JP4583557B2 - Operating method and cleaning method of spiral membrane element and spiral membrane module - Google Patents

Description

【０１５７】
ただし、Ｒは２価の芳香族、脂環族もしくは脂肪族炭化水素基、またはこれらの炭化水素基が２価の有機結合基で結合された２価の有機基を示す。
【０１５８】
好ましくは、下記の構造式（化２）〜（化４）で示されるポリスルホンが用いられる。
【０１５９】
【化２】

【０１６０】
【化３】

【０１６１】
【化４】

【０１６２】
また、ポリスルホンの溶媒としては、Ｎ−メチル−２−ピロリドン、ジメチルホルムアミド、ジメチルアセトアミド、ジメチルスルホキシド等を用いることが好ましい。さらに、非溶媒としては、エチレングリコール、ジエチレングリコール、プロピレングリコール、ポリエチレングリコール、グリセリン等の脂肪族多価アルコール、メタノール、エタノール、イソプロピルアルコール等の低級脂肪族アルコール、メチルエチルケトン等の低級脂肪族ケトンなどを用いることが好ましい。
【０１６３】
溶媒と非溶媒の混合溶媒中の非溶媒の含有量は、得られる混合溶媒が均一である限り特に制限されないが、通常５〜５０重量％、好ましくは２０〜４５重量％である。
【０１６４】
多孔質構造の形成を促進し、または制御するために用いられる膨潤剤としては、塩化リチウム、塩化ナトリウム、硝酸リチウム等の金属塩、ポリエチレングリコール、ポリビニルアルコール、ポリビニルピロリドン、ポリアクリル酸等の水溶性高分子またはその金属塩、ホルムアミド等が用いられる。混合溶媒中の膨潤剤の含有量は、製膜溶液が均一である限り特に制限されないが、通常１〜５０重量％である。
【０１６５】
製膜溶液中のポリスルホンの濃度は、通常１０〜３０重量％が好ましい。３０重量％を超えるときは、得られる多孔質分離膜の透水性が実用性に乏しくなり、１０重量％より少ないときは、得られる多孔質分離膜の機械的強度が乏しくなり、充分な背圧強度を得ることができない。
【０１６６】
次に、上記の製膜溶液を不織布支持体上に製膜する。すなわち、連続製膜装置を使用し、不織布等の支持体シートを順次送り出し、その表面に製膜溶液を塗布する。塗布方法としてはナイフコータやロールコータ等のギャップコータを用いて製膜溶液を不織布支持体上に塗布する。例えば、ロールコータを使用する場合は、２本のロールの間に製膜溶液を溜め、不織布支持体上に製膜溶液を塗布すると同時に不織布の内部に充分含浸させ、その後低湿度雰囲気を通過させ、雰囲気中の微量水分を不織布上に塗布した液膜表面に吸収させ、液膜の表面層にミクロ相分離を起こさせる。その後、凝固水槽に浸漬し、液膜全体を相分離および凝固させ、さらに水洗槽で溶媒を洗浄除去する。これにより、分離膜２が形成される。
【０１６７】
このように、上記の分離膜２は背圧強度が高いため、図１および図６のスパイラル型膜エレメント１に用いた場合に０．０５〜０．３ＭＰａの背圧で逆流洗浄を行っても分離膜２の破損が生じることが防止される。
【０１６８】
【実施例】
以下の実施例１〜３および比較例においては、図７に示す構造を有する限外濾過膜を分離膜２として含むスパイラル型限外濾過膜エレメントを作製し、このスパイラル型限外濾過膜エレメントを備えた図１のスパイラル型膜モジュールを用いて後述する条件で連続通水濾過試験を行った。
【０１６９】
実施例１〜３および比較例に用いるスパイラル型限外濾過膜エレメントの仕様は以下の表１に示す通りである。
【０１７０】
【表１】

【０１７１】
ここで、実施例１〜３および比較例のスパイラル型限外濾過膜エレメントに用いた限外濾過膜は、以下のようにして作製した。
【０１７２】
まずポリスルホン（アモコ社製、Ｐ−３５００）を１６．５重量部、Ｎ−メチル−２ピロリドンを５０重量部、ジエチレングリコールを２４．５重量部およびホルムアミドを１重量部で加熱溶解し、均一な製膜溶液を得た。そして、コータギャップを０．１３ｍｍに調整したロールコータを用いて厚み０．１ｍｍ、密度０．８ｇ／ｃｍ³ のポリエステル製不織布の表面に製膜溶液を含浸塗布した。
【０１７３】
その後、相対湿度が２５％、温度が３０℃の雰囲気（低湿度雰囲気）中を所定の速度で通過させ、ミクロ相分離を生じさせた後、３５℃の凝固水槽中に浸漬して脱溶媒および凝固させ、しかる後、水洗槽で残存溶媒を洗浄除去することにより分離膜２を得た。ここで、実施例１および実施例２の分離膜２は、ミクロ相分離時間（低湿度雰囲気を通過する時間）が４．５秒である。
【０１７４】
上記のようにして作製した限外濾過膜の透水量は１７００Ｌ／ｍ² ・ｈｒであり、背圧強度は０．３ＭＰａであり、平均分子量１００万のポリエチレンオキサイドの阻止率は９９％であった。
【０１７５】
なお、背圧強度は直径４７ｍｍの膜を背圧強度ホルダ（有孔直径２３ｍｍ）にセットし、多孔性補強シート２ａ側より水圧を徐々に加え、透過性膜体２ｂが多孔性補強シート２ａから剥離するか、または透過性膜体２ｂと多孔性補強シート２ａとが同時に破裂するときの圧力で規定される。
【０１７６】
また、ポリエチレンオキサイドの阻止率は、濃度５００ｐｐｍのポリエチレンオキサイド溶液を圧力１ｋｇｆ／ｃｍ² にて透過させ、原液および透過液の濃度から下式により求めた。
【０１７７】
阻止率（％）［１−（透過液濃度／原液濃度）］×１００
次に、このようにして作製した限外濾過膜を備えたスパイラル型膜モジュールの連続通水濾過試験について以下に説明する。なお、この場合の連続通水濾過試験においては原水７として工業用水（ｐＨ６〜８、水温１５〜３０℃）を供給した。
【０１７８】
［実施例１］
実施例１においては、図１のスパイラル型膜モジュールに供給する原水７中に、常時、殺菌作用および汚染物質の除去作用を有する次亜塩素酸ナトリウムを注入して濾過を行った。実施例１におけるスパイラル型膜モジュールの運転条件を以下の表２に示す。
【０１７９】
【表２】

【０１８０】
なお、逆流洗浄時においては、洗浄水２１（図３）として透過水８（図２）を用い、０．１〜０．２ＭＰａの背圧で５６Ｌ／分の流量で洗浄水２１の供給を行った。また、この場合においては、逆流洗浄後に原水３１（図３）をスパイラル型膜モジュールに供給し、スパイラル型限外濾過膜エレメント内部において濾過時の原水７（図２）の供給方向と同方向に原水３１を流した。
【０１８１】
上記のような濾過および洗浄を繰り返し行いながら連続してスパイラル型限外濾過膜エレメントの運転を行った。そして、スパイラル型限外濾過膜エレメントにおける運転時間と膜間差圧との関係を調べた。
【０１８２】
［実施例２］
実施例２においては、図１のスパイラル型膜モジュールの逆流洗浄時に殺菌作用および汚染物質の除去作用を有する次亜塩素酸ナトリウムを洗浄水２１（図３）に注入し、この洗浄水２１（逆洗水）を用いて逆流洗浄を行った。実施例２におけるスパイラル型膜モジュールの運転条件を以下の表３に示す。
【０１８３】
【表３】

【０１８４】
なお、逆流洗浄時においては、洗浄水２１（図３）として透過水８（図２）を用い、０．１〜０．２ＭＰａの背圧で５６Ｌ／分の流量で洗浄水２１の供給を行った。また、この場合においては、逆流洗浄後に原水３１（図３）をスパイラル型膜モジュールに供給し、スパイラル型限外濾過膜エレメント内部において濾過時の原水７（図２）の供給方向と同方向に原水３１を流した。
【０１８５】
上記のような濾過および洗浄を繰り返し行いながら連続してスパイラル型限外濾過膜エレメントの運転を行った。そして、スパイラル型限外濾過膜エレメントにおける運転時間と膜間差圧との関係を調べた。
【０１８６】
［実施例３］
実施例３においては、図１のスパイラル型膜モジュールを５日間連続運転した後、殺菌作用および汚染物質の除去作用を有する次亜塩素酸ナトリウムを注入した洗浄水をスパイラル型膜モジュールに供給してスパイラル型限外濾過膜エレメントの浸漬洗浄を行った。実施例３におけるスパイラル型膜モジュールの運転条件を以下の表４に示す。
【０１８７】
【表４】

【０１８８】
なお、逆流洗浄時においては、洗浄水２１（図３）として透過水８（図２）を用い、０．１〜０．２ＭＰａの背圧で５６Ｌ／分の流量で洗浄水２１の供給を行った。また、この場合においては、逆流洗浄後に原水３１（図３）をスパイラル型膜モジュールに供給し、スパイラル型限外濾過膜エレメント内部において濾過時の原水７（図２）の供給方向と同方向に原水３１を流した。
【０１８９】
また、本例においては、浸漬洗浄時に適宜逆流洗浄用の洗浄水２１に次亜塩素酸ナトリウムを注入し、この次亜塩素酸ナトリウムが注入された洗浄水２１を浸漬洗浄用の洗浄水として用いた。
【０１９０】
上記のような濾過および洗浄を繰り返し行いながら連続してスパイラル型膜モジュールの運転を行った。そして、スパイラル型限外濾過膜エレメントにおける運転時間と膜間差圧との関係を調べた。
【０１９１】
［比較例］
比較例においては、図１のスパイラル型膜モジュールの濾過運転時および洗浄時において薬品注入を一切行わなかった。比較例におけるスパイラル型膜モジュールの運転条件を以下の表５に示す。
【０１９２】
【表５】

【０１９３】
なお、逆流洗浄時においては、洗浄水２１（図３）として透過水８（図２）を用い、０．１〜０．２ＭＰａの背圧で５６Ｌ／分の流量で洗浄水２１の供給を行った。また、この場合においては、逆流洗浄後に原水３１（図３）をスパイラル型膜モジュールに供給し、スパイラル型限外濾過膜エレメント内部において濾過時の原水７（図２）の供給方向と同方向に原水３１を流した。
【０１９４】
上記のような濾過および洗浄を繰り返し行いながら連続してスパイラル型膜モジュールの運転を行った。そして、スパイラル型限外濾過膜エレメントにおける運転時間と膜間差圧との関係を調べた。
【０１９５】
図８は実施例１〜３および比較例におけるスパイラル型膜モジュールの膜間差圧の経時変化を示す図である。
【０１９６】
図８に示すように、原水７中に常時次亜塩素酸ナトリウムを注入した実施例１においては、膜面における微生物の繁殖を抑制することができるとともに膜面への汚染物質の付着を防止することができる。このため、スパイラル型限外濾過膜エレメントの膜間差圧の変化が小さく、スパイラル型膜モジュールにおいて安定した運転を長期間継続して行うことが可能であった。
【０１９７】
また、逆流洗浄時の洗浄水２１に次亜塩素酸ナトリウムを注入した実施例２においては、一定間隔でしか膜面が次亜塩素酸ナトリウムと接触しないため、実施例１に比べて効果が低くなる。しかしながら、この場合においてもスパイラル型限外濾過膜エレメントにおいて十分に膜間差圧の上昇を抑制することが可能であり、膜間差圧の変化が小さくすることができる。したがって、スパイラル型膜モジュールにおいて、安定した運転を長期間継続して行うことが可能であった。
【０１９８】
一方、実施例３においては、濾過時および逆流洗浄時に薬品注入を行わないため運転時間の経過とともに膜間差圧は上昇する。しかしながら、この場合においては、膜間差圧の上昇に伴って次亜塩素酸ナトリウムを含む洗浄水で浸漬洗浄を行うため、膜間差圧の上昇を抑制することが可能である。したがって、スパイラル型膜モジュールにおいて、安定した運転を長期間継続して行うことが可能であった。
【０１９９】
これに対して、濾過時および洗浄時に薬品の注入を全く行わない比較例においては、運転時間の経過に伴い急激な膜間差圧の上昇が生じるため、連続運転継続が不可能であった。
【図面の簡単な説明】
【図１】本発明の一実施の形態におけるスパイラル型膜モジュールの一例を示す模式的な図である。
【図２】本発明に係るスパイラル型膜モジュールの運転方法の一例を示す模式的断面図である。
【図３】本発明に係るスパイラル型膜モジュールの運転方法の一例を示す模式的断面図である。
【図４】本発明に係るスパイラル型膜モジュールの運転方法の他の例を示す模式的断面図である。
【図５】図１のスパイラル型膜モジュールに用いられるスパイラル型膜エレメントの一部切欠き斜視図である。
【図６】本発明に係るスパイラル型膜モジュールの運転方法のさらに他の例を示す模式的断面図である。
【図７】図５のスパイラル型膜エレメントに用いられる分離膜の断面図である。
【図８】実施例１〜３および比較例のスパイラル型膜モジュールの膜間差圧の経時変化を示す図である。
【符号の説明】
１ スパイラル型膜エレメント
２ 分離膜
３ 透過水スペーサ
４ 封筒状膜
５ 集水管
６ 原水スペーサ
７，３１ 原水
８ 透過水
１０，１００ 圧力容器
１３，１３０ 原水入口
１４，１４０ 透過水出口
１５，１３１ 原水出口
２１ 洗浄水[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of operating and cleaning a spiral membrane element and a spiral membrane module used in membrane separation devices such as reverse osmosis membrane separation devices, ultrafiltration membrane separation devices, and microfiltration membrane separation devices.
[0002]
[Prior art]
In recent years, the application of membrane separation technology to water purification and wastewater treatment has expanded, and membrane separation technology has been applied to liquid quality, which has been difficult in the past. In particular, there is a strong demand for the recovery and reuse of industrial wastewater using membrane separation technology.
[0003]
As a form of the membrane element used for such membrane separation, a hollow fiber membrane element is often used from the viewpoint of membrane area per unit volume (volume efficiency). However, the hollow fiber membrane element has a drawback that the membrane is easily broken, and when the membrane is broken, the raw water is mixed with the permeated water and the separation performance is lowered.
[0004]
Therefore, it has been proposed to apply a spiral membrane element instead of the hollow fiber membrane element. Similar to the hollow fiber membrane element, this spiral membrane element has the advantage that the membrane area per unit volume can be increased, the separation performance can be maintained, and the reliability is high.
[0005]
[Problems to be solved by the invention]
Since wastewater contains many suspended substances, colloidal substances, or dissolved substances, when membrane separation is performed on such wastewater, these suspended substances, colloidal substances, or dissolved substances are contaminated on the membrane surface. It accumulates and causes a decrease in the water transmission rate. In particular, when the total amount is filtered, contaminants are likely to be deposited on the membrane surface, the water permeation rate is significantly reduced, and it is difficult to continue a stable filtration operation.
[0006]
In order to prevent the accumulation of contaminants on the membrane surface, cross flow filtration is performed.
In this cross flow filtration, the raw water is allowed to flow parallel to the membrane surface, thereby preventing the deposition of contaminants on the membrane surface using the shearing force generated at the interface between the membrane surface and the fluid. In such cross-flow filtration, it is necessary to obtain a sufficient film surface linear velocity to prevent the deposition of contaminants on the film surface. For this purpose, a sufficient flow rate of raw water is made parallel to the film surface. Need to flow. However, when the flow rate of the raw water flowing parallel to the membrane surface is increased, the recovery rate per spiral membrane element is lowered, and the pump for supplying the raw water becomes large, resulting in a very high system cost.
[0007]
On the other hand, contaminants deposited on the film surface are also removed by backwashing. Backwashing is generally performed for hollow fiber membrane elements.
[0008]
For example, Japanese Patent Publication No. 6-98276 proposes application of backwashing to a spiral membrane element. However, since the separation membrane of the conventional spiral membrane element has low back pressure strength, the separation membrane may be damaged when back pressure is applied to the separation membrane during backflow cleaning. Therefore, according to the above publication, the spiral membrane element is 0.1 to 0.5 kg / cm. ² It is considered preferable to perform back-flow cleaning with a back pressure as low as (0.01 to 0.05 MPa).
[0009]
However, according to the inventors' experiment, when backwashing is performed with such a back pressure in a spiral membrane element, it is difficult to sufficiently remove contaminants, and a high permeation flux is obtained over a long period of time. It could not be maintained.
[0010]
On the other hand, the present inventor has disclosed a back pressure strength of 2 kgf / cm in JP-A-10-225626. ² The structure and manufacturing method of the above separation membrane are proposed. However, when a spiral membrane element is manufactured using a separation membrane having such back pressure strength, what back pressure can actually be used for backwashing, and what range It has not been fully verified whether a high permeation flux can be maintained over a long period of time when backwashing is performed with a back pressure of. Furthermore, the operation method of the spiral membrane element having the separation membrane having a high back pressure strength as described above and the operation method of the spiral membrane module provided with such a spiral membrane element have not been verified.
[0011]
Even when such a separation membrane with high back pressure strength is used, if the optimum washing conditions and washing method are applied and the filtration operation is not performed by the optimum operation method, the spiral membrane element and the spiral membrane module are long. A stable filtration operation cannot be continued without causing a decrease in permeation flux over a period of time.
[0012]
An object of the present invention is to provide an operation method and a cleaning method of a spiral membrane element and a spiral membrane module capable of performing a stable filtration operation at a low cost while maintaining a high permeation flux over a long period of time. .
[0013]
[Means for Solving the Problems and Effects of the Invention]
The operation method of the spiral membrane element according to the first invention is such that a bag-like separation membrane is wound around the outer peripheral surface of a perforated hollow tube. And having first and second ends , A method of operating a spiral membrane element capable of backwashing with a back pressure of higher than 0.05 MPa and lower than 0.3 MPa. First end And the permeate is taken out from at least one open end of the perforated hollow tube, and the cleaning solution is introduced from at least one open end of the perforated hollow tube at the time of back-flow cleaning. At least one of the first and second ends The separation membrane is backwashed with a back pressure higher than 0.05 MPa and lower than 0.3 MPa by discharging the cleaning liquid from the back of the spiral membrane element before backwashing, during backwashing or after backwashing. Second end Introduce a stock solution containing chemicals that have a pollutant peeling or bactericidal action from the flow of the stock solution in the spiral membrane element in the reverse direction of the filtration operation and First end Is derived from
[0014]
In the operation method of the spiral membrane element according to the present invention, the spiral membrane element is First The stock solution is supplied from the end, and the permeate is taken out from at least one open end of the perforated hollow tube. At the time of backwashing, cleaning liquid is introduced from at least one open end of the perforated hollow tube. The cleaning liquid is led out from the outer peripheral surface of the perforated hollow tube to the inside of the bag-shaped separation membrane, and permeates through the separation membrane in the direction opposite to that during the filtration operation. At least one of the first and second ends As a result, the separation membrane is back-washed with a back pressure higher than 0.05 MPa and lower than 0.3 MPa, and contaminants deposited on the membrane surface of the separation membrane are peeled off from the separation membrane. In this case, a necessary amount of cleaning liquid can be flowed in a short time. Also, before the backwashing, during backwashing or after backwashing, the spiral membrane element Second A stock solution containing a chemical having a pollutant removing action or a bactericidal action is introduced from the end, and the stock solution flows in the spiral membrane element in the direction opposite to that during the filtration operation. First Derived from the end.
[0015]
Thereby, Contaminants deposited on the membrane surface of the separation membrane can be effectively removed. As a result, it is possible to perform a stable filtration operation while maintaining a high permeation flux over a long period of time.
[0016]
Further, in the above method, by supplying a stock solution into which a chemical having a pollutant peeling action is injected to the spiral membrane element, it is possible to suppress the contamination from adhering to at least the membrane surface of the spiral membrane element. Is possible.
[0017]
Further, by supplying a stock solution into which a chemical having a bactericidal action is injected to the spiral membrane element, it is possible to suppress the propagation of germs such as microorganisms on the membrane surface of the spiral membrane element.
[0018]
From the above, the spiral membrane element can be operated stably for a long time.
[0019]
The chemical may be sodium hypochlorite, chloramine, hydrogen peroxide, peracetic acid or ozone. Since these chemicals have the action of decomposing, dissolving, and peeling off contaminants, it is possible to suppress the contaminants from adhering to the membrane surface of the spiral membrane element. Moreover, since it has a bactericidal action, it is possible to suppress the propagation of germs on the membrane surface.
[0020]
Also, Contains medicine The stock solution may contain a flocculant. In this case, since the contaminant contained in the stock solution is aggregated by the flocculant, even if it is a contaminant that passes through the membrane without the flocculant, it is likely to be captured on the film surface by the aggregating action. Therefore, highly accurate filtration can be performed. The contaminant trapped on the membrane surface in this way can be discharged out of the spiral membrane element by back-flow cleaning with a high back pressure higher than 0.05 MPa and lower than 0.3 MPa.
[0021]
Further, at the time of back-flow cleaning, a cleaning liquid containing a chemical having a pollutant removing action or a bactericidal action is introduced from at least one open end of the perforated hollow tube, and the cleaning liquid derived from the outer peripheral surface of the perforated hollow tube is spiral Of the membrane element At least one of the first and second ends The separation membrane may be backwashed with a back pressure of higher than 0.05 MPa and lower than 0.3 MPa by discharging from the vacuum chamber.
[0022]
When the cleaning liquid is introduced from at least one open end of the perforated hollow tube, the cleaning liquid derived from the outer peripheral surface of the perforated hollow tube permeates the separation membrane and flows along the axial direction inside the spiral membrane element. Of spiral membrane element At least one of the first and second ends Discharged from. Thereby, contaminants trapped in the membrane surface of the spiral membrane element, particularly in the pores of the membrane, can be removed. This makes it possible to always maintain a constant permeate amount during operation of the spiral membrane element.
[0023]
In particular, in this case, the contaminant attached to the membrane surface of the spiral membrane element is easily removed by the chemical having the contaminant peeling action contained in the cleaning liquid. This makes it possible to effectively clean the spiral membrane element.
[0024]
In addition, it is possible to effectively suppress the propagation of germs such as microorganisms on the membrane surface of the spiral membrane element by the chemical having a bactericidal action contained in the cleaning liquid.
[0025]
From the above, the spiral membrane element can be operated stably for a long time.
[0026]
In this case, a permeate may be used as the cleaning liquid.
During reverse flow cleaning, the spiral membrane element At least one of the first and second ends Alternatively, a cleaning liquid containing a chemical having a pollutant removing action or a sterilizing action may be supplied, and the cleaning liquid containing the chemical may flow in the axial direction in the spiral membrane element. As a result, it is possible to remove contaminants attached to the membrane surface of the spiral membrane element, in particular, contaminants that have formed a cake layer on the membrane surface. This makes it possible to always maintain a constant permeate amount during operation of the spiral membrane element.
[0027]
In particular, in this case, the contaminant attached to the membrane surface of the spiral membrane element is easily removed by the chemical having the contaminant peeling action contained in the cleaning liquid. This makes it possible to effectively clean the spiral membrane element.
[0028]
In addition, it becomes possible to more effectively suppress the propagation of germs such as microorganisms on the membrane surface of the spiral membrane element by the chemical having a bactericidal action contained in the cleaning liquid.
[0029]
From the above, the spiral membrane element can be operated stably for a long time.
[0030]
In this case, a stock solution may be used as the cleaning solution.
The separation membrane may be formed by bonding a permeable membrane body to one surface of the porous sheet material, and the permeable membrane body may be bonded to one surface of the porous sheet material in a throwing state. In such a separation membrane, the bonding between the porous sheet material and the permeable membrane body is strengthened, and the back pressure strength of the separation membrane is improved. Thereby, it is possible to sufficiently perform back-flow cleaning without causing damage to the separation membrane of the spiral membrane element at a back pressure higher than 0.05 MPa and lower than 0.3 MPa.
[0031]
In particular, the back pressure strength of the separation membrane is preferably 0.2 MPa or more. As a result, back-flow cleaning with a high back pressure becomes possible, and membrane separation treatment stable for a long period of time can be performed by sufficiently performing membrane cleaning.
[0032]
In particular, the porous sheet material is preferably made of a woven fabric, a nonwoven fabric, a mesh net, or a foamed sintered sheet made of a synthetic resin.
[0033]
Further, the porous sheet material has a thickness of 0.08 mm or more and 0.15 mm or less and a density of 0.5 g / cm. ^Three 0.8 g / cm or more ^Three It is preferable to consist of the following nonwoven fabrics.
[0034]
Thereby, while obtaining the back pressure intensity | strength of 0.2 Mpa or more, the increase of a permeation | transmission resistance and peeling of a permeable membrane body can be prevented, ensuring the intensity | strength as a reinforcement sheet.
[0035]
The spiral membrane element cleaning method according to the second invention is such that a bag-shaped separation membrane is wound around the outer peripheral surface of a perforated hollow tube. And having first and second ends , A spiral membrane element cleaning method capable of backwashing with a back pressure of higher than 0.05 MPa and lower than 0.3 MPa, wherein a cleaning liquid is introduced from at least one open end of the perforated hollow tube during backwashing. Of spiral type membrane element At least one of the first and second ends The separation membrane is backwashed at a back pressure higher than 0.05 MPa and lower than 0.3 MPa by discharging from the spiral membrane element before backwashing, during backwashing or after backwashing. Second end Introduce a stock solution containing chemicals that have a pollutant peeling or bactericidal action from the flow of the stock solution in the spiral membrane element in the reverse direction of the filtration operation and First end Is derived from
[0036]
In the method for cleaning a spiral membrane element according to the present invention, the cleaning liquid introduced from at least one open end of the perforated hollow tube is removed from the outer peripheral surface of the perforated hollow tube during backflow cleaning. The inside of the spiral membrane element that is led to the inside and permeates through the separation membrane in the direction opposite to that during filtration. At least one of the first and second ends The separation membrane is backwashed with a back pressure higher than 0.05 MPa and lower than 0.3 MPa by being discharged from the tank. Thereby, contaminants deposited on the membrane surface of the separation membrane, particularly contaminants clogged in the pores of the separation membrane are peeled off from the separation membrane. In this case, a necessary amount of cleaning liquid can be flowed in a short time. Also, before the backwashing, during backwashing or after backwashing, the spiral membrane element Second A stock solution containing a chemical having a pollutant removing action or a bactericidal action is introduced from the end, and the stock solution flows in the spiral membrane element in the direction opposite to that during the filtration operation. First Derived from the end.
[0037]
Thereby, Contaminants deposited on the membrane surface of the separation membrane can be effectively removed. As a result, it is possible to perform a stable filtration operation while maintaining a high permeation flux over a long period of time.
[0038]
Furthermore, in this case, since the cleaning liquid contains a chemical having a contaminant peeling action, contaminants attached to the membrane surface of the spiral membrane element, in particular, contaminants clogged in the pores of the membrane are easily removed. Become. This makes it possible to effectively clean the spiral membrane element.
[0039]
In addition, when the cleaning liquid contains a chemical having a bactericidal action, it is possible to effectively suppress the propagation of germs such as microorganisms on the membrane surface of the spiral membrane element.
[0040]
From the above, the spiral membrane element can be operated stably for a long time.
[0041]
According to a third aspect of the present invention, there is provided a method for cleaning a spiral membrane element in which a bag-shaped separation membrane is wound around the outer peripheral surface of a perforated hollow tube. And having first and second ends , A spiral membrane element cleaning method capable of backwashing with a back pressure of higher than 0.05 MPa and lower than 0.3 MPa, wherein a cleaning liquid is introduced from at least one open end of the perforated hollow tube during backwashing. Of spiral type membrane element At least one of the first and second ends The separation membrane is backwashed at a back pressure of higher than 0.05 MPa and lower than 0.3 MPa by draining the cleaning liquid from the back of the spiral membrane element before backwashing, during backwashing or after backwashing. First end A cleaning liquid containing chemicals having a pollutant removing action or a bactericidal action is introduced from the flow of the cleaning liquid containing chemicals in the spiral type membrane element in the same direction as during filtration operation, and the spiral type membrane element Second end Derived from Operation Of spiral membrane element Second end A cleaning liquid containing chemicals having a pollutant removing action or a sterilizing action is introduced from the inside, and the cleaning liquid containing chemicals flows in the spiral type membrane element in the reverse direction of the filtration operation, and the spiral type membrane element First end Derived from Are performed in order. Is.
[0042]
In the method for cleaning a spiral membrane element according to the present invention, During backwashing, Since the separation membrane of the spiral membrane element can be backwashed with a back pressure higher than 0.05 MPa and lower than 0.3 MPa, a necessary amount of cleaning liquid can be flowed in a short time. Thereby, contaminants deposited on the membrane surface of the separation membrane can be effectively removed. As a result, it is possible to perform a stable filtration operation while maintaining a high permeation flux over a long period of time.
[0043]
Further, in the above method, the spiral membrane element is not cleaned before, during or after the backwashing. First A cleaning liquid containing a chemical having a pollutant removing action or a sterilizing action is introduced from the end, and the cleaning liquid containing the chemical flows in the spiral type membrane element in the same direction as the filtration operation, and the spiral type membrane element Second Derived from the end Operation Of spiral membrane element Second A cleaning liquid containing chemicals having a pollutant removing action or a sterilizing action is introduced from the end, and the cleaning liquid containing chemicals flows in the spiral type membrane element in the direction opposite to that during the filtration operation. First Derived from the end Operations are performed in order . As a result, it is possible to remove contaminants attached to the membrane surface of the spiral membrane element, in particular, contaminants that have formed a cake layer on the membrane surface. This makes it possible to always maintain a constant permeate amount during operation of the spiral membrane element.
[0044]
In particular, in this case, the contaminants attached to the membrane surface of the spiral membrane element can be easily removed by including the chemical having the contaminant peeling action in the cleaning liquid. This makes it possible to effectively clean the spiral membrane element.
[0045]
In addition, when the cleaning liquid contains a chemical having a bactericidal action, it is possible to effectively suppress the propagation of germs such as microorganisms on the membrane surface of the spiral membrane element.
[0046]
From the above, the spiral membrane element can be operated stably for a long time.
[0047]
In this case, a stock solution may be used as the cleaning solution.
In the method for cleaning a spiral membrane element according to the second and third inventions, in parallel with the backflow cleaning by introducing a cleaning liquid containing a chemical from at least one open end of the perforated hollow tube, Regular spiral membrane element At least one of the first and second ends A cleaning liquid containing chemicals may be supplied. In this case, it is possible to simultaneously and effectively remove the contaminants clogged in the pores of the membrane and the contaminants having a cake layer formed on the membrane surface.
[0048]
Further, the spiral membrane element may be immersed in a cleaning liquid containing chemicals.
In this case, a cleaning liquid containing a chemical is introduced into the spiral membrane element from the perforated hollow tube, and the spiral type membrane element is immersed in the cleaning liquid for a predetermined time. For example, in a spiral type membrane module in which a spiral type membrane element is loaded in a pressure vessel, the spiral type membrane element is immersed by filling the inside of the pressure vessel with a cleaning liquid. Thereafter, the cleaning liquid is discharged out of the system. By such immersion, contaminants attached to the membrane surface of the spiral membrane element are easily removed and can be easily cleaned. For this reason, it becomes possible to perform cleaning more effectively. In addition, it is possible to more effectively suppress the propagation of germs such as microorganisms on the membrane surface of the spiral membrane element.
[0049]
From the above, the spiral membrane element can be operated stably for a long time.
[0050]
The chemical may be sodium hypochlorite, chloramine, sulfuric acid, hydrochloric acid, nitric acid, sodium hydroxide, peracetic acid, isopropyl alcohol, oxalic acid or citric acid. Since these chemicals have the action of removing contaminants such as decomposition, dissolution, and peeling of contaminants, it is possible to remove the contaminants attached to the membrane surface of the spiral membrane element and perform cleaning effectively. . Moreover, since it has a bactericidal action, it becomes possible to effectively suppress the propagation of germs on the membrane surface.
[0051]
The operation method of the spiral membrane module according to the fourth invention is such that a bag-shaped separation membrane is wound around the outer peripheral surface of a perforated hollow tube. And having first and second ends Operation of a spiral membrane module in which one or a plurality of spiral membrane elements capable of backwashing with a back pressure higher than 0.05 MPa and lower than 0.3 MPa are accommodated in a pressure vessel having a stock solution inlet and a stock solution outlet A spiral membrane element through a pressure vessel stock inlet during filtration operation. First end And the permeate is taken out from at least one open end of the perforated hollow tube, and the cleaning solution is introduced from at least one open end of the perforated hollow tube at the time of back-flow cleaning. At least one of the first and second ends The separation membrane is backwashed at a back pressure higher than 0.05 MPa and lower than 0.3 MPa by draining the cleaning solution from the pressure vessel, and before the backwashing, during backwashing or after backwashing, the spiral membrane element is passed through the outlet of the pressure vessel. Second end Introduce a stock solution containing chemicals that have a pollutant peeling or bactericidal action from the flow of the stock solution in the spiral membrane element in the reverse direction of the filtration operation and First end And is taken out through the stock solution inlet of the pressure vessel.
[0052]
In the operation method of the spiral membrane module according to the present invention, during the filtration operation, the spiral membrane element First The stock solution is supplied from the end, and the permeate is taken out from at least one open end of the perforated hollow tube. At the time of backflow cleaning, the cleaning liquid introduced from at least one open end of the perforated hollow tube is led out from the outer peripheral surface of the perforated hollow tube to the inside of the bag-shaped separation membrane, and the separation membrane is reversed from that during filtration operation. Of the spiral membrane element At least one of the first and second ends As a result, the separation membrane is back-washed with a back pressure higher than 0.05 MPa and lower than 0.3 MPa, and contaminants deposited on the membrane surface of the separation membrane are peeled off from the separation membrane. In this case, a necessary amount of cleaning liquid can be flowed in a short time. Also, before the backwashing, during backwashing or after backwashing, the spiral membrane element Second A stock solution containing a chemical having a pollutant removing action or a bactericidal action is introduced from the end, and the stock solution flows in the spiral membrane element in the direction opposite to that during the filtration operation. First Derived from the end.
[0053]
Thereby, Contaminants deposited on the membrane surface of the separation membrane can be effectively removed. As a result, it is possible to perform a stable filtration operation while maintaining a high permeation flux over a long period of time.
[0054]
Furthermore, in the above method, a stock solution into which a chemical having a pollutant peeling action is injected is supplied to the spiral membrane element. For this reason, it becomes possible to suppress a contaminant from adhering to the membrane surface of the spiral membrane element.
[0055]
Moreover, since the stock solution into which the chemical | medical agent which has bactericidal action was inject | poured is supplied to a spiral type membrane element, it becomes possible to suppress miscellaneous bacteria, such as microorganisms, on the membrane surface of a spiral type membrane element.
[0056]
From the above, the spiral membrane module can be operated stably for a long time.
[0057]
According to a fifth aspect of the present invention, there is provided a method for cleaning a spiral membrane module, comprising a bag-shaped separation membrane wound around the outer peripheral surface of a perforated hollow tube, and backflow with a back pressure higher than 0.05 MPa and lower than 0.3 MPa. A cleaning method for a spiral membrane module in which one or a plurality of spiral membrane elements capable of cleaning are housed in a pressure vessel having a stock solution inlet and a stock solution outlet, wherein at least one of the perforated hollow tubes is used for backwashing The cleaning solution is introduced from the open end of the spiral membrane element. At least one of the first and second ends The separation membrane is backwashed with a back pressure higher than 0.05 MPa and lower than 0.3 MPa by taking it out of the pressure vessel and passing through the outlet of the pressure vessel before backwashing, during backwashing or after backwashing. Spiral membrane element Second end Introduce a stock solution containing chemicals that have a pollutant peeling or bactericidal action from the flow of the stock solution in the spiral membrane element in the reverse direction of the filtration operation and First end And is taken out through the stock solution inlet of the pressure vessel.
[0058]
According to the method for cleaning a spiral membrane module according to the present invention, the cleaning liquid introduced from at least one open end of the perforated hollow tube is removed from the outer peripheral surface of the perforated hollow tube during backflow cleaning. Of the spiral membrane element through the separation membrane in the reverse direction of filtration. At least one of the first and second ends The separation membrane is backwashed with a back pressure higher than 0.05 MPa and lower than 0.3 MPa by being discharged from the tank. Thereby, the contaminants deposited on the membrane surface of the separation membrane are peeled off from the separation membrane. In this case, a necessary amount of cleaning liquid can be flowed in a short time. Also, before the backwashing, during backwashing or after backwashing, the spiral membrane element Second A stock solution containing a chemical having a pollutant removing action or a bactericidal action is introduced from the end, and the stock solution flows in the spiral membrane element in the direction opposite to that during the filtration operation. First Derived from the end.
[0059]
Thereby, Contaminants deposited on the membrane surface of the separation membrane can be effectively removed. As a result, it is possible to perform a stable filtration operation while maintaining a high permeation flux over a long period of time.
[0060]
In particular, in this case, the contaminants contained in the cleaning liquid and having the ability to remove contaminants can easily remove contaminants attached to the membrane surface of the spiral membrane element, particularly contaminants clogged in the pores of the membrane. . This makes it possible to effectively clean the spiral membrane element.
[0061]
In addition, it is possible to effectively suppress the propagation of germs such as microorganisms on the membrane surface of the spiral membrane element by the chemical having a bactericidal action contained in the cleaning liquid.
[0062]
From the above, the spiral membrane module can be operated stably for a long time.
[0063]
According to a sixth aspect of the present invention, there is provided a method for cleaning a spiral membrane module in which a bag-shaped separation membrane is wound around the outer peripheral surface of a perforated hollow tube. And having first and second ends Cleaning of a spiral membrane module in which one or a plurality of spiral membrane elements capable of back-flow cleaning with a back pressure higher than 0.05 MPa and lower than 0.3 MPa are accommodated in a pressure vessel having a stock solution inlet and a stock solution outlet A method of introducing a cleaning liquid from at least one open end of a perforated hollow tube during back-flow cleaning to At least one of the first and second ends The separation liquid is discharged from the pressure vessel and taken out of the pressure vessel, and the separation membrane is backwashed at a back pressure higher than 0.05 MPa and lower than 0.3 MPa. Before the backwashing, at the backwashing or after the backwashing, Of the spiral membrane element through the stock solution inlet First end A cleaning liquid containing chemicals having a pollutant removing action or a bactericidal action is introduced from the flow of the cleaning liquid containing chemicals in the spiral type membrane element in the same direction as during filtration operation, and the spiral type membrane element Second end Derived from Operation , Take it out through the outlet of the pressure vessel, and pass through the outlet of the pressure vessel. Second end A cleaning liquid containing chemicals having a pollutant removing action or a sterilizing action is introduced from the inside, and the cleaning liquid containing chemicals flows in the spiral type membrane element in the reverse direction of the filtration operation, and the spiral type membrane element First end And take it out through the stock inlet of the pressure vessel Perform operations in order Is.
[0064]
In the method for cleaning a spiral membrane module according to the present invention, During backwashing, Since the separation membrane of the spiral membrane element can be backwashed with a back pressure higher than 0.05 MPa and lower than 0.3 MPa, a necessary amount of cleaning liquid can be flowed in a short time. Thereby, contaminants deposited on the membrane surface of the separation membrane can be effectively removed. As a result, it is possible to perform a stable filtration operation while maintaining a high permeation flux over a long period of time.
[0065]
Further, in the above method, the spiral membrane element is not cleaned before, during or after the backwashing. First A cleaning liquid containing a chemical having a pollutant removing action or a sterilizing action is introduced from the end, and the cleaning liquid containing the chemical flows in the spiral type membrane element in the same direction as the filtration operation, and the spiral type membrane element Second Derived from the end Operation Of spiral membrane element Second A cleaning liquid containing chemicals having a pollutant removing action or a sterilizing action is introduced from the end, and the cleaning liquid containing chemicals flows in the spiral type membrane element in the direction opposite to that during the filtration operation. First Derived from the end Operations are performed in order . As a result, it is possible to remove contaminants attached to the membrane surface of the spiral membrane element, in particular, contaminants that have formed a cake layer on the membrane surface. This makes it possible to always maintain a constant permeate amount during operation of the spiral membrane element.
[0066]
In particular, in this case, the contaminants attached to the membrane surface of the spiral membrane element can be easily removed by including the chemical having the contaminant peeling action in the cleaning liquid. This makes it possible to effectively clean the spiral membrane element.
[0067]
In addition, when the cleaning liquid contains a chemical having a bactericidal action, it is possible to effectively suppress the propagation of germs such as microorganisms on the membrane surface of the spiral membrane element.
[0068]
From the above, the spiral membrane element can be operated stably for a long time.
[0069]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic cross-sectional view showing an example of a spiral membrane module according to an embodiment of the present invention.
[0070]
As shown in FIG. 1, the spiral membrane module includes a spiral membrane element 1 housed in a pressure vessel (pressure vessel) 10. The pressure vessel 10 includes a cylindrical case 11 and a pair of end plates 12a and 12b. A raw water inlet 13 is formed in one end plate 12a, and a raw water outlet 15 is formed in the other end plate 12b. A permeated water outlet 14 is provided at the center of the other end plate 12b. The structure of the pressure vessel is not limited to the structure of FIG. 1, and a side-entry pressure vessel in which a raw water inlet and a raw water outlet are provided in a cylindrical case as will be described later may be used.
[0071]
The spiral membrane element 1 having a packing 17 attached in the vicinity of one end of the outer peripheral surface is loaded into the cylindrical case 11, and both open ends of the cylindrical case 11 are sealed with end plates 12a and 12b, respectively. One open end of the water collecting pipe 5 is fitted to the permeate outlet 14 of the end plate 12b, and an end cap 16 is attached to the other open end. The internal space of the pressure vessel 10 is separated into a first liquid chamber 18 and a second liquid chamber 19 by the packing 17.
[0072]
The raw water inlet 13 of the spiral membrane module is connected to the raw water tank 500 through a pipe 25. A valve 30a is inserted in the pipe 25, and a pipe 26 in which the valve 30b is inserted is connected to the downstream side of the valve 30a. On the other hand, the raw water outlet 15 is connected to a pipe 27 having a valve 30c inserted therein, and a pipe 27a having a valve 30d inserted therein is connected to the upstream side of the valve 27c of the pipe 27. The raw water outlet 15 is connected to the raw water tank 500 through the pipe 27a. The permeated water outlet 14 is connected to a pipe 28 having a valve 30e interposed therein, and a pipe 29 having a valve 30f inserted is connected to the upstream side of the valve 30e.
[0073]
FIG. 5 is a partially cutaway perspective view of a spiral membrane element used in the spiral membrane module of FIG.
[0074]
As shown in FIG. 5, the spiral membrane element 1 has an envelope-like membrane (bag-like membrane) 4 by superposing separation membranes 2 on both sides of a permeated water spacer 3 made of a synthetic resin net and adhering three sides. Is formed, and the opening of the envelope-like membrane 4 is attached to the water collecting pipe 5 and spirally wound around the outer peripheral surface of the water collecting pipe 5 together with the raw water spacer 6 made of a synthetic resin net. The outer peripheral surface of the spiral membrane element 1 is covered with an exterior material.
[0075]
In this spiral membrane element 1, it is possible to perform back-flow cleaning with a back pressure of 0.05 to 0.3 MPa by using a separation membrane 2 having a structure to be described later.
[0076]
2 and 3 are schematic cross-sectional views showing an example of a method for operating the spiral membrane module according to the present invention. In the operation method of this example, the spiral membrane module of FIG. 1 is used, FIG. 2 shows the operation method during filtration, and FIG. 3 shows the operation method during cleaning.
[0077]
As shown in FIG. 2, during filtration, the valve 30a of the pipe 25 and the valve 30e of the pipe 28 are opened, and the valve 30b of the pipe 26, the valve 30c of the pipe 27, the valve 30d of the pipe 27a, and the valve 30f of the pipe 29 are closed. .
[0078]
The raw water 7 taken from the raw water tank 500 is supplied to the inside of the pressure vessel 10 from the raw water inlet 13 through the pipe 25. In the spiral membrane module, the supplied raw water 7 is introduced from the raw water inlet 13 into the first liquid chamber 18 of the pressure vessel 10, and further, from one end of the spiral membrane element 1 to the inside of the spiral membrane element 1. Supplied.
[0079]
As shown in FIG. 5, in the spiral membrane element 1, the raw water 7 supplied from one end face side is directed to the other end face side in the direction (axial direction) parallel to the water collecting pipe 5 along the raw water spacer 6. Flowing in a straight line. In the process in which the raw water 7 flows along the raw water spacer 6, a part of the raw water 7 permeates the separation membrane 2 due to a pressure difference between the raw water side and the permeated water side. The permeated water 8 flows along the permeated water spacer 3 into the water collecting pipe 5 and is discharged from the end of the water collecting pipe 5. On the other hand, the remaining raw water 7 a that has not permeated the separation membrane 2 is discharged from the other end face side of the spiral membrane element 1.
[0080]
As shown in FIG. 2, the permeated water 8 discharged from the end of the water collecting pipe 5 is taken out from the pressure vessel 10 through the permeated water outlet 14 through the pipe 28. On the other hand, the raw water 7 a discharged from the other end face side of the spiral membrane element 1 is led out to the second liquid chamber 19. In this case, since the valve 30c of the pipe 27 and the valve 30d of the pipe 27a connected to the raw water outlet 15 are closed, the permeation of the separation membrane 2 in the spiral membrane element 1 is promoted and the entire amount is filtered.
[0081]
In the filtration process as described above, suspended substances, colloidal substances, or dissolved substances contained in the raw water are deposited as contaminants on the membrane surface of the separation membrane 2 of the spiral membrane element 1. In particular, contaminants are likely to deposit on the membrane surface of the separation membrane 2 in total filtration.
Such deposition of contaminants causes a decrease in the permeation rate of water, so the contaminants are removed by performing the following cleaning.
[0082]
As shown in FIG. 3, at the time of cleaning, first, the valve 30a of the pipe 25, the valve 30e of the pipe 28 and the valve 30d of the pipe 27a are closed, and the valve 30b of the pipe 26, the valve 30f of the pipe 29 and the valve 30c of the pipe 27 are closed. Open and backwash.
[0083]
At the time of backwashing, cleaning water 21 is supplied from the permeate outlet 14 to the open end of the water collecting pipe 5 through the pipe 29 and the pipe 28, and the cleaning water 21 is introduced into the water collecting pipe 5. For example, permeated water is used as the cleaning water 21. The washing water 21 introduced into the water collection pipe 5 is led out from the outer peripheral surface of the water collection pipe 5 to the inside of the separation membrane 2 and permeates the separation membrane 2 in the direction opposite to that during filtration. At this time, contaminants deposited on the membrane surface of the separation membrane 2 are peeled off from the separation membrane 2. Since the outer peripheral surface of the spiral membrane element 1 is covered with an exterior material, the cleaning water 21 that has permeated through the separation membrane 2 flows along the raw water spacer 6 in the axial direction inside the spiral membrane element 1 to form a spiral type. The liquid is discharged from both ends of the membrane element 1 to the first liquid chamber 18 and the second liquid chamber 19. Further, the washing water 21 is taken out from the raw water inlet 13 and the raw water outlet 15 through the pipe 26 and the pipe 27, respectively.
[0084]
In this case, the pressure on the permeate outlet 14 side, the pressure on the raw water inlet 13 side, and the pressure on the raw water outlet 15 side are set so that a back pressure of 0.05 to 0.3 MPa is applied to the separation membrane 2. Thereby, a necessary amount of the washing water 21 can be flowed in a short time, and the contaminants clogged in the pores of the separation membrane 2 can be effectively peeled off. Further, it is possible to prevent the pollutant from being removed by the raw water spacer 6 before the peeled pollutant is discharged from the end of the spiral membrane element 1, thereby effectively removing the pollutant.
[0085]
In this example, the entire amount of the wash water 21 taken out from the raw water inlet 13 is discharged out of the system as drainage. However, a part of the wash water 21 is discharged out of the system as drainage and part of the wash water 21 is discharged. It may be reused as raw water 7. For example, a part of the cleaning water 21 may be returned to the raw water tank 500 by providing a pipe further downstream of the valve 30 b of the pipe 26 and connecting this arrangement to the raw water tank 500.
[0086]
Further, in this example, the entire amount of the washing water 21 taken out from the raw water outlet 15 is discharged out of the system as waste water, but a part of this washing water 21 is discharged out of the system as waste water and part of it is discharged. It may be reused as raw water 7. For example, the valve 30c of the pipe 27 and the valve 30d of the pipe 27a may be opened, and a part of the cleaning water 21 may be returned to the raw water tank 500 through the pipe 27a.
[0087]
In the example of FIG. 3, the washing water 21 is discharged from both ends of the spiral membrane element 1 during backwashing, and is taken out from the raw water inlet 13 and the raw water outlet 15 through the pipe 26 and the pipe 27, respectively. The pressure on the permeate outlet 14 side and the pressure on the raw water inlet 13 side so that the washing water 21 is discharged from one end of the spiral membrane element 1 to the first liquid chamber 18 and taken out from the raw water inlet 13 through the pipe 26. May be set. In this case, the valve 30c of the pipe 27 is closed and the raw water outlet 15 is closed. Alternatively, the pressure on the permeate outlet 14 side and the raw water outlet 15 so that the cleaning water 21 is discharged from the other end of the spiral membrane element 1 to the second liquid chamber 19 and taken out from the raw water outlet 15 through the pipe 27. The side pressure may be set. In this case, the valve 30b of the pipe 26 is closed and the raw water inlet 13 is closed.
[0088]
After the backwashing is performed as described above, the valve 30b of the pipe 26 and the valve 30f of the pipe 29 are closed and the valve 30a of the pipe 25 is opened. As a result, the raw water 31 taken from the raw water tank 500 is supplied from the raw water inlet 13 into the pressure vessel 10 through the pipe 25 and introduced into the first liquid chamber 18. The raw water 31 is supplied from one end of the spiral membrane element 1 to the inside, flows in the spiral type membrane element 1 along the raw water spacer 6 in the axial direction, and then is discharged from the other end. As a result, contaminants separated from the separation membrane 2 are washed away from the one end portion of the spiral membrane element 1 together with the raw water 31 to the other end portion, and the spiral membrane element 1 together with the cleaning water 21 remaining inside the spiral membrane element 1. The other end of the liquid is discharged into the second liquid chamber 19. Further, the pollutant is taken out together with the raw water 31 from the raw water outlet 15 through the pipe 27 to the outside of the pressure vessel 10.
[0089]
In this way, by flowing the raw water 31 in the same direction as the raw water supply direction at the time of filtration after the backwashing, the contaminants separated from the separation membrane 2 in the spiral membrane element 1 can be quickly discharged out of the system. it can. Thereby, it is possible to prevent the contaminants separated from the separation membrane 2 from adhering to the separation membrane 2 again.
[0090]
According to the operation method at the time of cleaning as described above, it is possible to effectively remove the contaminants deposited on the separation membrane 2 at the time of filtration. It becomes possible to operate stably without causing a decrease in permeation flux over a long period of time.
[0091]
In this example, the raw water 31 is flowed in the axial direction after the backwashing, but the raw water 31 may be flowed in the axial direction before the backwashing. According to this cleaning method, most of the contaminant trapped on the membrane surface of the spiral membrane element 1 is removed by the raw water 31, and further, the cleaning water 21 is introduced to remain on the membrane surface of the spiral membrane element 1. To remove contaminants. Therefore, also in this case, the same effect as the above-described backwashing can be obtained.
[0092]
Alternatively, the raw water 31 may flow in the axial direction in parallel with the backwashing. For example, in the above, the valves 30a, 30b, 30c, and 30f of the pipes 25, 26, 27, and 29 may be simultaneously opened at the time of cleaning to supply the cleaning water 21 from the permeate side and the raw water 31 from the raw water side. In this case, the same effect as that obtained when the raw water 31 is allowed to flow after the backwashing as described above can be obtained.
[0093]
In this example, the raw water 31 is supplied from the raw water inlet 13 and taken out from the raw water outlet 15. However, the raw water is supplied from the raw water outlet 15 and taken out from the raw water inlet 13, and is filtered inside the spiral membrane element 1. The raw water may flow in the direction opposite to the raw water supply direction. In this case, the same effect as that obtained when the raw water 31 is allowed to flow in the same direction as the raw water supply direction at the time of filtration as described above can be obtained.
[0094]
In addition, when flowing raw water in the same direction as the raw water supply direction at the time of filtration, in particular, contaminants deposited on the side close to the second liquid chamber 19 of the spiral membrane element 1 should be easily removed and discharged. Is possible. On the other hand, when the raw water flows in the direction opposite to the supply direction of the raw water at the time of filtration, in particular, contaminants deposited on the side close to the first liquid chamber 18 of the spiral membrane element 1 are easily removed and discharged. Is possible.
[0095]
Moreover, you may flow raw | natural water in order in the same direction as the supply direction of raw | natural water at the time of filtration, and a reverse direction. In this case, contaminants distributed throughout the spiral membrane element 1 can be uniformly removed and discharged.
[0096]
In this example, the entire amount of the raw water 31 taken out from the raw water outlet 15 is discharged out of the system as waste water. However, a part of the raw water 31 is discharged out of the system as waste water and a part of the raw water 31 is recycled as raw water. May be used. For example, in the above, the valve 30c of the pipe 27 may be opened and the valve 30d of the pipe 27a may be opened, and a part of the raw water 31 may be returned to the raw water tank 500 through the pipe 27a.
[0097]
As described above, according to the operation method of this example shown in FIGS. 2 and 3, the contaminant deposited on the film surface of the spiral membrane element 1 can be sufficiently removed. The module can stably filter the whole amount while maintaining a high permeation flux, and can efficiently obtain the permeate 8. In this case, since the entire amount is filtered, it is not necessary to use a large pump for supplying the raw water 7, and the scale of the system can be reduced. Thereby, the system cost is reduced.
[0098]
Here, in this example, the supplied raw water 7 (FIG. 2) may contain chemicals such as sodium hypochlorite having a pollutant removing action such as dissolution, decomposition, peeling action, etc. of a pollutant or a bactericidal action. For example, when the raw water 7 containing sodium hypochlorite having a separating action and a bactericidal action for pollutants is supplied to the spiral membrane element 1, the pollutants attached to the membrane surface of the spiral membrane element 1 are peeled off, It is possible to suppress the deposition of microorganisms and to suppress the growth of microorganisms on the film surface. Thereby, in the spiral membrane element 1, more stable performance can be obtained over a long period of time.
[0099]
The raw water 7 may contain ozone, hydrogen peroxide, chloramine, or peracetic acid instead of sodium hypochlorite. Since these chemicals have a bactericidal action, it is possible to suppress the growth of microorganisms on the membrane surface of the spiral membrane element 1 as in the case of containing sodium hypochlorite.
[0100]
Here, the chemical | medical agent injection | pouring to the raw | natural water 7 is performed in the process until the raw | natural water 7 is supplied to a spiral membrane module, for example.
[0101]
Moreover, the chemical | medical agent injection | pouring to the raw | natural water 7 may be performed continuously always, or may be performed intermittently. When injecting chemicals intermittently, for example, the injection of chemicals is controlled by a timer. Alternatively, the state of contamination of the spiral membrane element 1 is checked from the operating pressure or the amount of permeated water, and chemicals are injected when contaminants accumulate on the spiral membrane element 1, that is, when the operating pressure increases or the amount of permeated water decreases. May be performed. In this case, for example, measuring instruments such as an operation pressure gauge, a permeate flow meter, and a transmembrane pressure gauge are installed in an apparatus in which a spiral membrane module is incorporated, and chemicals are injected in accordance with signals from these measuring instruments. .
[0102]
Furthermore, a flocculant may be injected into the raw water 7 in addition to the above-mentioned chemicals having a pollutant removing action and a bactericidal action. In this case, since the contaminants in the raw water 7 are aggregated, even a contaminant that permeates the membrane of the spiral membrane element without the aggregating agent is easily captured on the membrane surface of the spiral membrane element 1 by the aggregation action. Become. In addition, the contaminant trapped on the membrane surface of the spiral membrane element 1 in this way can be discharged out of the system by the backflow cleaning with the high back pressure as described above.
[0103]
On the other hand, in this example, as the cleaning water 21 (FIG. 3) used for the backflow cleaning, the permeated water 8 containing a chemical having a pollutant removing action such as a pollutant dissolving action, a decomposing action, and a peeling action may be used. . Moreover, you may use the permeated water 8 containing the chemical | medical agent which has a bactericidal action. For example, sodium hypochlorite with a concentration of 10 to 10,000 ppm, chloramine with a concentration of 0.1 to 10 ppm, hydrogen peroxide with a concentration of 10 to 10000 ppm, sulfuric acid with a pH of 1-3, nitric acid with a pH of 1-3, hydrochloric acid with a pH of 1-3, pH 10 Permeation containing ~ 13 sodium hydroxide, concentration 10-10000 ppm peracetic acid, concentration 0.1-50% isopropyl alcohol, concentration 0.2-2% citric acid or concentration 0.2-2% oxalic acid Water 8 is used as washing water 21. When the cleaning water 21 containing such a chemical is used, it is possible to effectively remove contaminants adhering to the membrane surface of the spiral membrane element 1, particularly clogged contaminants in the pores of the separation membrane 2. It becomes possible, and it becomes possible to suppress the propagation of microorganisms on the membrane surface.
[0104]
In particular, when the whole raw water 7 (FIG. 2) with high turbidity containing a lot of contaminants is filtered, a large amount of turbid components (contaminants) in the raw water 7 are trapped in the separation membrane 2 of the spiral membrane element 1. As a result, clogging occurs in the pores of the membrane. For this reason, it is difficult to completely remove the contaminants in the backflow cleaning using only the permeated water 8 as the cleaning water 21. In such a case, by using the permeated water 8 into which the chemical is injected as the cleaning water 21 for backflow cleaning, contaminants can be easily removed, and cleaning can be performed effectively.
[0105]
In addition, a chemical | medical agent may be continuously inject | poured into the permeated water 8, or you may inject | pour a chemical | medical agent after performing backflow washing | cleaning by the permeated water 8 several times.
[0106]
In this example, the raw water 31 (FIG. 3) that is supplied from at least one end of the spiral membrane element 1 and flows along the axial direction in the spiral membrane element 1 during cleaning removes the contaminants as described above. A chemical having an action or a bactericidal action may be included. When raw water 31 containing such chemicals is used, it is possible to easily remove contaminants adhering to the membrane surface of the spiral membrane element 1, particularly contaminants deposited on the membrane surface to form a cake layer. At the same time, it is possible to suppress the growth of microorganisms on the membrane surface.
[0107]
In particular, in the spiral type membrane element 1, when the clogging in the pores of the membrane due to the contaminants and the cake layer on the membrane surface formed by the deposition of the contaminants exist at the same time, In parallel with the introduction of cleaning water 21 containing chemicals from at least one open end to perform back-flow cleaning, the chemicals are regularly or periodically supplied from at least one end of the spiral membrane element 1 into the spiral membrane element 1. It is preferable to introduce the raw water 31 containing water and flow the inside of the spiral membrane element 1 along the axial direction. Thereby, clogging in the pores of the membrane of the spiral membrane element 1 and the cake layer formed on the membrane surface can be removed at the same time, and cleaning can be performed effectively.
[0108]
Further, at the time of cleaning the spiral membrane element 1, cleaning water 21 containing a chemical is introduced into the spiral membrane element 1 from the end of the water collecting pipe 2, or at least one end of the spiral membrane element 1. After the stock solution 31 containing chemicals is introduced, the spiral membrane element 1 may be immersed in the cleaning water 21 or stock solution 31 containing chemicals for several tens of minutes to several hours. As a result, contaminants clogged in the pores of the membrane of the spiral membrane element 1 and contaminants deposited on the membrane surface to form a cake layer are further easily removed, and cleaning is performed more effectively. In addition, it is possible to more effectively suppress the growth of microorganisms on the film surface. Further, the spiral membrane element 1 immersed in the cleaning water 21 containing chemicals or the stock solution 31 is further back-washed or the raw water 31 is flowed from one end of the spiral membrane element 1 to remove contaminants of the spiral membrane module. It becomes possible to discharge to the outside.
[0109]
The spiral type membrane element 1 is washed by such immersion once or several times a day, or for changes in the operating conditions of the spiral type membrane module, for example, an increase in operating pressure, a decrease in the amount of permeated water, etc. Do it accordingly.
[0110]
FIG. 4 is a schematic cross-sectional view showing another example of the operation method of the spiral membrane module according to the present invention. FIG. 4 shows an operation method at the time of filtration, and the spiral membrane module of FIG. 1 is also used in this example. In addition, the operation method at the time of washing | cleaning in this example is the same as the operation method of above-mentioned FIG.
[0111]
As shown in FIG. 4, at the time of filtration, the valve 30a of the pipe 25, the valve 30e of the pipe 28, and the valve 30d of the pipe 27a are opened, and the valve 30b of the pipe 26, the valve 30c of the pipe 27, and the valve 30f of the pipe 29 are closed. .
[0112]
In this case, as in the example of FIG. 2, the raw water 7 taken from the raw water tank 500 is introduced into the first liquid chamber 18 of the pressure vessel 10 from the raw water inlet 13 through the pipe 25. Further, the raw water 7 is supplied from one end of the spiral membrane element 1 into the spiral membrane element 1.
[0113]
As shown in FIG. 5, in the spiral membrane element 1, some raw water passes through the separation membrane 2 and flows into the water collection pipe 5, and is discharged from the end of the water collection pipe 5 as permeate 8. On the other hand, the remaining raw water 7 a that has not permeated the separation membrane 2 is discharged from the other end face side of the spiral membrane element 1.
[0114]
As shown in FIG. 4, the permeated water 8 discharged from the end of the water collecting pipe 5 is taken out from the pressure vessel 10 through the permeated water outlet 14 through the pipe 28. On the other hand, the raw water 7 a discharged from the other end face side of the spiral membrane element 1 is led out to the second liquid chamber 19, taken out from the raw water outlet 15 through the pipe 27 a, and returned to the raw water tank 500. . Thus, in this example, filtration is performed in the spiral membrane module while part of the raw water 7a is taken out from the raw water outlet 15 to the outside.
Thereby, it is possible to suppress the accumulation of liquid in the gap between the outer peripheral surface of the spiral membrane element 1 and the inner peripheral surface of the pressure vessel 10. Further, since a flow of raw water in the axial direction from one end to the other end is formed inside the spiral membrane element 1, a part of the pollutant is supplied to the raw water while suppressing sedimentation of the pollutant in the raw water. It becomes possible to discharge to the outside of the pressure vessel 10 together with 7a.
[0115]
In the above description, the valve 30d is always opened to take out the raw water 7a. However, the valve 30d may be opened intermittently to take out the raw water 7a. Even in this case, it is possible to suppress the contaminants from adhering to the separation membrane 2 as in the case of always taking out the raw water 7a.
[0116]
In the above description, the entire amount of the raw water 7a taken out of the pressure vessel is returned to the raw water tank 500. However, a part of the extracted raw water 7a may be discharged out of the system.
For example, the valve 30d may be opened and the valve 30c may be opened, and a part of the raw water 7a may be discharged out of the system through the pipe 27.
[0117]
Also in this example, at the time of cleaning, back-flow cleaning is performed with a high back pressure by the cleaning operation method shown in FIG. Thereby, it is possible to effectively remove the contaminants deposited on the separation membrane 2 during filtration.
[0118]
As described above, according to the operation method in this example, the contaminants deposited on the film surface can be sufficiently removed, so that the operation can be stably performed without causing a decrease in permeation flux over a long period of time. It becomes possible.
[0119]
In particular, in this example, as shown in FIG. 4, a part of the raw water 7 a is taken out of the pressure vessel 10 at the time of filtration, thereby suppressing the settling of the contaminants in the raw water onto the film surface. Since the part can be discharged to the outside of the pressure vessel 10 together with the raw water 7a, a more stable filtration operation can be performed. In this case, since the raw water 7a taken out from the raw water outlet 15 is circulated through the pipe 27a, it is possible to obtain the permeated water 8 with a high recovery rate. Moreover, it is not necessary to use a large pump for supplying the raw water 7, and the scale of the system can be reduced. Thereby, the system cost is reduced.
[0120]
In the operation of the spiral membrane element 1 in FIG. 4, as in the operation of the spiral membrane element 1 in FIG. 1, the supplied raw water 7 is used to remove or sterilize contaminants such as sodium hypochlorite. A chemical having an action may be included, or a flocculant may be included. Further, the permeated water 8 used as the cleaning water 21 at the time of cleaning and the raw water 31 supplied from at least the end of the spiral membrane element 1 at the time of cleaning have chemicals for removing or sterilizing contaminants such as sodium hypochlorite. May be included.
[0121]
In the above description, the case where the spiral membrane module including one spiral membrane element is operated has been described. However, the operation method according to the present invention includes a spiral membrane including a plurality of spiral membrane elements. It can also be applied to modules.
[0122]
FIG. 6 is a schematic cross-sectional view showing still another example of the operation method of the spiral membrane module according to the present invention.
[0123]
As shown in FIG. 6, the spiral-type membrane module of this example includes a plurality of spiral-type membrane elements 1 housed in a pressure vessel 100. The pressure vessel 100 includes a cylindrical case 111 and a pair of end plates 120a and 120b. A raw water inlet 130 is formed at the bottom of the cylindrical case 111, and a raw water outlet 131 is formed at the top. Thus, the pressure vessel 100 has a side entry shape. The raw water outlet 131 is also used for venting air. Further, a permeate outlet 140 is provided at the center of the end plates 120a and 120b.
[0124]
A plurality of spiral membrane elements 1 in which the water collecting pipes 5 are connected in series by the interconnector 116 are accommodated in the cylindrical case 111, and both open ends of the cylindrical case 111 are sealed with end plates 120a and 120b, respectively. The Here, the spiral membrane element 1 of FIG. 5 is used. One end of the water collecting pipe 5 of the spiral membrane element 1 at both ends is fitted to the permeate outlets 140 of the end plates 120a and 120b via the adapter 115, respectively. A packing 170 is attached in the vicinity of one end of the outer peripheral surface of each spiral membrane element 1, and the packing 170 separates the internal space of the pressure vessel 100 into a plurality of liquid chambers.
[0125]
The raw water inlet 130 of the spiral membrane module is connected to the raw water tank 500 through the pipe 55. A valve 60a is inserted in the pipe 55, and a pipe 56 in which a valve 60b is inserted is connected to the downstream side of the valve 30a. On the other hand, the raw water outlet 131 is connected to a pipe 57 in which a valve 60c is inserted, and a pipe 57a in which a valve 60d is inserted is connected to the upstream side of the valve 57c of the pipe 57. The raw water outlet 131 is connected to the raw water tank 500 through the pipe 57a. A pipe 58a having a valve 60e inserted therein is connected to the permeate outlet 140 on the end plate 120a side, and a pipe 59a having a valve 60g inserted therein is connected to the upstream side of the valve 60e. On the other hand, the permeate outlet 140 on the end plate 120b side is connected to a pipe 58b with a valve 60f inserted therein, and a pipe 59b with a valve 60h inserted into the upstream side of the valve 60f. Yes.
[0126]
During filtration of the spiral membrane module, the valve 60a of the pipe 55, the valve 60e of the pipe 58a and the valve 60f of the pipe 58b are opened, the valve 60b of the pipe 56, the valve 60g of the pipe 59a, the valve 60h of the pipe 59b, and the pipe 57 The valve 60c and the valve 60d of the pipe 57a are closed.
[0127]
The raw water 7 taken from the raw water tank 500 is supplied from the raw water inlet 130 into the pressure vessel 100 through the pipe 55. In the spiral membrane module, the raw water 7 supplied from the raw water inlet 130 is introduced into the spiral membrane element 1 from one end face side of the spiral membrane element 1 located at the end on the end plate 120a side. . In this spiral membrane element 1, as shown in FIG. 5, some raw water permeates the separation membrane 2 and flows into the water collection pipe 5, and is discharged from the end of the water collection pipe 5 as permeate 8. . On the other hand, the remaining raw water 7a that has not permeated the separation membrane 2 is discharged from the other end face side. The discharged raw water 7a is introduced into the spiral membrane element 1 from one end face side of the subsequent spiral membrane element 1 and separated into the permeated water 8 and the raw water 7a in the same manner as described above. Thus, membrane separation is performed in each of the plurality of spiral membrane elements 1 connected in series. In this case, since the valve 60c of the pipe 57 and the valve 60d of the pipe 57a are closed, the permeation of the separation membrane 2 is promoted in each spiral membrane element 1 as in the example of FIG. Is done.
[0128]
In the above filtration process, contaminants contained in the raw water are deposited on the membrane surface of the separation membrane 2 of each spiral membrane element 1. In particular, if the entire amount is filtered in a spiral membrane module having a plurality of spiral membrane elements 1 as described above, contaminants are likely to deposit on the membrane surface of the separation membrane 2. Such deposition of contaminants causes a decrease in the permeation rate of water, so the contaminants are removed by performing the following cleaning.
[0129]
When cleaning, first, the valve 60a of the pipe 55, the valve 60e of the pipe 58a, the valve 60f of the pipe 58b and the valve 60d of the pipe 57a are closed, and the valve 60b of the pipe 56, the valve 60c of the pipe 57, the valve 60g of the pipe 59a and the pipe The valve 60h of 59b is opened to perform back-flow cleaning.
[0130]
At the time of backwashing, on the end plate 120a side, the wash water 21 is supplied from the permeate outlet 140 to one end of the water collecting pipe 5 through the pipe 59a and the pipe 58a. On the end plate 120b side, the wash water 21 is supplied from the permeate outlet 140 to the other end of the water collecting pipe 5 through the pipe 59b and the pipe 58b. In this way, the wash water 21 is introduced into the water collection pipe 5 from both ends of the water collection pipe 5. The wash water 21 introduced into the water collection pipe 5 is led out from the outer peripheral surface of the water collection pipe 5 to the inside of the separation membrane 2 in each spiral membrane element 1 and permeates the separation membrane 2 in the direction opposite to that during filtration. At this time, contaminants deposited on the membrane surface of the separation membrane 2 are peeled off from the separation membrane 2. The washing water 21 that has passed through the separation membrane 2 flows in the axial direction inside the spiral membrane element 1 along the raw water spacer 6, and is discharged from both ends of each spiral membrane element 1. The discharged wash water 21 is taken out from the raw water inlet 130 and the raw water outlet 131 to the outside through the pipe 56 and the pipe 57, respectively.
[0131]
In this case, the pressure on the permeate outlet 140 side, the pressure on the raw water inlet 130 side, and the pressure on the raw water outlet 131 side are set so that a back pressure of 0.05 to 0.3 MPa is applied to the separation membrane 2 of each spiral membrane element 1. Set. Accordingly, a necessary amount of the cleaning water 21 can be flowed in a short time, and the contaminants deposited on the membrane surface of the separation membrane 2 can be effectively peeled off. Further, it is possible to prevent the polluted substances from being trapped by the raw water spacers 6 until they are discharged from the end of each spiral membrane element 1 and effectively remove the pollutants.
[0132]
In this example, the entire amount of the washing water 21 taken out from the raw water inlet 130 is discharged out of the system as waste water, but a part of the washing water 21 is discharged out of the system as waste water, and part of it is discharged. It may be reused as raw water 7. For example, a part of the cleaning water 21 may be returned to the raw water tank 500 by providing a pipe further downstream of the valve 60 b of the pipe 56 and connecting this arrangement to the raw water tank 500.
[0133]
Further, in this example, the entire amount of the washing water 21 taken out from the raw water outlet 131 is discharged out of the system as waste water, but a part of this washing water 21 is discharged out of the system as waste water, and part of it is discharged. It may be reused as raw water 7. For example, the valve 60c of the pipe 57 and the valve 60d of the pipe 57a may be opened, and a part of the cleaning water 21 may be returned to the raw water tank 500 through the pipe 57a.
[0134]
In the example of FIG. 6, the cleaning water 21 is taken out from the raw water inlet 130 and the raw water outlet 131 through the pipe 56 and the pipe 57 at the time of backwashing. The pressure on the permeate outlet 140 side and the pressure on the raw water inlet 130 side may be set so as to be taken out. In this case, the valve 60c of the pipe 57 is closed and the raw water outlet 131 is closed. Alternatively, the pressure on the permeated water outlet 140 side and the pressure on the raw water outlet 131 side may be set so that the wash water 21 is taken out from the raw water outlet 131 through the pipe 57. In this case, the valve 60b of the pipe 56 is closed and the raw water inlet 130 is closed.
[0135]
After the backflow cleaning is performed as described above, the valve 60b of the pipe 56, the valve 60g of the pipe 59a, and the valve 60h of the pipe 59b are closed, and the valve 60a of the pipe 55 is opened. Thereby, the raw water 31 taken from the raw water tank 500 is supplied from the raw water inlet 130 into the pressure vessel 100 through the pipe 55. In each spiral membrane element 1, the raw water 31 is introduced from one end portion of the spiral membrane element 1 into the spiral membrane element 1, flows axially along the raw water spacer 6 in the spiral membrane element 1, and then is discharged from the other end portion. Is done. As a result, the contaminants peeled off from the separation membrane 2 are pushed away from the one end to the other end of the spiral membrane element 1 by the raw water 31, and together with the cleaning water 21 remaining inside the spiral membrane element 1, the spiral membrane element 1. It is discharged from the other end. Further, the pollutant and the cleaning water 21 are taken out from the pressure vessel 100 through the pipe 57 from the raw water outlet 131 together with the raw water 31.
[0136]
As described above, by flowing the raw water 31 in the same direction as the supply direction of the raw water at the time of filtration after the backwashing, the contaminants separated from the separation membrane 2 in each spiral membrane element 1 can be quickly discharged out of the system. Can do. Thereby, it is possible to prevent the contaminants separated from the separation membrane 2 from adhering to the separation membrane 2 again.
[0137]
In this example, the raw water 31 is flowed in the axial direction after the backwashing, but the raw water 31 may be flowed in the axial direction before the backwashing. According to this cleaning method, most of the contaminant trapped on the membrane surface of the spiral membrane element 1 is removed by the raw water 31, and further, the cleaning water 21 is introduced to remain on the membrane surface of the spiral membrane element 1. To remove contaminants. Therefore, also in this case, the same effect as the above-described backwashing can be obtained.
[0138]
Alternatively, the raw water 31 may flow in the axial direction in parallel with the backwashing. For example, in the above, at the time of cleaning, the valves 60a, 60b, 60c, 60g, 60h of the pipes 55, 56, 57, 59a, 59b are simultaneously opened to supply the cleaning water 21 from the permeate side and the raw water 31 from the raw water side. Also good. In this case, the same effect as that obtained when the raw water 31 is allowed to flow after the backwashing as described above can be obtained.
[0139]
In this example, the raw water 31 is supplied from the raw water inlet 130 and taken out from the raw water outlet 131. However, the raw water is supplied from the raw water outlet 131 and taken out from the raw water inlet 130, and is filtered inside each spiral membrane element 1. The raw water may be flowed in the direction opposite to the direction in which the raw water is supplied. In this case, the same effect as that obtained when the raw water 31 is allowed to flow in the same direction as the raw water supply direction at the time of filtration as described above can be obtained. Or you may flow raw | natural water in order in the same direction as the supply direction of raw | natural water at the time of filtration, and a reverse direction. In this case, contaminants distributed throughout the spiral membrane element 1 can be uniformly removed and discharged.
[0140]
Further, in this example, the entire amount of the raw water 31 taken out from the raw water outlet 131 is discharged out of the system as waste water. However, a part of the raw water 31 is discharged out of the system as waste water and part of the raw water 7 is discharged. May be reused as For example, in the above, the valve 60c of the pipe 57 and the valve 60d of the pipe 57a may be opened, and a part of the raw water 31 may be returned to the raw water tank 500 through the pipe 57a.
[0141]
According to the operation method at the time of cleaning as described above, it is possible to effectively remove contaminants deposited on the separation membrane 2 during filtration.
[0142]
As described above, according to the operation method in this example, the contaminants deposited on the film surface can be sufficiently removed, so that a high permeation flux can be obtained even in the total amount filtration where the contaminants easily deposit on the film surface. It is possible to operate stably while maintaining and to obtain the permeated water 8 efficiently. In this case, since the entire amount is filtered, it is not necessary to use a large pump for supplying the raw water 7, and the scale of the system can be reduced. Thereby, the system cost is reduced.
[0143]
Also in this example, as in the method of operating the spiral membrane element and spiral membrane module shown in FIG. 1, the supplied raw water 7 contains chemicals such as sodium hypochlorite having a pollutant removing or sterilizing action. May be included. In this case, it is possible to remove contaminants adhering to the membrane surface of each spiral membrane element 1 to suppress the accumulation of contaminants and to suppress the growth of microorganisms on the membrane surface. . Thereby, in the spiral membrane module, more stable performance can be obtained over a long period of time.
[0144]
Further, at the time of cleaning the spiral membrane module, the permeated water 8 containing a chemical having a function of removing contaminants such as sodium hypochlorite or a sterilizing function may be used as the cleaning water 21 for backflow cleaning. In this case, contaminants clogged in the pores of the spiral membrane element 1 can be effectively removed, and the growth of microorganisms on the membrane surface can be suppressed. Thereby, in the spiral membrane module, more stable performance can be obtained over a long period of time.
[0145]
Further, raw water 31 containing a chemical having a pollutant removing action or a sterilizing action may be supplied from at least one end of the spiral membrane element 1 at the time of cleaning. In this case, it is possible to effectively remove contaminants deposited on the membrane surface of each spiral membrane element 1 to form a cake layer, and to suppress the growth of microorganisms on the membrane surface. Become. Thereby, in the spiral membrane module, more stable performance can be obtained over a long period of time.
[0146]
In the above description, the case where the total amount filtration is performed using the spiral membrane module of FIG. 6 as in the example of FIG. 2 has been described. However, the spiral membrane module of FIG. Filtration may be performed while taking out a part of the raw water 7a outside the pressure vessel 100.
[0147]
For example, during the filtration of the spiral membrane module of FIG. 6, the valve 60d of the pipe 57a is opened constantly or intermittently and permeates the separation membrane 2 of the spiral membrane element 1 in the raw water 7 supplied into the pressure vessel 100. A portion of the raw water 7a that has not been taken may be taken out of the pressure vessel 100 from the raw water outlet 131 through the pipe 57a and returned to the raw water tank 500. Thereby, it is possible to suppress the accumulation of liquid in the gap between the outer peripheral portion of each spiral membrane element 1 and the inner peripheral surface of the pressure vessel 100. In addition, since the flow of the raw water in the axial direction from one end to the other end is formed inside each spiral membrane element 1, a part of the pollutants is supplied to the raw water while suppressing sedimentation of the pollutants in the raw water. It becomes possible to discharge to the outside of the pressure vessel together with 7a.
[0148]
According to such an operation method of performing filtration while taking out a part of the raw water, it becomes possible to perform operation more stably without causing a decrease in permeation flux over a long period of time. In this case, since the raw water 7a taken out is circulated through the pipe 57a, it is possible to obtain the permeated water 8 with a high recovery rate. Moreover, it is not necessary to use a large pump for supplying the raw water 7, and the scale of the system can be reduced. Thereby, the system cost is reduced.
[0149]
FIG. 7 is a cross-sectional view of a separation membrane used in the spiral membrane element of FIG. The separation membrane 2 is formed by tightly integrating a permeable membrane body 2b having a substantial separation function on the surface of a porous reinforcing sheet (porous sheet material) 2a.
[0150]
The permeable membrane body 2b is formed from one type of polysulfone resin, or a mixture of two or more types of polysulfone resins, or a copolymer or mixture of a polysulfone resin and a polymer such as polyimide or fluorine-containing polyimide resin. Is done.
[0151]
The porous reinforcing sheet 2a is formed from a woven fabric, a nonwoven fabric, a mesh net, a foamed sintered sheet or the like made of polyester, polypropylene, polyethylene, polyamide or the like, and is preferably a nonwoven fabric from the viewpoint of film forming property and cost. .
[0152]
The porous reinforcing sheet 2a and the permeable membrane body 2b are joined in a throwing state in which a part of the resin component constituting the permeable membrane body 2b is filled in the pores of the porous reinforcing sheet 2a.
[0153]
The back pressure strength of the separation membrane 2 backed by the porous reinforcing sheet 2a exceeded 0.2 MPa and improved to about 0.4 to 0.5 MPa. A method for defining the back pressure strength will be described later.
[0154]
In order to obtain a back pressure strength of 0.2 MPa or more using a nonwoven fabric as the porous reinforcing sheet 2a, the nonwoven fabric has a thickness of 0.08 to 0.15 mm and a density of 0.5 to 0.8 g / cm. ^Three It is preferable that If the thickness is less than 0.08mm or the density is 0.5g / cm ^Three If it is smaller, the strength as the reinforcing sheet cannot be obtained, and it is difficult to secure the back pressure strength of the separation membrane 2 of 0.2 MPa or more. On the other hand, the thickness is thicker than 0.15 mm or the density is 0.8 g / cm. ^Three If larger, the filtration resistance of the porous reinforcing sheet 2a is increased, the anchoring effect on the nonwoven fabric (porous reinforcing sheet 2a) is reduced, and peeling is likely to occur at the interface between the permeable membrane body 2b and the nonwoven fabric. Become.
[0155]
Next, the manufacturing method of said separation membrane 2 is demonstrated. First, a solvent, a non-solvent, and a swelling agent are added to polysulfone and dissolved by heating to prepare a uniform film forming solution. Here, as shown in the following structural formula (Chemical Formula 1), the polysulfone resin has at least one (—SO 2) in the molecular structure. ₂ If it has a-) site | part, it will not specifically limit.
[0156]
[Chemical 1]

[0157]
R represents a divalent aromatic, alicyclic or aliphatic hydrocarbon group, or a divalent organic group in which these hydrocarbon groups are bonded by a divalent organic bonding group.
[0158]
Preferably, polysulfone represented by the following structural formulas (Chemical Formula 2) to (Chemical Formula 4) is used.
[0159]
[Chemical 2]

[0160]
[Chemical 3]

[0161]
[Formula 4]

[0162]
As the polysulfone solvent, it is preferable to use N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, dimethylsulfoxide, or the like. Further, as the non-solvent, aliphatic polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, polyethylene glycol and glycerin, lower aliphatic alcohols such as methanol, ethanol and isopropyl alcohol, lower aliphatic ketones such as methyl ethyl ketone, and the like are used. It is preferable.
[0163]
The content of the non-solvent in the mixed solvent of the solvent and the non-solvent is not particularly limited as long as the obtained mixed solvent is uniform, but is usually 5 to 50% by weight, preferably 20 to 45% by weight.
[0164]
Swelling agents used to promote or control the formation of porous structures include metal salts such as lithium chloride, sodium chloride, and lithium nitrate, and water solubility such as polyethylene glycol, polyvinyl alcohol, polyvinyl pyrrolidone, and polyacrylic acid. A polymer or a metal salt thereof, formamide or the like is used. The content of the swelling agent in the mixed solvent is not particularly limited as long as the film-forming solution is uniform, but is usually 1 to 50% by weight.
[0165]
The concentration of polysulfone in the membrane forming solution is usually preferably 10 to 30% by weight. When it exceeds 30% by weight, the water permeability of the resulting porous separation membrane is poor in practicality, and when it is less than 10% by weight, the mechanical strength of the resulting porous separation membrane is poor and sufficient back pressure is obtained. Can't get strength.
[0166]
Next, the above film forming solution is formed on a nonwoven fabric support. That is, using a continuous film forming apparatus, a support sheet such as a nonwoven fabric is sequentially sent out, and a film forming solution is applied to the surface. As a coating method, the film forming solution is coated on the nonwoven fabric support using a gap coater such as a knife coater or a roll coater. For example, when using a roll coater, the film forming solution is stored between two rolls, and the film forming solution is applied onto the nonwoven fabric support and simultaneously impregnated inside the nonwoven fabric, and then passed through a low humidity atmosphere. Then, a minute amount of moisture in the atmosphere is absorbed on the surface of the liquid film coated on the nonwoven fabric, and microphase separation is caused in the surface layer of the liquid film. Then, it is immersed in a coagulation water tank, the entire liquid film is phase-separated and coagulated, and the solvent is washed away in the water washing tank. Thereby, the separation membrane 2 is formed.
[0167]
As described above, since the separation membrane 2 has high back pressure strength, even when the separation membrane 2 is used for the spiral membrane element 1 of FIGS. The separation membrane 2 is prevented from being damaged.
[0168]
【Example】
In the following Examples 1 to 3 and Comparative Examples, a spiral type ultrafiltration membrane element including an ultrafiltration membrane having the structure shown in FIG. 7 as the separation membrane 2 was produced, and this spiral type ultrafiltration membrane element was A continuous water filtration test was performed using the spiral membrane module of FIG.
[0169]
The specifications of the spiral ultrafiltration membrane elements used in Examples 1 to 3 and the comparative example are as shown in Table 1 below.
[0170]
[Table 1]

[0171]
Here, the ultrafiltration membranes used in the spiral ultrafiltration membrane elements of Examples 1 to 3 and the comparative example were produced as follows.
[0172]
First, 16.5 parts by weight of polysulfone (Amoco, P-3500), 50 parts by weight of N-methyl-2pyrrolidone, 24.5 parts by weight of diethylene glycol, and 1 part by weight of formamide were heated and dissolved to obtain a uniform product. A membrane solution was obtained. And using a roll coater with the coater gap adjusted to 0.13 mm, the thickness is 0.1 mm and the density is 0.8 g / cm. ^Three The film forming solution was impregnated and applied to the surface of the polyester nonwoven fabric.
[0173]
Then, after passing through an atmosphere (low humidity atmosphere) having a relative humidity of 25% and a temperature of 30 ° C. at a predetermined speed to cause microphase separation, it was immersed in a coagulated water tank at 35 ° C. to remove the solvent. After solidification, the separation solvent 2 was obtained by washing and removing the remaining solvent in a water washing tank. Here, the separation membrane 2 of Example 1 and Example 2 has a microphase separation time (time for passing through a low-humidity atmosphere) of 4.5 seconds.
[0174]
The ultrafiltration membrane produced as described above has a water permeability of 1700 L / m. ² -Hr, the back pressure strength was 0.3 MPa, and the rejection of polyethylene oxide having an average molecular weight of 1,000,000 was 99%.
[0175]
For the back pressure strength, a membrane having a diameter of 47 mm is set in a back pressure strength holder (having a hole diameter of 23 mm), and water pressure is gradually applied from the porous reinforcing sheet 2a side. It is defined by the pressure at which the permeable membrane body 2b and the porous reinforcing sheet 2a are simultaneously ruptured.
[0176]
The rejection rate of polyethylene oxide is such that a polyethylene oxide solution having a concentration of 500 ppm is applied at a pressure of 1 kgf / cm. ² And obtained from the concentration of the stock solution and the permeate by the following formula.
[0177]
Blocking rate (%) [1- (permeate concentration / stock solution concentration)] × 100
Next, the continuous water filtration test of the spiral membrane module provided with the ultrafiltration membrane thus produced will be described below. In this case, industrial water (pH 6-8, water temperature 15-30 ° C.) was supplied as raw water 7 in the continuous water filtration test.
[0178]
[Example 1]
In Example 1, sodium hypochlorite having a bactericidal action and a contaminant removing action was always injected into the raw water 7 supplied to the spiral membrane module of FIG. The operating conditions of the spiral membrane module in Example 1 are shown in Table 2 below.
[0179]
[Table 2]

[0180]
During back-flow cleaning, permeated water 8 (FIG. 2) is used as cleaning water 21 (FIG. 3), and cleaning water 21 is supplied at a flow rate of 56 L / min with a back pressure of 0.1 to 0.2 MPa. It was. Further, in this case, the raw water 31 (FIG. 3) is supplied to the spiral membrane module after backwashing, and in the same direction as the supply direction of the raw water 7 (FIG. 2) during filtration inside the spiral ultrafiltration membrane element. Raw water 31 was poured.
[0181]
The spiral ultrafiltration membrane element was continuously operated while repeating the filtration and washing as described above. Then, the relationship between the operation time and the transmembrane pressure difference in the spiral ultrafiltration membrane element was examined.
[0182]
[Example 2]
In the second embodiment, sodium hypochlorite having a sterilizing action and a contaminant removing action is injected into the washing water 21 (FIG. 3) during the backwashing of the spiral membrane module of FIG. Washing with back water was performed. The operating conditions of the spiral membrane module in Example 2 are shown in Table 3 below.
[0183]
[Table 3]

[0184]
During back-flow cleaning, permeated water 8 (FIG. 2) is used as cleaning water 21 (FIG. 3), and cleaning water 21 is supplied at a flow rate of 56 L / min with a back pressure of 0.1 to 0.2 MPa. It was. Further, in this case, the raw water 31 (FIG. 3) is supplied to the spiral membrane module after backflow cleaning, and in the same direction as the supply direction of the raw water 7 (FIG. 2) during filtration inside the spiral ultrafiltration membrane element. Raw water 31 was poured.
[0185]
The spiral ultrafiltration membrane element was continuously operated while repeating the filtration and washing as described above. Then, the relationship between the operation time and the transmembrane pressure difference in the spiral ultrafiltration membrane element was examined.
[0186]
[Example 3]
In Example 3, the spiral membrane module of FIG. 1 was operated continuously for 5 days, and then the cleaning water injected with sodium hypochlorite having a bactericidal action and a contaminant removing action was supplied to the spiral membrane module. The spiral ultrafiltration membrane element was subjected to immersion cleaning. The operating conditions of the spiral membrane module in Example 3 are shown in Table 4 below.
[0187]
[Table 4]

[0188]
During back-flow cleaning, permeated water 8 (FIG. 2) is used as cleaning water 21 (FIG. 3), and cleaning water 21 is supplied at a flow rate of 56 L / min with a back pressure of 0.1 to 0.2 MPa. It was. Further, in this case, the raw water 31 (FIG. 3) is supplied to the spiral membrane module after backwashing, and in the same direction as the supply direction of the raw water 7 (FIG. 2) during filtration inside the spiral ultrafiltration membrane element. Raw water 31 was poured.
[0189]
In this example, sodium hypochlorite is appropriately injected into the cleaning water 21 for backflow cleaning during immersion cleaning, and the cleaning water 21 into which this sodium hypochlorite has been injected is used as cleaning water for immersion cleaning. It was.
[0190]
The spiral membrane module was continuously operated while repeating the filtration and washing as described above. Then, the relationship between the operation time and the transmembrane pressure difference in the spiral ultrafiltration membrane element was examined.
[0191]
[Comparative example]
In the comparative example, no chemicals were injected during the filtration operation and cleaning of the spiral membrane module of FIG. The operating conditions of the spiral membrane module in the comparative example are shown in Table 5 below.
[0192]
[Table 5]

[0193]
At the time of backflow cleaning, the permeated water 8 (FIG. 2) is used as the cleaning water 21 (FIG. 3), and the cleaning water 21 is supplied at a flow rate of 56 L / min with a back pressure of 0.1 to 0.2 MPa. It was. Further, in this case, the raw water 31 (FIG. 3) is supplied to the spiral membrane module after backflow cleaning, and in the same direction as the supply direction of the raw water 7 (FIG. 2) during filtration inside the spiral ultrafiltration membrane element. Raw water 31 was poured.
[0194]
The spiral membrane module was continuously operated while repeating the filtration and washing as described above. Then, the relationship between the operation time and the transmembrane pressure difference in the spiral ultrafiltration membrane element was examined.
[0195]
FIG. 8 is a diagram showing the change with time of the transmembrane pressure difference of the spiral membrane module in Examples 1 to 3 and Comparative Example.
[0196]
As shown in FIG. 8, in Example 1 in which sodium hypochlorite was always injected into the raw water 7, it was possible to suppress the growth of microorganisms on the membrane surface and to prevent the adhesion of contaminants to the membrane surface. be able to. For this reason, the change in the transmembrane pressure difference of the spiral ultrafiltration membrane element is small, and it has been possible to continuously perform a stable operation for a long time in the spiral membrane module.
[0197]
Further, in Example 2 in which sodium hypochlorite was injected into the washing water 21 at the time of backwashing, since the membrane surface was in contact with sodium hypochlorite only at regular intervals, the effect was lower than that in Example 1. Become. However, even in this case, the increase in the transmembrane pressure difference can be sufficiently suppressed in the spiral ultrafiltration membrane element, and the change in the transmembrane pressure difference can be reduced. Therefore, in the spiral membrane module, stable operation can be continuously performed for a long time.
[0198]
On the other hand, in Example 3, since the chemical injection is not performed at the time of filtration and backwashing, the transmembrane pressure difference increases with the passage of operation time. However, in this case, since the immersion cleaning is performed with the cleaning water containing sodium hypochlorite as the transmembrane differential pressure increases, it is possible to suppress the increase in transmembrane differential pressure. Therefore, in the spiral membrane module, stable operation can be continuously performed for a long time.
[0199]
On the other hand, in the comparative example in which no chemical was injected at the time of filtration and washing, the continuous transmembrane pressure was increased with the lapse of operation time, so that continuous operation could not be continued.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an example of a spiral membrane module according to an embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view showing an example of a method for operating a spiral membrane module according to the present invention.
FIG. 3 is a schematic cross-sectional view showing an example of a method for operating a spiral membrane module according to the present invention.
FIG. 4 is a schematic cross-sectional view showing another example of a method for operating a spiral membrane module according to the present invention.
5 is a partially cutaway perspective view of a spiral membrane element used in the spiral membrane module of FIG. 1. FIG.
FIG. 6 is a schematic cross-sectional view showing still another example of a method for operating a spiral membrane module according to the present invention.
7 is a cross-sectional view of a separation membrane used in the spiral membrane element of FIG.
FIG. 8 is a graph showing changes over time in transmembrane pressure difference of spiral membrane modules of Examples 1 to 3 and Comparative Example.
[Explanation of symbols]
1 Spiral membrane element
2 Separation membrane
3 Permeated water spacer
4 Envelope film
5 water collecting pipe
6 Raw water spacer
7,31 Raw water
8 Permeated water
10,100 pressure vessel
13,130 Raw water entrance
14,140 Permeate outlet
15,131 Raw water outlet
21 Washing water

Claims (16)

  A bag-shaped separation membrane is wound around the outer peripheral surface of the perforated hollow tube and has first and second end portions, and back-flow cleaning is performed with a back pressure higher than 0.05 MPa and lower than 0.3 MPa. A method for operating a spiral membrane element, wherein a stock solution is supplied from the first end of the spiral membrane element during filtration operation and a permeate is supplied from at least one open end of the perforated hollow tube. Taking out the cleaning liquid from at least one of the open ends of the perforated hollow tube and discharging the cleaning liquid from at least one of the first and second ends of the spiral membrane element at the time of backwashing. The separation membrane is backwashed with a back pressure higher than 05 MPa and less than or equal to 0.3 MPa, and the spiral membrane element before the backwashing, during the backwashing or after the backwashing. A stock solution containing a chemical having a pollutant removing action or a bactericidal action is introduced from an end of the spiral-type membrane element, and the stock solution is caused to flow in the spiral membrane element in a direction opposite to that during the filtration operation. A method of operating a spiral membrane element, wherein the spiral membrane element is led out from an end.   2. The method of operating a spiral membrane element according to claim 1, wherein the chemical is sodium hypochlorite, chloramine, hydrogen peroxide, peracetic acid or ozone.   3. The method for operating a spiral membrane element according to claim 1, wherein the stock solution containing the chemical contains a flocculant.   A cleaning liquid derived from an outer peripheral surface of the perforated hollow tube by introducing a cleaning liquid containing a chemical having a pollutant peeling action or a bactericidal action from at least one open end of the perforated hollow pipe during the backflow cleaning. The back-flushing of the separation membrane is performed at a back pressure higher than 0.05 MPa and lower than 0.3 MPa by discharging from at least one of the first and second ends of the spiral membrane element. Item 4. A method for operating a spiral membrane element according to any one of Items 1 to 3.   5. The method of operating a spiral membrane element according to claim 4, wherein the cleaning liquid is a permeate.   At the time of the backflow cleaning, a cleaning liquid containing a chemical having a pollutant removing action or a bactericidal action is supplied from at least one of the first and second ends of the spiral type membrane element, and the chemical is supplied in the spiral type membrane element. The method of operating a spiral membrane element according to any one of claims 1 to 3, wherein a cleaning liquid containing is flowed in the axial direction.   The method of operating a spiral membrane element according to claim 6, wherein the cleaning liquid is a stock solution.   The separation membrane is formed by bonding a permeable membrane body to one surface of a porous sheet material, and the permeable membrane body is bonded to one surface of the porous sheet material in an anchored state. A method for operating the spiral membrane element according to any one of claims 7 to 10.   A bag-shaped separation membrane is wound around the outer peripheral surface of the perforated hollow tube and has first and second end portions, and back-flow cleaning is performed with a back pressure higher than 0.05 MPa and lower than 0.3 MPa. A method for cleaning a spiral membrane element, wherein a cleaning liquid is introduced from at least one open end of the perforated hollow tube during back-flow cleaning, and the first and second ends of the spiral membrane element are The separation membrane is backwashed at a back pressure higher than 0.05 MPa and lower than 0.3 MPa by discharging from at least one side, and the spiral membrane element before the backwashing, during the backwashing or after the backwashing A stock solution containing a chemical having a pollutant removing action or a bactericidal action is introduced from the second end, and the stock solution is caused to flow in the spiral membrane element in the direction opposite to that during the filtration operation. The method of cleaning the spiral membrane element, characterized by deriving from said first end of Iraru membrane element.   A bag-shaped separation membrane is wound around the outer peripheral surface of the perforated hollow tube and has first and second end portions, and back-flow cleaning is performed with a back pressure higher than 0.05 MPa and lower than 0.3 MPa. A method for cleaning a spiral membrane element, wherein a cleaning liquid is introduced from at least one open end of the perforated hollow tube during back-flow cleaning, and the first and second ends of the spiral membrane element are The separation membrane is backwashed at a back pressure higher than 0.05 MPa and lower than 0.3 MPa by discharging the cleaning liquid from at least one of the spiral-type membranes before the backwashing, during the backwashing, or after the backwashing. During the filtration operation of the cleaning liquid containing the chemical in the spiral membrane element by introducing a cleaning liquid containing the chemical having a pollutant removing action or a sterilizing action from the first end of the element. An operation of flowing in the same direction and leading out from the second end of the spiral membrane element, and a cleaning liquid containing a chemical having a contaminant peeling action or a sterilizing action from the second end of the spiral membrane element Introducing and flowing the cleaning liquid containing the chemical in the spiral membrane element in the direction opposite to that during the filtration operation, and conducting the operation of deriving from the first end portion of the spiral membrane element in order. A method for cleaning spiral membrane elements.   The first and second of the spiral membrane element are always or periodically in parallel with the introduction of the cleaning liquid containing the chemical from the opening end of at least one of the perforated hollow tubes and performing the back-flow cleaning. The method for cleaning a spiral membrane element according to claim 9 or 10, wherein a cleaning liquid containing the chemical is supplied from at least one of the end portions.   The method for cleaning a spiral membrane element according to any one of claims 9 to 11, wherein the spiral membrane element is immersed in a cleaning liquid containing the chemical.   The said chemical | medical agent is sodium hypochlorite, chloramine, hydrogen peroxide, a sulfuric acid, hydrochloric acid, nitric acid, sodium hydroxide, peracetic acid, isopropyl alcohol, oxalic acid, or a citric acid, The any one of Claims 9-12 characterized by the above-mentioned. A method for cleaning a spiral membrane element according to claim 1.   A bag-shaped separation membrane is wound around the outer peripheral surface of the perforated hollow tube and has first and second end portions, and back-flow cleaning is performed with a back pressure higher than 0.05 MPa and lower than 0.3 MPa. A method of operating a spiral membrane module in which one or more possible spiral membrane elements are housed in a pressure vessel having a stock solution inlet and a stock solution outlet, wherein the spiral is passed through the stock solution inlet of the pressure vessel during a filtration operation. The stock solution is supplied from the first end of the mold membrane element, and the permeate is taken out from at least one open end of the perforated hollow tube, and from at least one open end of the perforated hollow tube during backflow cleaning By introducing the cleaning liquid and discharging the cleaning liquid from at least one of the first and second ends of the spiral membrane element, the cleaning liquid is higher than 0.05 MPa and higher than 0.3 MPa. The separation membrane is backwashed with a back pressure of Pa or less and contaminated from the second end of the spiral membrane element through the stock solution outlet before the backwashing, during the backwashing or after the backwashing. A stock solution containing a chemical having a substance peeling action or a bactericidal action is introduced, and the stock solution is caused to flow in the spiral membrane element in the direction opposite to that during the filtration operation and led out from the first end of the spiral membrane element. A method for operating the spiral membrane module, wherein the spiral vessel module is taken out through the stock solution inlet of the pressure vessel. One or a plurality of spiral membrane elements, each having a bag-like separation membrane wound around the outer peripheral surface of a perforated hollow tube and capable of back-flow cleaning with a back pressure higher than 0.05 MPa and lower than 0.3 MPa A method for cleaning a spiral membrane module accommodated in a pressure vessel having an inlet and a stock solution outlet, wherein the spiral membrane is introduced by introducing a cleaning solution from at least one open end of the perforated hollow tube during backflow cleaning. By discharging from at least one of the first and second end portions of the element and taking it out of the pressure vessel, the separation membrane is backwashed with a back pressure of 0.05 MPa or more and 0.3 MPa or less, and the backflow Before the cleaning, during the backwashing or after the backwashing, it is possible to remove the contaminant from the second end of the spiral membrane element through the stock solution outlet of the pressure vessel. Introduces a stock solution containing a chemical having a bactericidal action, causes the stock solution to flow in the spiral membrane element in the direction opposite to that during filtration operation, and leads out from the first end of the spiral membrane element, A spiral membrane module cleaning method, characterized in that the spiral membrane module is taken out through the stock solution inlet. A bag-shaped separation membrane is wound around the outer peripheral surface of the perforated hollow tube and has first and second end portions, and back-flow cleaning is performed with a back pressure higher than 0.05 MPa and lower than 0.3 MPa. A method of cleaning a spiral membrane module in which one or more possible spiral membrane elements are housed in a pressure vessel having a stock solution inlet and a stock solution outlet, wherein at least one of the perforated hollow tubes is used during backflow cleaning. By introducing the cleaning liquid from the open end, discharging the cleaning liquid from at least one of the first and second ends of the spiral membrane element and taking it out of the pressure vessel, it is higher than 0.05 MPa and lower than 0.3 MPa. The separation membrane is backwashed with a back pressure of, and before the backwashing, during the backwashing or after the backwashing, the spiral membrane element is passed through the stock solution inlet of the pressure vessel. A cleaning liquid containing a chemical having a pollutant removing action or a sterilizing action is introduced from the first end of the nozzle, and the cleaning liquid containing the chemical is caused to flow in the spiral membrane element in the same direction as during the filtration operation. Deriving from the second end of the mold membrane element, taking out to the outside through the stock solution outlet of the pressure vessel, and contaminating from the second end of the spiral membrane element through the stock solution outlet of the pressure vessel A cleaning liquid containing a chemical having a substance peeling action or a bactericidal action is introduced to flow the cleaning liquid containing the chemical in the spiral type membrane element in a direction opposite to that during the filtration operation, and the first end of the spiral type membrane element. And the operation of taking out from the section through the stock solution inlet of the pressure vessel to the outside is performed in order. Pairaru membrane module cleaning method.

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