及び試験結果を表1にまとめる。本発明の逆洗後の膜モジュール一次側下方からの原水供給速度はセル内線速は2〜70ｃｍ/secとした。 In a membrane module using a monolithic ceramic membrane, the underground water was subjected to a 5-series parallel filtration operation at a membrane filtration flow rate of 8 m 3 / m 2 / day and a filtration time of 6 hours.
The test conditions and test results are summarized in Table 1. The raw water supply rate from the lower side of the membrane module primary side after backwashing according to the present invention was 2 to 70 cm / sec.

Figure 2007111576
Figure 2007111576

表1に付記した、膜差圧上昇速度（kPa/日）とは、１日あたりの膜差圧の上昇を表している。この値が大きくなれば、薬品洗浄周期が短くなり、コストの増加及び設備稼働率が低下する。   The membrane differential pressure increase rate (kPa / day) shown in Table 1 represents the increase in the membrane differential pressure per day. When this value is increased, the chemical cleaning cycle is shortened, resulting in an increase in cost and a reduction in equipment operation rate.

本試験結果では、従来法のエアブローありでは、膜差圧上昇速度が0.24kPa/日であったのに対し、本発明の実施例1〜3の様に、逆洗後の膜モジュール一次側下方からの原水供給速度をセル内線速は2から50ｃｍ/secと増加させることで、膜差圧上昇速度の低下が見られた。薬品洗浄周期で比較すると、実施例3では、従来法と比較して約3倍とすることが可能となった。また、実施例2、3では、膜差圧上昇速度の低減効果が小さい。また、実施例3、4でも低減効果は小さい。したがって、50ｃｍ/sec以上の線速の増加はポンプの能力アップ費用と得られる効果を考えると望ましくないと考えられた。   In this test result, with the air blow of the conventional method, the rate of increase in the membrane differential pressure was 0.24 kPa / day, whereas as in Examples 1 to 3 of the present invention, the membrane module primary side lower side after backwashing By increasing the raw water supply rate from 2 to 50 cm / sec, the rate of increase in membrane differential pressure was reduced. In comparison with the chemical cleaning cycle, in Example 3, it was possible to make about three times as compared with the conventional method. In Examples 2 and 3, the effect of reducing the rate of increase in the membrane differential pressure is small. Also, the reduction effect is small in Examples 3 and 4. Therefore, it was considered that an increase in the linear velocity of 50 cm / sec or more was not desirable in view of the cost for increasing the capacity of the pump and the obtained effect.

従来技術を示す断面図である。It is sectional drawing which shows a prior art. 本発明の実施形態を示す断面図である。It is sectional drawing which shows embodiment of this invention.

符号の説明Explanation of symbols

１ 膜モジュール
２ セラミック膜
３ 原水供給ポンプ
４ 回転数制御装置
５ 逆洗タンク
６ 高圧空気源
Ｖ−１ 原水供給弁
Ｖ−２ 一次側上部排水弁
Ｖ−３ ろ過水弁
Ｖ−４ 逆洗水弁
Ｖ−５ 逆洗空気弁
Ｖ−６ 逆洗排水弁
Ｖ−７ エアブロー弁 DESCRIPTION OF SYMBOLS 1 Membrane module 2 Ceramic membrane 3 Raw water supply pump 4 Rotational speed control device 5 Backwash tank 6 High pressure air source V-1 Raw water supply valve V-2 Primary side upper drain valve V-3 Filtration water valve V-4 Backwash water valve V-5 Backwash air valve V-6 Backwash drain valve V-7 Air blow valve

Claims (3)

上向流デッドエンドろ過を行なう膜モジュールの逆洗方法において、先ず膜モジュールへの原水の供給を停止し、膜の二次側から一次側に逆洗水を流して膜面に付着している濁質を剥離させたうえ、膜モジュール一次側上部の弁を開放して原水を膜モジュール一次側の下方から供給し、剥離した濁質を膜モジュール一次側上部から排出することを特徴とする膜モジュールの逆洗方法。   In the back washing method of the membrane module that performs the up-flow dead end filtration, first, the supply of raw water to the membrane module is stopped, and the back washing water flows from the secondary side of the membrane to the primary side and adheres to the membrane surface. Membrane characterized by separating the turbidity, opening the valve on the primary side of the membrane module, supplying raw water from below the primary side of the membrane module, and discharging the separated turbidity from the upper side of the primary side of the membrane module How to backwash modules. 上向流デッドエンドろ過を行う膜モジュールが、モノリス型のセラミック膜を使用していることを特徴とする請求項1記載の膜モジュールの逆洗方法。   2. The method for backwashing a membrane module according to claim 1, wherein the membrane module performing the upflow dead-end filtration uses a monolithic ceramic membrane. 膜モジュール一次側の下方からの原水の供給を、セラミック膜のセル内線速を50cm/sec以下の流速で行うことを特徴とする請求項１または２記載の膜モジュールの逆洗方法。   The method for backwashing a membrane module according to claim 1 or 2, wherein the raw water is supplied from below the primary side of the membrane module at a linear velocity in the cell of the ceramic membrane of 50 cm / sec or less.
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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102515312A (en) * 2011-12-21 2012-06-27 北京大学 Composite ceramic membrane-based filtration method and filtration device for cooling water produced in steel making and continuous casting
JP2018103170A (en) * 2016-12-22 2018-07-05 株式会社クボタ Membrane module operation method and membrane module
CN112403279A (en) * 2020-09-25 2021-02-26 浙江和达科技股份有限公司 Ceramic membrane filtering device and air-water combined backwashing method thereof
JP7541872B2 (en) 2020-08-24 2024-08-29 株式会社クボタ Method for backwashing a membrane separation device

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06190251A (en) * 1992-12-28 1994-07-12 Japan Organo Co Ltd Method and apparatus for treatment of water containing turbid component
JPH07178323A (en) * 1993-12-24 1995-07-18 Ngk Insulators Ltd Method for backwashing ceramic membrane
JP2001205055A (en) * 2000-01-31 2001-07-31 Daicel Chem Ind Ltd Method for operating membrane separation apparatus and apparatus therefor
JP2001259383A (en) * 2000-03-22 2001-09-25 Ngk Insulators Ltd Membrane backwashing method

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06190251A (en) * 1992-12-28 1994-07-12 Japan Organo Co Ltd Method and apparatus for treatment of water containing turbid component
JPH07178323A (en) * 1993-12-24 1995-07-18 Ngk Insulators Ltd Method for backwashing ceramic membrane
JP2001205055A (en) * 2000-01-31 2001-07-31 Daicel Chem Ind Ltd Method for operating membrane separation apparatus and apparatus therefor
JP2001259383A (en) * 2000-03-22 2001-09-25 Ngk Insulators Ltd Membrane backwashing method

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102515312A (en) * 2011-12-21 2012-06-27 北京大学 Composite ceramic membrane-based filtration method and filtration device for cooling water produced in steel making and continuous casting
JP2018103170A (en) * 2016-12-22 2018-07-05 株式会社クボタ Membrane module operation method and membrane module
JP7541872B2 (en) 2020-08-24 2024-08-29 株式会社クボタ Method for backwashing a membrane separation device
CN112403279A (en) * 2020-09-25 2021-02-26 浙江和达科技股份有限公司 Ceramic membrane filtering device and air-water combined backwashing method thereof

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