JP3608227B2

JP3608227B2 - Membrane separator

Info

Publication number: JP3608227B2
Application number: JP20609594A
Authority: JP
Inventors: 繁樹沢田
Original assignee: Kurita Water Industries Ltd
Current assignee: Kurita Water Industries Ltd
Priority date: 1994-08-09
Filing date: 1994-08-09
Publication date: 2005-01-05
Anticipated expiration: 2020-01-05
Also published as: JPH0852330A

Description

【０００１】
【産業上の利用分野】
この発明は、膜によって内部が原水室と透過室とに仕切られた膜モジュールを有し、原水室に原水を給水し、原水室から膜を透過して透過室に流入した透過水を貯槽に貯え、貯槽から必要個所に配水する膜分離装置に関する。
【０００２】
【従来の技術】
近年、膜分離技術の発達により各種の分野で膜濾過が使用されるようになった。例えば河川水、工業用水、上水を、ＲＯ膜分離するための前処理の凝集、沈殿、濾過に代ってＵＦ膜や、ＭＦ膜で膜濾過を行い、前処理プロセスを簡素化したり、河川水等の水を浄水場で浄化して一般家庭に配水する場合、浄化を膜濾過で行うのに使用されるようになった。このような膜濾過を行う膜分離装置として、本特許出願人は特願平５−２１３０６３号で膜によって内部が原水室と透過室とに仕切られた膜モジュールと、加圧ポンプを有し、原水室に原水を給水する原水給水手段と、原水室から膜を透過して透過室に流入した原水中の透過水を貯槽に取出す採水手段と、貯槽から透過水を必要個所に配水する配水手段と、逆洗ポンプを有し、前記貯槽の透過水を膜モジュールの透過室に注入する逆洗手段と、循環ポンプを有し、透過室の透過水を透過室から抜出して再び透過室に戻す循環手段と、該循環手段に洗浄薬液を注入する薬注手段とを有する装置を提案した。
【０００３】
【発明が解決しようとする課題】
このような膜分離装置で膜濾過運転を行うと、膜の原水室側の膜面に原水に含まれている濁質やコロイドがケーク層を形成すると共に、フミン酸やフルボン酸などの有機性物質（ＴＯＣ成分）が膜面に析出し、ゲル状物質となって強固に膜に付着し、次第に膜の濾過抵抗が増大する。従って、通常は膜分離装置を二系列設置し、その一系列をメインとして運転し、それの原水室側膜面に形成されたケーク層や、ゲル状物質を除去する洗浄を行う際に他の一系列を運転するようにしているため、設備費が嵩むと共に、設置面積も増大する。
【０００４】
【課題を解決するための手段】
上記問題点を解消するために請求項１に記載の発明は、膜によって内部が原水室と透過室とに仕切られた膜モジュールと、加圧ポンプを有し、原水室に原水を給水する原水給水手段と、原水室から膜を透過して透過室に流入した原水中の透過水を貯槽に取出す採水手段と、貯槽から透過水を必要個所に配水する配水手段と、逆洗ポンプを有し、前記貯槽の透過水を洗浄水として膜モジュールの透過室に注入する逆洗手段とを有する膜分離装置において、循環ポンプを有し、前記逆洗手段により洗浄水として透過室に注入された透過水を透過室から抜出して再び透過室に戻す循環手段と、薬注ポンプを有し、該循環手段に洗浄薬液を注入する薬注手段を設け、前記貯槽の容量を、膜モジュールの洗浄に使用する透過水の使用水量と、その洗浄時間内に透過水を必要個所に配水しなければならない透過水の必要配水量との合計、又はそれ以上にし、且つ貯槽にはレベルスイッチを設け、このレベルスイッチは、貯槽内の透過水の水量が、膜モジュールの洗浄に使用する透過水の使用水量と、その洗浄時間内に透過水を配水しなければならない透過水の必要給水量との合計、又はそれ以上になるとこれを検出し、前記加圧ポンプ、逆洗ポンプ、循環ポンプ、薬注ポンプに指令し、原水の給水を停止し、膜の洗浄を開始させる膜分離装置であって、薬注手段により洗浄薬液が注入された循環手段の透過水の洗浄薬液の濃度が所定になったら循環ポンプ、薬注ポンプを停め、逆洗手段の逆洗ポンプを作動させる制御手段を備えたことを特徴とする。
【０００５】
【実施例】
図示の実施例は、前述の先行提案と同じで、河川１から河川水を取水ポンプ２で着水槽３に揚水し、着水槽から河川水を原水槽４を経て加圧ポンプＰ_１で膜モジュール１０に供給し、浄化を行う。膜モジュール１０は膜１１によって内部が原水室１２と、透過室１３とに仕切られ、加圧ポンプＰ_１により河川水（原水）は給水管１４で原水室１２に供給される。原水室に供給された原水のうち膜１１を透過した透過水は透過室１３に流入し、こゝから採水管１５で貯槽１６に導き、浄水場の場合は貯槽１６から一般家庭に配水管１７で配水する。尚、図示の膜分離装置はクロスフロー型であるため、原水室に供給された原水中、膜を透過しなかった濃縮水は原水室の出口管１８、給水循環管１９により再び給水管１４に戻され、給水循環ポンプＰ_２で原水室に供給されて循環する。
【０００６】
膜モジュールの膜１１の、原水室側膜面に形成される前述のケーク層や、付着するゲル状物質を洗浄して除去するため、原水室の出口管１８には洗浄廃水の排出管２０を接続し、給水循環管１９には弁Ｖ_１、排出管２０には弁Ｖ_２を設け、原水室から出口管１８に出るのが濃縮水の場合はＶ_１を開、Ｖ_２を閉にし、洗浄廃水の場合はＶ_１を閉、Ｖ_２は開にする。又、貯槽に貯えた透過水を洗浄水として透過室１３に加圧注入し、膜濾過のときとは逆に洗浄水を膜に透過させるため、貯槽と採水管１５の途中との間に逆洗ポンプＰ_３を有する供給管２１を接続する。更に、採水管１５の途中と透過室１３との間に循環ポンプＰ_４を有する循環管２２を接続し、透過室の透過水（洗浄水）を透過室から抜出して再び透過室に戻し、循環できるようにする。そして、この循環管２２には薬液槽２３の例えば次亜塩素酸ソーダを注入するための薬注ポンプＰ_５を有する薬注管２４を接続する。採水管１５には、供給管２１、及び循環管２２の接続位置よりも下流に弁Ｖ_３を設け、洗浄の際には閉にして洗浄水が貯槽１６に流入するのを防止する。又、循環管２２の透過室１３に接続する端部には弁Ｖ_４を設ける。
【０００７】
洗浄を行うには、弁Ｖ_１，Ｖ_３を閉、弁Ｖ_２を開、弁Ｖ_４を閉に保ち、ポンプＰ_１，Ｐ_２を停め、先ず逆洗ポンプＰ_３を運転し、貯槽内の透過水を洗浄水にして供給管２１、採水管１５から透過室１３に圧入する。弁Ｖ_３，Ｖ_４が閉、循環ポンプＰ_４は停止しているので透過室に圧入された洗浄水は膜１１を膜濾過の際とは逆方向に透過し、原水室の膜面に形成されたケーク層を剥離しながら原水室に流入し、剥れたケーク層を伴って排出管２０から排出する。尚、少なくともポンプＰ_２の吐出側にチャッキ弁（図示せず）を設け、原水槽４側への逆流を防止する。このケーク層の剥離を約１分行ったら、逆洗ポンプＰ_３の運転を停め、弁Ｖ_４を開にし、循環ポンプＰ_４、薬注ポンプＰ_５を運転する。これによって透過室を満たして残っている洗浄水は循環管２２、採水管１５を通って透過室に循環し、この循環する洗浄水に薬液槽２３の次亜塩素酸ソーダが添加される。循環する洗浄水中の次亜塩素酸ソーダの濃度が所定になったら、循環ポンプ、薬注ポンプを停め、弁Ｖ_４を閉にし、逆洗ポンプＰ_３を運転して貯槽内の透過水を透過室に圧入し、透過室中の次亜塩素酸ソーダを含む洗浄水を膜１１に膜濾過の際とは逆方向に透過させ、膜面に強固に付着したゲル状物質に次亜塩素酸ソーダを接触させてゲル状物質を膜面から除去し、排出管２０から排出する。こうして次亜塩素酸ソーダを含む洗浄水がすべて膜を透過して原水室から排出管２０に排出され、原水室及び透過室が透過水で満ちたら逆洗ポンプの運転を停め、弁Ｖ_２を閉、弁Ｖ_１，Ｖ_３を開にし、加圧ポンプＰ_１、給水循環ポンプＰ_２を運転し、膜濾過を再開する。ゲル状物質を除去する薬液洗浄の所要時間は約３０分から１時間である。
【０００８】
従来は、膜１１の原水室側膜面にケーク層、ゲル状物質が付着し、原水が膜を透過する透過流速が低下する都度、上記洗浄を行い、その洗浄を行っている間は予備の膜分離装置で膜濾過を行って貯槽に透過水を補給し、一般家庭などへの配水に支障が生じるのを防いでいたのである。
【０００９】
本発明は貯槽１６の容量を、前述したケーク層の剥離、ゲル状物質の除去のために洗浄水として使用する透過水の使用水量と、その洗浄時間内に透過水を一般家庭などに配水しなければならない必要配水量との合計、又はそれ以上にする。この場合、必要配水量は、洗浄の所要時間が１時間であるときは、１時間よりも多い例えば２時間分の配水量にすることが好ましい。そして、貯槽１６にはレベルスイッチ２５を設け、貯水槽内の透過水の水量が上記洗浄に使用する透過水の使用水量と、洗浄時間内の必要配水量との合計、又はそれ以上になるとレベルスイッチ２５は水位でそれを検出して制御器２６に出力し、制御器２６は前述のポンプＰ_１，Ｐ_２，Ｐ_３，Ｐ_４，Ｐ_５、及び弁Ｖ_１，Ｖ_２，Ｖ_３，Ｖ_４をシーケンス制御し、原水の給水を停めて膜濾過を停止し、ケーク層の剥離、ゲル状物質の除去の洗浄を自動的に行わせ、洗浄が終ると膜濾過を再開させるのである。
【００１０】
膜濾過の停止、ケーク層の剥離、ゲル状物質の除去、膜濾過の再開のためのポンプや弁の制御の態様は前述した通りである。
【００１２】
【発明の効果】
この発明によれば、貯槽内の透過水の水量が、洗浄に使用する透過水の使用水量と、洗浄時間内の必要配水量の合計、又はそれ以上になり、洗浄を行っても一般家庭などへの配水に支障が無くなったら洗浄を行うので、膜分離装置は一系列設置するだけで済み、二系列設置する場合に較べて設備費は大幅に低減すると共に、設置面積も少なくて済む。更に、貯槽内の透過水の水量が、洗浄に使用する透過水の使用水量と、洗浄時間内の必要配水量の合計、又はそれ以上になると洗浄が開始する。これによって膜濾過の開始から洗浄の開始までの膜濾過運転時間は、膜の原水側膜面にケーク層が形成され、且つゲル状物質が付着して膜の透過流速が低下したら洗浄を開始する従来の場合に較べて可成り短くなる。従って、膜の原水側膜面に形成されるケーク層や、付着するゲル状物質が少ないうちに洗浄を行うので洗浄に使用する透過水の使用量、及び薬液の使用量は節減できると共に、洗浄の所要時間も短縮し、それでいて充分な洗浄効果をあげることができる。
【図面の簡単な説明】
【図１】本発明の膜分離装置の一実施例の系統図である。
【符号の説明】
１河川
２取水ポンプ
３着水槽
４原水槽
１０膜モジュール
１１膜
１２原水室
１３透過室
１４給水管
１５採水管
１６貯槽
１７配水管
１８出口管
１９給水循環管
２０洗浄廃水の排出管
２１逆洗水の供給管
２２循環管
２３薬液槽
２４薬注管
２５レベルスイッチ
２６制御器
Ｐ_１加圧ポンプ
Ｐ_２給水循環ポンプ
Ｐ_３逆洗ポンプ
Ｐ_４循環ポンプ
Ｐ_５薬注ポンプ
Ｖ_１弁
Ｖ_２弁
Ｖ_３弁
Ｖ_４弁[0001]
[Industrial application fields]
This invention has a membrane module whose interior is divided into a raw water chamber and a permeation chamber by a membrane, feeds raw water into the raw water chamber, and permeate that has permeated the membrane from the raw water chamber and flowed into the permeation chamber into the storage tank. The present invention relates to a membrane separation device that stores and distributes water from a storage tank to necessary places.
[0002]
[Prior art]
In recent years, membrane filtration has been used in various fields due to the development of membrane separation technology. For example, instead of agglomeration, precipitation, and filtration of pretreatment for separating RO water from river water, industrial water, and clean water, membrane filtration is performed with a UF membrane or MF membrane to simplify the pretreatment process, When water such as water is purified at a water purification plant and distributed to ordinary households, it has come to be used for purification by membrane filtration. As a membrane separation apparatus for performing such membrane filtration, the present applicant has a membrane module whose interior is divided into a raw water chamber and a permeation chamber by a membrane in Japanese Patent Application No. 5-213063, and a pressure pump. Raw water supply means for supplying raw water to the raw water room, water sampling means for extracting the permeated water in the raw water that has passed through the membrane from the raw water room and flowed into the permeation chamber, and water distribution that distributes the permeated water from the storage tank to the necessary locations And a backwashing means having a backwash pump and injecting the permeated water of the storage tank into the permeation chamber of the membrane module, and having a circulation pump, extracting the permeated water of the permeation chamber from the permeation chamber and returning to the permeation chamber again. An apparatus having a circulation means for returning and a medicine injection means for injecting a cleaning chemical into the circulation means has been proposed.
[0003]
[Problems to be solved by the invention]
When membrane filtration operation is performed with such a membrane separator, turbidity and colloids contained in the raw water form a cake layer on the membrane surface on the raw water chamber side of the membrane, and organic substances such as humic acid and fulvic acid are used. The substance (TOC component) precipitates on the membrane surface and becomes a gel-like substance and adheres firmly to the membrane, gradually increasing the filtration resistance of the membrane. Therefore, normally, two series of membrane separation devices are installed, and the one series is operated as the main, and the cake layer formed on the raw water chamber side membrane surface and other washings when removing the gel-like substance are performed. Since one line is operated, the equipment cost increases and the installation area also increases.
[0004]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the invention according to claim 1 is a raw water having a membrane module that is partitioned into a raw water chamber and a permeation chamber by a membrane and a pressure pump, and supplying the raw water to the raw water chamber. There are water supply means, water collection means for extracting the permeated water in the raw water that has passed through the membrane from the raw water chamber and flowed into the permeation chamber, a water distribution means for distributing the permeated water from the storage tank to the required location, and a backwash pump. And a backwashing means for injecting the permeated water of the storage tank into the permeation chamber of the membrane module as washing water, and having a circulation pump and being injected into the permeation chamber as washing water by the backwashing means A circulation means for extracting permeate water from the permeation chamber and returning it to the permeation chamber and a chemical injection pump for injecting a cleaning chemical into the circulation means are provided, and the capacity of the storage tank is used for cleaning the membrane module. The amount of permeated water used and when cleaning it The permeated water must be distributed to the required locations within the sum of the permeated water required, or more, and a level switch is provided in the storage tank. The permeated water used for cleaning the membrane module and the required amount of permeated water to which permeated water must be distributed within the cleaning time are detected or detected when the sum is exceeded. This is a membrane separation device that commands the pressure pump, backwash pump, circulation pump, and chemical injection pump, stops the supply of raw water, and starts cleaning the membrane. A control means for stopping the circulation pump and the chemical injection pump and operating the backwash pump of the backwash means when the concentration of the cleaning chemical solution for permeated water reaches a predetermined value is provided.
[0005]
【Example】
The embodiment shown in the figure is the same as the above-mentioned prior proposal. River water is taken from the river 1 to the landing tank 3 by the water pump 2, and the river water from the landing tank is passed through the raw water tank 4 to the membrane module by the pressure pump P _1. 10 to be purified. The inside of the membrane module 10 is partitioned into a raw water chamber 12 and a permeation chamber 13 by a membrane 11, and river water (raw water) is supplied to the raw water chamber 12 through a water supply pipe 14 by a pressure pump P ₁ . Of the raw water supplied to the raw water chamber, the permeated water that has permeated through the membrane 11 flows into the permeation chamber 13 and is led from here to a storage tank 16 by a sampling pipe 15. In the case of a water purification plant, a distribution pipe 17 is supplied from the storage tank 16 to a general household. Distribute with water. In addition, since the membrane separation apparatus shown in the figure is of a cross flow type, the concentrated water that has not permeated the membrane in the raw water supplied to the raw water chamber is returned to the water supply pipe 14 again by the outlet pipe 18 and the water supply circulation pipe 19 of the raw water chamber. returned and circulated is supplied to the raw water chamber in the feed water circulating pump P _2.
[0006]
In order to clean and remove the above-mentioned cake layer formed on the membrane surface of the membrane 11 of the membrane module and the adhering gel substance, a discharge pipe 20 for washing waste water is provided at the outlet pipe 18 of the raw water chamber. Connected, the supply water circulation pipe 19 is provided with a valve V ₁ and the discharge pipe 20 is provided with a valve V _{2. When} concentrated water is discharged from the raw water chamber to the outlet pipe 18, V ₁ is opened, V ₂ is closed, closing the _{V 1} was when the washing waste liquid, _{V 2} is open. Also, the permeated water stored in the storage tank is pressurized and injected into the permeation chamber 13 as washing water, and the washing water is permeated through the membrane, contrary to membrane filtration. connecting the supply pipe 21 having a wash pump _{P 3.} Further, a circulation pipe 22 having a circulation pump P ₄ is connected between the middle of the water sampling pipe 15 and the permeation chamber 13, and the permeated water (wash water) in the permeation chamber is extracted from the permeation chamber and returned to the permeation chamber for circulation. It can be so. Then, a chemical injection pipe 24 having a chemical injection pump P ₅ for injecting, for example, sodium hypochlorite in the chemical tank 23 is connected to the circulation pipe 22. The Tomizukan 15, supply pipe 21, and the valve V ₃ on the downstream than the connecting position of the circulation pipe 22 is provided, at the time of cleaning the washing water in the closed is prevented from flowing into the reservoir 16. A valve V ₄ is provided at the end of the circulation pipe 22 connected to the permeation chamber 13.
[0007]
In order to perform cleaning, the valves V ₁ and V ₃ are closed, the valve V ₂ is opened, the valve V ₄ is kept closed, the pumps P ₁ and P ₂ are stopped, the backwash pump P ₃ is first operated, The permeated water is made into wash water and pressed into the permeation chamber 13 from the supply pipe 21 and the water sampling pipe 15. Since the valves V ₃ and V ₄ are closed and the circulation pump P ₄ is stopped, the washing water press-fitted into the permeation chamber permeates the membrane 11 in the opposite direction to the membrane filtration and forms on the membrane surface of the raw water chamber. The peeled cake layer flows into the raw water chamber while being peeled off, and is discharged from the discharge pipe 20 together with the peeled cake layer. Note that check valve (not shown) provided on at least the discharge side of the pump P _2, to prevent backflow into the raw water tank 4 side. When subjected to a peeling of the cake layer about 1 minute, stop the operation of the backwashing pump P _3, the valve V ₄ is opened, the circulating pump P _4, operating the chemical feed pump P _5. As a result, the washing water remaining in the permeation chamber is circulated to the permeation chamber through the circulation pipe 22 and the water sampling pipe 15, and sodium hypochlorite in the chemical tank 23 is added to the circulation washing water. Transmission When the concentration of sodium hypochlorite in the wash water circulating becomes a predetermined, circulating pump, stop the dosing pump, the valve V ₄ closed, the permeate storage tank by operating the backwashing pump P ₃ It is press-fitted into the chamber, and the washing water containing sodium hypochlorite in the permeation chamber is permeated through the membrane 11 in the opposite direction to the membrane filtration, so that sodium hypochlorite is applied to the gel substance firmly adhered to the membrane surface. To remove the gel-like substance from the membrane surface and discharge from the discharge pipe 20. Thus is discharged to the discharge pipe 20 from the transmission to the raw water chamber cleaning water are all film containing sodium hypochlorite, raw chamber and the transmission chamber parked operation of backwash pump Once filled with permeate, valve V ₂ The valves V ₁ and V ₃ are closed, the pressurization pump P ₁ and the feed water circulation pump P ₂ are operated, and membrane filtration is resumed. The time required for the chemical cleaning to remove the gel substance is about 30 minutes to 1 hour.
[0008]
Conventionally, when the cake layer or gel-like substance adheres to the membrane surface of the membrane 11 of the membrane 11 and the permeation flow rate through which the membrane water permeates the membrane decreases, the above-mentioned washing is performed. Membrane filtration was performed with a membrane separator to replenish the permeated water in the storage tank, thereby preventing troubles in water distribution to ordinary households.
[0009]
The present invention distributes the capacity of the storage tank 16 to the general household etc. within the cleaning time and the amount of permeated water used as cleaning water for the above-mentioned peeling of the cake layer and removal of the gel substance. Make it the sum or more of the required water distribution. In this case, when the time required for washing is 1 hour, the required water distribution amount is preferably set to a water distribution amount that is greater than 1 hour, for example, 2 hours. The storage tank 16 is provided with a level switch 25. When the amount of permeated water in the water tank is equal to or greater than the sum of the amount of permeated water used for the cleaning and the required water distribution amount within the cleaning time, the level is reached. The switch 25 detects the water level and outputs it to the controller 26. The controller 26 outputs the pumps P ₁ , P ₂ , P ₃ , P ₄ , P ₅ and the valves V ₁ , V ₂ , V ₃ , the V ₄ and sequence control, the membrane filtration is stopped parked the water supply of the raw water, separation of the cake layer, washing removal of the gel-like material was automatically performed, than is resuming the end the membrane filtration washing.
[0010]
The mode of controlling the pump and valve for stopping the membrane filtration, peeling the cake layer, removing the gel-like substance, and restarting the membrane filtration is as described above.
[0012]
【The invention's effect】
According to this invention, the amount of permeated water in the storage tank becomes the sum of the amount of permeated water used for cleaning and the required amount of water distribution within the cleaning time, or more, and even if cleaning is performed, ordinary households, etc. Cleaning is performed when there is no problem in water distribution to the water supply, so it is only necessary to install the membrane separation apparatus in one line, and the equipment cost can be greatly reduced and the installation area can be reduced as compared with the case of installing in two lines. Furthermore, when the amount of permeated water in the storage tank becomes the sum of the amount of permeated water used for cleaning and the required amount of water distribution within the cleaning time, or more, the cleaning starts. As a result, the membrane filtration operation time from the start of membrane filtration to the start of washing starts washing when a cake layer is formed on the membrane surface of the raw water side of the membrane, and the permeation flow rate of the membrane decreases due to adhesion of gel substances. Compared to the conventional case, it is considerably shorter. Therefore, the cake layer formed on the membrane surface of the raw water side of the membrane, and the amount of permeated water used for washing and the amount of chemical used can be reduced because washing is performed while the amount of attached gel-like substance is small. The time required for this is also shortened, and still a sufficient cleaning effect can be obtained.
[Brief description of the drawings]
FIG. 1 is a system diagram of an embodiment of a membrane separation apparatus of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 River 2 Water intake pump 3 Landing tank 4 Raw water tank 10 Membrane module 11 Membrane 12 Raw water chamber 13 Permeation chamber 14 Water supply pipe 15 Water sampling pipe 16 Storage tank 17 Water distribution pipe 18 Outlet pipe 19 Water supply circulation pipe 20 Washing waste water discharge pipe 21 Backwash water Supply pipe 22 Circulation pipe 23 Chemical solution tank 24 Chemical injection pipe 25 Level switch 26 Controller P ₁ Pressurization pump P ₂ Feed water circulation pump P ₃ Backwash pump P ₄ Circulation pump P ₅ Chemical injection pump V ₁ valve V ₂ valve V ₃ valves V ₄ valves

Claims

膜によって内部が原水室と透過室とに仕切られた膜モジュールと、加圧ポンプを有し、原水室に原水を給水する原水給水手段と、原水室から膜を透過して透過室に流入した原水中の透過水を貯槽に取出す採水手段と、貯槽から透過水を必要個所に配水する配水手段と、逆洗ポンプを有し、前記貯槽の透過水を洗浄水として膜モジュールの透過室に注入する逆洗手段とを有する膜分離装置において、循環ポンプを有し、前記逆洗手段により洗浄水として透過室に注入された透過水を透過室から抜出して再び透過室に戻す循環手段と、薬注ポンプを有し、該循環手段に洗浄薬液を注入する薬注手段を設け、前記貯槽の容量を、膜モジュールの洗浄に使用する透過水の使用水量と、その洗浄時間内に透過水を必要個所に配水しなければならない透過水の必要配水量との合計、又はそれ以上にし、且つ貯槽にはレベルスイッチを設け、このレベルスイッチは、貯槽内の透過水の水量が、膜モジュールの洗浄に使用する透過水の使用水量と、その洗浄時間内に透過水を配水しなければならない透過水の必要給水量との合計、又はそれ以上になるとこれを検出し、前記加圧ポンプ、逆洗ポンプ、循環ポンプ、薬注ポンプに指令し、原水の給水を停止し、膜の洗浄を開始させる膜分離装置であって、
薬注手段により洗浄薬液が注入された循環手段の透過水の洗浄薬液の濃度が所定になったら循環ポンプ、薬注ポンプを停め、逆洗手段の逆洗ポンプを作動させる制御手段を備えたことを特徴とする膜分離装置。The membrane module was internally partitioned into a raw water chamber and a permeation chamber by a membrane, a pressure pump, raw water supply means for supplying raw water to the raw water chamber, and the raw water chamber permeated the membrane and flowed into the permeation chamber Water collection means for extracting permeated water from the raw water into the storage tank, water distribution means for distributing permeated water from the storage tank to the necessary locations, and a backwash pump, and using the permeated water in the storage tank as washing water in the permeation chamber of the membrane module In the membrane separation apparatus having a backwashing means for injecting, a circulation means having a circulation pump, and extracting the permeated water injected into the permeation chamber as wash water by the backwashing means and returning it to the permeation chamber again; A chemical injection pump is provided, and a chemical injection means for injecting a cleaning chemical into the circulation means is provided, and the capacity of the storage tank is determined based on the amount of permeated water used for cleaning the membrane module and the permeated water within the cleaning time. Permeation that has to be distributed to the necessary places And the storage tank is provided with a level switch, and the level switch is configured so that the amount of permeated water in the storage tank is equal to the amount of permeated water used for cleaning the membrane module, When the sum of the permeated water required to distribute the permeated water within the washing time or more than this is detected, this is detected and commanded to the pressurization pump, backwash pump, circulation pump and chemical injection pump. A membrane separation device that stops the supply of raw water and starts washing the membrane,
When the concentration of the cleaning chemical solution of the permeated water of the circulating means into which the cleaning chemical solution was injected by the chemical injection means becomes predetermined, the circulation pump and the chemical injection pump are stopped and the control means for operating the back washing pump of the back washing means is provided. A membrane separator characterized by the above.