JP4082202B2 - Reverse osmosis membrane feed water evaluation method and water treatment device operation management method - Google Patents
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【０００１】
【発明の属する技術分野】
本発明は、逆浸透膜供給水の評価方法及び逆浸透膜装置を含む水処理装置の運転管理方法に関する。詳しくは、本発明は、逆浸透膜の透過流束の低下を招くことなく、長期間にわたって逆浸透膜装置を安定して運転するための逆浸透膜供給水の評価方法と、この評価結果に基づいて水処理装置の運転を適正に管理する方法に関する。
【０００２】
【従来の技術】
逆浸透膜は溶質の阻止率が高いため、逆浸透膜処理により清澄な透過水を得ることができるという優れた利点を有する。しかし、その一方で、処理の継続に伴い膜の透過流束が低下し、操作圧力が上昇するため、この場合には、膜性能を回復させるために、運転を停止して逆浸透膜を洗浄する処理が必要となる。
【０００３】
従来においては、逆浸透膜を用いて水処理を行う場合、このような膜洗浄頻度を低減して、処理効率を高めるために、逆浸透膜装置への供給水を、ＪＩＳ Ｋ３８０２に定義されているファウリングインデックス（ＦＩ）、又はＡＳＴＭ Ｄ４１８９に定義されているシルトデンシティインデックス（ＳＤＩ）や、より簡便な評価方法として谷口により提案されたＭＦ値（Ｄｅｓａｌｉｎａｔｉｏｎ，ｖｏｌ．２０，ｐ．３５３−３６４，１９７７）で評価し、この値が規定値以下となるように必要に応じて前処理を実施し、逆浸透膜供給水をある程度清澄にすることにより、逆浸透膜装置における透過流束の低下や操作圧力の上昇などの障害を避け、安定運転を継続する方法が実施されている。
【０００４】
ＦＩ値、ＳＤＩ値、ＭＦ値はいずれも逆浸透膜供給水を０．４５μｍの精密濾過膜（通常、日本ミリポア株式会社の「ミリポアフィルター」を用いることが多い。）で濾過したときの所定の濾過時間を測定し、この測定値に基いて算出されるものである。従来、これらの評価に用いられているミリポアフィルターは、セルロース系（ニトロセルロースとセルロースアセテートとの混合エステル）メンブレンフィルターである。
【０００５】
【非特許文献１】
Ｄｅｓａｌｉｎａｔｉｏｎ，ｖｏｌ．２０，ｐ．３５３−３６４，
１９７７
【０００６】
【発明が解決しようとする課題】
しかしながら、ＦＩ値又はＳＤＩ値やＭＦ値が規定値以下の逆浸透膜供給水であっても、逆浸透膜において透過流束の低下や操作圧力の上昇が早期に発生する場合があった。
【０００７】
即ち、従来のＦＩ値、ＳＤＩ値又はＭＦ値の評価は、原水中のＳＳを捕捉することにより、これを濾過時間に反映することができるため、ＳＳに基く逆浸透膜供給水としての良否の判定には有効であるが、原水中の溶解性の汚れ成分を濾過時間に反映しない。このため、溶存物質の化学的相互作用に基く逆浸透膜供給水としての良否を的確には判定できない。
【０００８】
このため、逆浸透膜における透過流束の低下、操作圧力の上昇を防ぎ、長期間にわたって安定に運転を継続し、水質の良好な透過水を得ることのできる逆浸透膜供給水の評価方法、及び運転管理方法が求められていた。
【０００９】
本発明は、逆浸透膜の透過流束の低下、操作圧力の上昇を招くことなく、長期間にわたって逆浸透膜装置を安定して運転するための、逆浸透膜供給水の評価方法と、逆浸透膜装置を含む水処理装置の運転管理方法を提供することを目的とする。
【００１０】
【課題を解決するための手段】
本発明の逆浸透膜供給水の評価方法は、逆浸透膜装置に供給される水の逆浸透膜供給水としての良否を評価する方法において、ポリアミド系メンブレンフィルターを用いて逆浸透膜供給水の濾過を継続し、所定量毎の濾過時間を測定し、濾過開始時の濾過時間に対する濾過時間の増加割合を調べ、濾過水量の増加と共に、この所定量毎の濾過時間が増加する水を逆浸透膜供給水としては好ましくないと評価することを特徴とする。
【００１１】
本発明者は、上記課題を解決すべく鋭意研究を重ねた結果、逆浸透膜の透過流束が低下する原因は、原水（逆浸透膜供給水）に含まれる懸濁固形物（ＳＳ）による物理的閉塞作用だけでなく、原水に含まれる溶存物質による化学的相互作用（吸着、イオン結合など）も影響を及ぼすことを知見した。特に、近年、酢酸セルロース系逆浸透膜に代って、主流となってきたポリアミド系逆浸透膜は、脱塩率が高い上に有機物質の除去性にも優れ、界面活性剤等の有機系溶存物質を化学的相互作用により捕捉することもあるため、これらの溶存物質による影響によっても透過流束が低下する。
【００１２】
本発明は、ポリアミド系メンブレンフィルターの特徴を利用して、原水中の溶存物質の化学的相互作用による影響を評価するものである。
【００１３】
本発明の逆浸透膜供給水の評価方法によれば、逆浸透膜供給水をポリアミド系メンブレンフィルターに通水することにより、逆浸透膜供給水中のＳＳによる物理的閉塞作用と溶存物質による化学的相互作用の影響とを十分に評価して逆浸透膜供給水としての良否を的確に判定することができる。
【００１４】
本発明の水処理装置の運転管理方法は、このような本発明の逆浸透膜供給水の評価方法により逆浸透膜供給水の良否を評価し、その結果に基いて、前処理装置の運転条件を変更する、新たな前処理を追加する、又は逆浸透膜装置の洗浄頻度を変更するものであり、的確な評価結果に基いて逆浸透膜装置における透過流束の低下や操作圧力の上昇などの障害を引き起こすことなく、長期にわたり安定な運転を継続することができる。
【００１５】
【発明の実施の形態】
以下に本発明の逆浸透膜供給水の評価方法及び水処理装置の運転管理方法の実施の形態を詳細に説明する。
【００１６】
本発明で用いるポリアミド系メンブレンフィルターの材質や細孔径には特に制限はなく、例えばポリアミド、６ナイロン、６６ナイロンなどよりなり、０．４５μｍ、０．２μｍなどの公称孔径を有するメンブレンフィルターを用いることができる。これらの中でも、ポリアミド系逆浸透膜に近い材質であること、また従来法との比較という観点より、公称孔径０．４５μｍのポリアミド系メンブレンフィルターが好適である。
【００１７】
本発明の評価方法においては、評価に用いるポリアミド系メンブレンフィルターの細孔径よりも小さな細孔径を有する膜を用いて逆浸透膜供給水を前濾過し、逆浸透膜供給水中のＳＳを十分に除去した後、ポリアミド系メンブレンフィルターに通水しても良く、このようにすることにより、逆浸透膜供給水に含まれる溶存物質の化学的相互作用の影響をより一層確実に評価することができる。
【００１８】
この場合、前濾過用の膜の種類や材質に特に制限はなく、例えば種類としては精密濾過膜、限外濾過膜など、材質としてはセルロースアセテート（ＣＡ）、ポリスルホン（ＰＳ）、ポリアクリルニトリル（ＰＡＮ）などを挙げることができる。
【００２０】
本発明においては、後述の実施例のようにポリアミド系メンブレンフィルターを用いて逆浸透膜供給水の濾過を継続し、所定量毎の濾過時間を測定し、濾過開始時の濾過時間に対する濾過時間の増加割合を調べる。
【００２１】
本発明の逆浸透膜供給水の評価方法においては、逆浸透膜供給水をポリアミド系メンブレンフィルターに通水して求めた濾過抵抗（濾過時間）に、従来のＭＦ値と同様に換算係数を乗じ、水温による換算を行うようにしても良い。また、このようにして、逆浸透膜供給水をポリアミド系メンブレンフィルターに通水した際の濾過抵抗を求めると共に、従来法のＦＩ値、ＳＤＩ値、ＭＦ値を求め、これらの結果を併用して評価を行うようにしても良い。
【００２２】
このような本発明の逆浸透膜供給水の評価方法が適用される逆浸透膜の材質に特に制限はなく、例えば、ポリアミド系逆浸透膜、セルロースエステル系逆浸透膜、ポリスルホン系逆浸透膜、ポリイミド系逆浸透膜などを挙げることができる。逆浸透膜の形態にも特に制限はなく。相転換膜、複合膜のいずれにも用いることができる。これらの中で、膜支持体となる限外濾過膜にポリスルホンを用い、緻密層に架橋ポリアミド、線状ポリアミド、ポリピペラジンアミドなどを用いたポリアミド系逆浸透膜を好適に用いることができる。
【００２３】
本発明の逆浸透膜供給水の評価方法が適用される逆浸透膜装置の膜モジュールの種類にも特に制限はなく、例えばスパイラルモジュール、中空糸モジュール、平面膜モジュール、管型モジュールなども挙げることができる。
【００２４】
本発明の水処理装置の運転管理方法においては、このような本発明の逆浸透膜供給水の評価方法により、逆浸透膜供給水をポリアミド系メンブレンフィルターに通水して逆浸透膜供給水の良否を評価し、その結果に基いて逆浸透膜装置を含む水処理装置の運転を管理する。この運転管理方法に特に制限はなく、例えば、前処理装置の運転条件を変更する、新たな前処理を追加する、逆浸透膜装置の洗浄頻度を変更するなどが挙げられる。
【００２５】
【実施例】
以下に、実施例及び比較例を挙げて本発明をより具体的に説明するが、本発明はその要旨を超えない限り、以下の実施例により何ら限定されるものではない。
【００２６】
［評価例１］
実施例１
機械工場の排水処理設備出口水を用いて、試験を実施した。まず、この排水処理設備出口水を、細孔径０．２μｍのカートリッジフィルタ（アドバンテック東洋（株）製「ＴＣＲ０２０」）で精密濾過した。濾過水３Ｌを、直径４７ｍｍ、細孔径０．４５μｍのポリアミド系メンブレンフィルター（ＳａｒｔｏｒｉｕｓＣｏ．製「ＳＡＲＴＯＬＯＮ ＰＯＬＹＡＭＩＤ」）を用い、５００ｍｍＨｇで減圧濾過し、濾過に要する時間を５００ｍＬ毎に、６回に分けて計測した。
【００２７】
０〜０．５Ｌ，０．５〜１Ｌ，１〜１．５Ｌ，１．５〜２Ｌ，２〜２．５Ｌ，２．５〜３Ｌの濾過に要した時間を、それぞれＴ１，Ｔ２，Ｔ３，Ｔ４，Ｔ５，Ｔ６とし、Ｔ１に対するＴ１〜Ｔ６の比をそれぞれＭＦＦ１（＝Ｔ１／Ｔ１），ＭＦＦ２（＝Ｔ２／Ｔ１），ＭＦＦ３（＝Ｔ３／Ｔ１），ＭＦＦ４（＝Ｔ４／Ｔ１），ＭＦＦ５（＝Ｔ５／Ｔ１），ＭＦＦ６（＝Ｔ６／Ｔ１）として評価した。
【００２８】
ＭＦＦ１〜６の値は表１に示す通りであった。
【００２９】
比較例１
実施例１と同じ機械工場の排水処理設備出口水を、実施例１と同様に精密濾過し、濾過水３Ｌを、直径４７ｍｍ、細孔径０．４５μｍのセルロース系メンブレンフィルター（Ｍｉｌｌｉｐｏｒｅ Ｃｏ．製「ミリポアフィルタＨＡＷＰ」）を用いて濾過したこと以外は実施例１と同様にしてＭＦＦ１〜６の値を求めた。
【００３０】
ＭＦＦ１〜６の値は表１に示す通りであった。
【００３１】
【表１】
表１に見られるように、ポリアミド系メンブレンフィルターを用いた場合（実施例１）には、ＭＦＦの値は濾過水量の増加と共に増加したが、従来法であるＭＦ法やＦＩ法で用いられるセルロース系メンブレンフィルターを用いた場合（比較例１）には、ＭＦＦ値は、３Ｌの濾過水量の範囲で、濾過水量が増加してもほぼ一定であった。
【００３３】
実施例１及び比較例１と同じ機械工場の排水処理設備出口水を、実施例１及び比較例１と同様に精密濾過した後、ポリアミド系逆浸透膜（日東電工（株）製「ＮＴＲ７５９ＨＲ」）に２５℃、圧力１．５ＭＰａで通水した。このときの透過流束は図１に示す通りであり、通水開始直後０．７４ｍ／ｄ、２４時間後０．５１ｍ／ｄ、６０時間後０．４６ｍ／ｄであった。
【００３４】
表１及び図１の結果から、次のことが明らかである。
【００３５】
即ち、図１に示す如く、試験に用いた排水処理設備出口水の精密濾過水は、透過流束の経時上昇を引き起こすものであり、逆浸透膜供給水としては好ましくない。しかし、比較例１の従来法ではＭＦＦ値は濾過水量が増加してもほぼ一定であり、この評価方法であれば、この排水処理設備出口水は逆浸透膜供給水としては良好であると評価される。これに対して、ポリアミド系メンブレンフィルターを用いた実施例１の評価方法では、ＭＦＦ値が濾過水量の増加と共に増加するため、この排水処理設備出口水は逆浸透膜供給水として好適ではなく、逆浸透膜装置における透過流束の経時低下が予想される。
【００３６】
［評価例２］
実施例２
実施例１と同じ機械工場の排水処理設備出口水を、粒状活性炭（栗田工業（株）製「ＷＧ１６０ ２０／４２」）を充填したカラムに通水して吸着処理し、その吸着処理水を細孔径０．２μｍのカートリッジフィルタ（アドバンテック東洋（株）製「ＴＣＲ０２０」）で精密濾過した。濾過水３Ｌを、直径４７ｍｍ、細孔径０．４５μｍのポリアミド系メンブレンフィルター（Ｓａｒｔｏｒｉｕｓ Ｃｏ．製「ＳＡＲＴＯＬＯＮ ＰＯＬＹＡＭＩＤ」）を用いて濾過することにより、実施例１と同様にしてＭＦＦ１〜６の値を求めた。
【００３７】
ＭＦＦ１〜６の値は表２に示す通りであった。
【００３８】
比較例２
実施例１と同じ機械工場の排水処理設備出口水を、実施例２と同様に吸着処理及び精密濾過し、濾過水３Ｌを、直径４７ｍｍ、細孔径０．４５μｍのセルロース系メンブレンフィルター（Ｍｉｌｌｉｐｏｒｅ Ｃｏ．製「ミリポアフィルタＨＡＷＰ」）を用いて濾過したこと以外は実施例１と同様にしてＭＦＦ１〜６の値を求めた。
【００３９】
ＭＦＦ１〜６の値は表２に示す通りであった。
【００４０】
【表２】
表２に見られるように、ポリアミド系メンブレンフィルターを用いた場合（実施例２）も、従来法であるＭＦ法やＦＩ法で用いられるセルロース系メンブレンフィルターを用いた場合（比較例２）も、ＭＦＦの値はいずれも３Ｌの濾過水量の範囲で、濾過水量が増加してもほぼ一定であった。ただし、ポリアミド系メンブレンフィルターを用いた実施例２では、ＭＦＦ値のわずかな増加が認められる。
【００４２】
実施例２及び比較例２と同じ機械工場の排水処理設備出口水を実施例２及び比較例２と同様に吸着処理及び精密濾過した後、ポリアミド系逆浸透膜（日東電工（株）製「ＮＴＲ７５９ＨＲ」）に２５℃、圧力１．５ＭＰａで通水した。このときの透過流束は図１に示す通りであり、通水開始直後１．０７ｍ／ｄ、２４時間後０．９４ｍ／ｄ、６０時間後０．９２ｍ／ｄであった。
【００４３】
表２及び図１の結果から、次のことが明らかである。
【００４４】
即ち、図１に示す如く、試験に用いた排水処理設備出口水の活性炭吸着及び精密濾過水は、透過流束の経時上昇の小さいものであり、逆浸透膜供給水としては比較的好ましいものである。これに対して、実施例２でも比較例２でもＭＦＦ値は濾過水量が増加してもほぼ一定であり、いずれも逆浸透膜供給水として好適であるとの評価結果となる。ただし、実施例２においては、濾過水量の増加と共にＭＦＦ値がわずかに増加しており、この結果から、図１における透過水量の若干の経時低下を予測することができる。
【００４５】
【発明の効果】
以上詳述した通り、本発明の逆浸透膜供給水の評価方法によれば、逆浸透膜供給水をポリアミド系メンブレンフィルターを用いて評価することにより、逆浸透膜供給水としての良否を的確に評価することができる。そして、このようなポリアミド系メンブレンフィルターを用いた評価結果に基いて運転管理を行う本発明の水処理装置の運転管理方法によれば、逆浸透膜装置において高透過流束を維持することができ、長期にわたり安定した運転を継続することができる。
【図面の簡単な説明】
【図１】実施例１，２及び比較例１，２における逆浸透膜装置の透過流束の経時変化を示すグラフである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reverse osmosis membrane feed water evaluation method and a water treatment device operation management method including a reverse osmosis membrane device. Specifically, the present invention relates to an evaluation method of reverse osmosis membrane feed water for stably operating a reverse osmosis membrane device over a long period of time without causing a decrease in the permeation flux of the reverse osmosis membrane, and to this evaluation result. The present invention relates to a method for appropriately managing the operation of a water treatment apparatus based on the above.
[0002]
[Prior art]
Since the reverse osmosis membrane has a high solute rejection rate, it has an excellent advantage that a clear permeate can be obtained by the reverse osmosis membrane treatment. However, on the other hand, the permeation flux of the membrane decreases with the continuation of the process and the operating pressure increases. In this case, the operation is stopped and the reverse osmosis membrane is washed to restore the membrane performance. It is necessary to perform processing.
[0003]
Conventionally, when water treatment is performed using a reverse osmosis membrane, the supply water to the reverse osmosis membrane device is defined in JIS K3802 in order to reduce the frequency of membrane washing and increase the treatment efficiency. Fouling index (FI), silt density index (SDI) defined in ASTM D4189, or MF value proposed by Taniguchi as a simpler evaluation method (Desalination, vol. 20, p.353-364) 1977), pretreatment is carried out as necessary so that this value is not more than the specified value, and the osmosis flux in the reverse osmosis membrane device is reduced by clarifying the reverse osmosis membrane feed water to some extent. A method has been implemented in which stable operation is avoided while avoiding obstacles such as an increase in operating pressure.
[0004]
The FI value, SDI value, and MF value are all determined when the reverse osmosis membrane feed water is filtered through a 0.45 μm microfiltration membrane (usually, a “Millipore filter” manufactured by Nihon Millipore Corporation is often used). The filtration time is measured and calculated based on this measured value. Conventionally, the Millipore filter used for these evaluations is a cellulosic (mixed ester of nitrocellulose and cellulose acetate) membrane filter.
[0005]
[Non-Patent Document 1]
Desalination, vol. 20, p. 353-364
1977
[0006]
[Problems to be solved by the invention]
However, even if the reverse osmosis membrane supply water has an FI value, an SDI value, or an MF value equal to or less than a specified value, a decrease in permeation flux or an increase in operating pressure may occur at an early stage in the reverse osmosis membrane.
[0007]
That is, since the conventional evaluation of FI value, SDI value or MF value can be reflected in the filtration time by capturing SS in raw water, the quality of reverse osmosis membrane supply water based on SS Although effective for determination, it does not reflect soluble soil components in raw water in the filtration time. For this reason, the quality as reverse osmosis membrane supply water based on the chemical interaction of dissolved substances cannot be accurately determined.
[0008]
For this reason, a decrease in the permeation flux in the reverse osmosis membrane, an increase in operating pressure, a stable operation over a long period of time, and a reverse osmosis membrane feed water evaluation method that can obtain a permeated water with good water quality, In addition, an operation management method has been demanded.
[0009]
The present invention relates to a method for evaluating reverse osmosis membrane feed water for stable operation of a reverse osmosis membrane device over a long period of time without causing a decrease in the permeation flux of the reverse osmosis membrane and an increase in operating pressure. It aims at providing the operation management method of the water treatment equipment containing an osmosis membrane device.
[0010]
[Means for Solving the Problems]
Evaluation method of reverse osmosis membrane supply water of the present invention is a method of evaluating the quality of the reverse osmosis membrane supply water of the water supplied to the reverse osmosis unit, a reverse osmosis membrane supply water using the polyamides based membrane filter The filtration time for each predetermined amount is measured, the increase rate of the filtration time with respect to the filtration time at the start of filtration is examined, and the water whose filtration time increases for each predetermined amount is reversed as the amount of filtered water increases. It is characterized by evaluating that it is not preferable as osmosis membrane supply water .
[0011]
As a result of intensive studies to solve the above-mentioned problems, the present inventor is responsible for the decrease in the permeation flux of the reverse osmosis membrane due to the suspended solids (SS) contained in the raw water (reverse osmosis membrane feed water). It was found that not only physical clogging but also chemical interaction (adsorption, ionic bonding, etc.) caused by dissolved substances contained in raw water. In particular, in recent years, polyamide-based reverse osmosis membranes, which have become the mainstream in place of cellulose acetate-based reverse osmosis membranes, have a high desalting rate and excellent organic substance removability. Since dissolved substances may be trapped by chemical interaction, the permeation flux decreases due to the influence of these dissolved substances.
[0012]
This invention evaluates the influence by the chemical interaction of the dissolved substance in raw | natural water using the characteristic of a polyamide-type membrane filter.
[0013]
According to the reverse osmosis membrane feed water evaluation method of the present invention, by passing the reverse osmosis membrane feed water through the polyamide membrane filter, the physical blockage action by the SS in the reverse osmosis membrane feed water and the chemical by the dissolved substance The quality of the reverse osmosis membrane supply water can be accurately determined by sufficiently evaluating the influence of the interaction.
[0014]
The operation management method of the water treatment apparatus of the present invention evaluates the quality of the reverse osmosis membrane supply water by the reverse osmosis membrane supply water evaluation method of the present invention, and based on the result, the operating conditions of the pretreatment apparatus , Change the cleaning frequency of the reverse osmosis membrane device, decrease the permeation flux in the reverse osmosis membrane device, increase the operating pressure, etc. It is possible to continue stable operation for a long time without causing any trouble.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of an evaluation method for reverse osmosis membrane feed water and an operation management method for a water treatment apparatus according to the present invention will be described in detail below.
[0016]
The material and pore diameter of the polyamide membrane filter used in the present invention are not particularly limited. For example, a membrane filter made of polyamide, 6 nylon, 66 nylon or the like and having a nominal pore diameter of 0.45 μm, 0.2 μm or the like is used. Can do. Among these, a polyamide membrane filter having a nominal pore diameter of 0.45 μm is preferable from the viewpoint of being a material close to a polyamide-based reverse osmosis membrane and comparing with a conventional method.
[0017]
In the evaluation method of the present invention, the reverse osmosis membrane feed water is prefiltered using a membrane having a pore size smaller than the pore size of the polyamide membrane filter used for the evaluation, and SS in the reverse osmosis membrane feed water is sufficiently removed. After that, water may be passed through the polyamide membrane filter. By doing so, the influence of chemical interaction of dissolved substances contained in the reverse osmosis membrane feed water can be more reliably evaluated.
[0018]
In this case, there are no particular limitations on the type and material of the prefiltration membrane. For example, the type is a microfiltration membrane, an ultrafiltration membrane, etc., and the materials are cellulose acetate (CA), polysulfone (PS), polyacrylonitrile ( PAN).
[0020]
In the present invention, the filtration of the reverse osmosis membrane feed water is continued using a polyamide membrane filter as in the examples described later, the filtration time for each predetermined amount is measured, and the filtration time relative to the filtration time at the start of filtration is Ru examine the rate of increase.
[0021]
In the reverse osmosis membrane feed water evaluation method of the present invention, the filtration resistance (filtration time) obtained by passing the reverse osmosis membrane feed water through a polyamide membrane filter is multiplied by a conversion factor as in the conventional MF value. The conversion by the water temperature may be performed. In addition, in this way, the filtration resistance when the reverse osmosis membrane feed water is passed through the polyamide membrane filter is obtained, and the FI value, SDI value, and MF value of the conventional method are obtained, and these results are used in combination. An evaluation may be performed.
[0022]
There is no particular limitation on the material of the reverse osmosis membrane to which the evaluation method of the reverse osmosis membrane supply water of the present invention is applied, for example, polyamide-based reverse osmosis membrane, cellulose ester-based reverse osmosis membrane, polysulfone-based reverse osmosis membrane, Examples thereof include a polyimide-based reverse osmosis membrane. There is no particular limitation on the form of the reverse osmosis membrane. It can be used for both phase change membranes and composite membranes. Among these, a polyamide-based reverse osmosis membrane using polysulfone as an ultrafiltration membrane serving as a membrane support and using a crosslinked polyamide, linear polyamide, polypiperazine amide or the like as a dense layer can be suitably used.
[0023]
The type of membrane module of the reverse osmosis membrane device to which the method for evaluating the reverse osmosis membrane supply water of the present invention is applied is not particularly limited, and examples include a spiral module, a hollow fiber module, a planar membrane module, and a tubular module. Can do.
[0024]
In the operation management method of the water treatment apparatus of the present invention, the reverse osmosis membrane feed water is passed through the polyamide membrane filter by the reverse osmosis membrane feed water evaluation method of the present invention. The quality is evaluated and the operation of the water treatment apparatus including the reverse osmosis membrane apparatus is managed based on the result. The operation management method is not particularly limited, and examples thereof include changing the operating conditions of the pretreatment device, adding a new pretreatment, and changing the cleaning frequency of the reverse osmosis membrane device.
[0025]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the following examples unless it exceeds the gist.
[0026]
[Evaluation Example 1]
Example 1
The test was carried out using the water discharged from the waste water treatment facility of the machine factory. First, the water discharged from the wastewater treatment facility was microfiltered with a cartridge filter having a pore diameter of 0.2 μm (“TCR020” manufactured by Advantech Toyo Co., Ltd.). 3 L of filtered water was filtered under reduced pressure at 500 mmHg using a polyamide membrane filter (Sartorius Co. “SARTOLON POLYAMID”) having a diameter of 47 mm and a pore diameter of 0.45 μm, and the time required for filtration was divided into 6 times every 500 mL. Measured.
[0027]
The time required for the filtration of 0 to 0.5 L, 0.5 to 1 L, 1 to 1.5 L, 1.5 to 2 L, 2 to 2.5 L, and 2.5 to 3 L is expressed as T1, T2, T3, respectively. T4, T5, and T6, and the ratios of T1 to T6 with respect to T1 are MFF1 (= T1 / T1), MFF2 (= T2 / T1), MFF3 (= T3 / T1), MFF4 (= T4 / T1), and MFF5 ( = T5 / T1) and MFF6 (= T6 / T1).
[0028]
The values of MFF1 to 6 were as shown in Table 1.
[0029]
Comparative Example 1
The outlet water of the wastewater treatment facility in the same machine factory as in Example 1 was subjected to microfiltration in the same manner as in Example 1, and 3 L of filtered water was obtained from a cellulose membrane filter (Millipore Co. “Millipore Co., Ltd.” having a diameter of 47 mm and a pore diameter of 0.45 μm). The values of MFF 1 to 6 were obtained in the same manner as in Example 1 except that the filtration was performed using the filter HAWP ”).
[0030]
The values of MFF1 to 6 were as shown in Table 1.
[0031]
[Table 1]
As can be seen from Table 1, when a polyamide membrane filter was used (Example 1), the MFF value increased with the increase in the amount of filtered water, but cellulose used in the conventional MF method and FI method. When the system membrane filter was used (Comparative Example 1), the MFF value was in the range of 3 L of filtered water volume, and was almost constant even when the filtered water volume increased.
[0033]
After draining the waste water treatment facility outlet water of the same machine factory as in Example 1 and Comparative Example 1 in the same manner as in Example 1 and Comparative Example 1, polyamide-based reverse osmosis membrane (“NTR759HR” manufactured by Nitto Denko Corporation) The water was passed through at 25 ° C. and a pressure of 1.5 MPa. The permeation flux at this time was as shown in FIG. 1 and was 0.74 m / d immediately after the start of water flow, 0.51 m / d after 24 hours, and 0.46 m / d after 60 hours.
[0034]
From the results shown in Table 1 and FIG.
[0035]
That is, as shown in FIG. 1, the precision filtered water of the wastewater treatment facility outlet water used in the test causes an increase in permeation flux over time, and is not preferable as reverse osmosis membrane supply water. However, in the conventional method of Comparative Example 1, the MFF value is substantially constant even when the amount of filtered water increases, and with this evaluation method, it is evaluated that the wastewater treatment facility outlet water is good as reverse osmosis membrane supply water. Is done. On the other hand, in the evaluation method of Example 1 using a polyamide-based membrane filter, the MFF value increases with an increase in the amount of filtered water, so this wastewater treatment facility outlet water is not suitable as reverse osmosis membrane supply water. It is expected that the permeation flux in the osmotic membrane device will decrease with time.
[0036]
[Evaluation Example 2]
Example 2
Waste water treatment facility outlet water of the same machine factory as in Example 1 is subjected to adsorption treatment by passing it through a column packed with granular activated carbon (“
[0037]
The values of MFF1 to 6 were as shown in Table 2.
[0038]
Comparative Example 2
The waste water treatment facility outlet water of the same machine factory as in Example 1 was subjected to adsorption treatment and microfiltration in the same manner as in Example 2, and 3 L of filtered water was a cellulose membrane filter (Millipore Co., Ltd.) having a diameter of 47 mm and a pore diameter of 0.45 μm. The value of MFF1-6 was calculated | required like Example 1 except having filtered using "Millipore filter HAWP" made from a product.
[0039]
The values of MFF1 to 6 were as shown in Table 2.
[0040]
[Table 2]
As can be seen in Table 2, both when using a polyamide membrane filter (Example 2) and when using a cellulose membrane filter used in the conventional MF method and FI method (Comparative Example 2), The values of MFF were all in the range of 3 L of filtered water, and were almost constant even when the amount of filtered water increased. However, in Example 2 using a polyamide membrane filter, a slight increase in the MFF value is observed.
[0042]
The wastewater treatment facility outlet water of the same machine factory as in Example 2 and Comparative Example 2 was subjected to adsorption treatment and microfiltration in the same manner as in Example 2 and Comparative Example 2, and then a polyamide-based reverse osmosis membrane (“NTR759HR manufactured by Nitto Denko Corporation”). )) At 25 ° C. and a pressure of 1.5 MPa. The permeation flux at this time was as shown in FIG. 1 and was 1.07 m / d immediately after the start of water flow, 0.94 m / d after 24 hours, and 0.92 m / d after 60 hours.
[0043]
From the results of Table 2 and FIG. 1, the following is clear.
[0044]
That is, as shown in FIG. 1, the activated carbon adsorption and microfiltration water of the wastewater treatment facility outlet water used in the test has a small increase in permeation flux over time, and is relatively preferable as reverse osmosis membrane supply water. is there. On the other hand, in both Example 2 and Comparative Example 2, the MFF value is substantially constant even when the amount of filtered water increases, and both are evaluation results that are suitable as reverse osmosis membrane supply water. However, in Example 2, the MFF value slightly increased with the increase in the amount of filtered water, and from this result, a slight decrease in the amount of permeated water in FIG. 1 with time can be predicted.
[0045]
【The invention's effect】
As described above in detail, according to the evaluation method of reverse osmosis membrane supply water of the present invention, the quality of reverse osmosis membrane supply water is accurately determined by evaluating reverse osmosis membrane supply water using a polyamide membrane filter. Can be evaluated. And according to the operation management method of the water treatment apparatus of the present invention that performs operation management based on the evaluation result using such a polyamide-based membrane filter, a high permeation flux can be maintained in the reverse osmosis membrane apparatus. , Stable operation can be continued for a long time.
[Brief description of the drawings]
FIG. 1 is a graph showing changes with time in permeation fluxes of reverse osmosis membrane devices in Examples 1 and 2 and Comparative Examples 1 and 2. FIG.
Claims (3)
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