JP3644119B2

JP3644119B2 - Membrane filtration device and membrane filtration method

Info

Publication number: JP3644119B2
Application number: JP05467196A
Authority: JP
Inventors: 博嗣土屋; 健一郎水野; 辰夫武智; 佳秀蔭山
Original assignee: JFE Engineering Corp
Current assignee: JFE Engineering Corp
Priority date: 1996-03-12
Filing date: 1996-03-12
Publication date: 2005-04-27
Anticipated expiration: 2016-03-12
Also published as: JPH09248572A

Description

【０００１】
【発明の属する技術分野】
本発明は、表流水、伏流水、地下水等の上水処理、工水処理、排水処理等の水処理分野において溶解性物質及び不溶解性の懸濁物質を除去するために用いられる膜濾過装置及びその膜濾過方法に関するものである。
【０００２】
【従来の技術】
一般に、水処理に於いては、凝集、沈殿、砂濾過等によってなされ、通常の水処理では除去できない異臭味原因物質、合成洗剤、フェノール類、農薬等の溶解性物質は、粉末と粒状の活性炭によって除去されている。
【０００３】
近年、水処理は、凝集、沈殿、砂濾過の代わりに膜濾過が用いられるようになっている。膜濾過は砂濾過と比較して一定粒径以上の懸濁物は確実に除去できるので、砂濾過による水処理よりも水質が優れているが、膜濾過は懸濁物が除去できるものの溶解性物質は除去できない欠点がある。
【０００４】
このような問題を改善する方法として、水処理に於いて、膜濾過処理と活性炭処理とを組み合わせることによって、懸濁物質が除去できるとともに、溶解性物質をも確実に除去することができる。このような観点から最近の水処理方法では、膜濾過前の処理水に粉末活性炭を注入して溶解性物質を吸着した後に、粉末活性炭を含む処理水を膜濾過処理を行って、懸濁物質とともに溶解性物質が吸着した粉末活性炭を除去する処理方式がなされている。
【０００５】
このような膜濾過処理と活性炭処理とを組み合わせた水処理装置としては、例えば、▲１▼特開平５−１５４４７０号公報、▲２▼特開平６−５５０４６号公報、及び▲３▼特開平６−２２６２９４号公報等に開示されており、以下、図面を参照して順次説明する。
【０００６】
図５は、▲１▼特開平５−１５４４７０号公報に開示された膜濾過装置である。同図に於いて、原水１が原水槽１９に供給され、活性炭注入装置４から粉末活性炭が原水槽１９内に投入される。原水槽１９内の原水１中に投入された粉末活性炭は攪拌装置１８で攪拌混合され、粉末活性炭により溶解性物質が吸着される。原水槽１９の原水は、ポンプ１７を作動させて膜モジュール７から吸引される。原水に混合される活性炭は膜モジュール７で阻止されて、濾過水が処理水槽１４に流出する。膜モジュール７は、濾過に伴って閉塞するために、空気をブロアにより散気装置２１に送り込み、膜モジュール７の膜面に気泡を吹き付けて物理洗浄する。飽和活性炭や汚泥は排泥弁２０から装置外に排出される。
【０００７】
次に、▲２▼特開平６−５５０４６号公報に開示された膜濾過装置について、図６を参照して説明する。同図に於いて、原水１は、原水１中の夾雑物を前処理フィルタ設備（オートストナ）２で除去して原水槽（循環水槽）５に供給され、且つ活性炭注入装置４から粉末活性炭が原水槽５に注入される。循環ポンプ６が作動して、膜濾過装置（膜モジュール）７の膜表面に活性炭、膜分離物質及びスケール（水垢）が除去され、濾過液は処理水槽１４に回収される。使用済活性炭（利用可能活性炭を含む）及びスケール等は配管８を経て循環水槽５に戻され、膜モジュール７の膜面に付着した使用済活性炭（利用可能活性炭を含む）及びスケールは間欠的に配管１１を介して間欠的に装置外に排出される。
【０００８】
続いて、▲３▼特開平６−２２６２９４号公報等に開示された浄水の高度処理装置について、図７を参照して説明する。原水１中の塵等の固形物は除去され、粉末活性炭注入装置４から粉末活性炭を注入して原水槽（生物反応槽）５に供給される。オゾン化空気がオゾン化空気導入管２１を介して散気管２４から生物反応槽５内に供給される。生物反応槽５で処理された水は、膜モジュール（膜分離装置）７に導入され、膜分離装置７によって濾過された濾過水には塩素注入管２５から塩素が注入され、処理水槽へと回収される。粉末活性炭及び生物処理汚泥は配管８から引き抜き抜かれて濃縮槽２２に導入され、上澄水は配管２３を介して生物反応槽５に戻される。
【０００９】
【発明が解決しようとする課題】
しかしながら、図５の膜濾過装置は、原水槽１９に粉末活性炭を注入して吸着能力がなくなるまで、原水と活性炭とを攪拌，混合させた後に、主に溶解性物質が除去される。しかし、原水中の不溶解物質は原水槽１９に沈殿する。不溶解物質の濃度が低い場合は問題はないが、濃度が高い場合は粉末活性炭と汚泥成分（懸濁物質）を分離して汚泥成分のみを排出することが望ましい。しかし、図５に排泥弁２０を介して排出することが開示されているが、その分離方法は明確に記載されていない。排泥弁２０を介して汚泥成分が排出される際に、粉末活性炭も同時に排出され、原水に混入する溶解性物質の除去効率を悪化させるおそれがある。
【００１０】
又、図６の膜濾過装置は、使用済み活性炭、膜分離物質及びスケール等が配管１１を介して装置外に排出されているが、使用済み活性炭であるか否かは区別できない欠点がある。従って、実際には吸着能力がある活性炭が再利用されることなく、装置外に排出される欠点がある。
【００１１】
又、図７の浄水の高度処理装置は、濃縮槽２２で活性炭及び懸濁物質を沈殿させて上澄水のみが生物反応槽５に戻されている。濃縮槽２２で汚泥濃度は高くして装置外に排出されている。しかし、図６の膜濾過装置と同様に使用済み活性炭であるか否かを区別することは困難であり、利用可能な活性炭が再利用されることなく、装置外に排出される欠点がある。
【００１２】
本発明は、上述のような問題点に鑑みなされたものであり、粒状活性炭又は粉末活性炭による活性炭処理と膜濾過処理とを組み合わせて原水中の溶解性物質及び不溶解性の懸濁物質を除去するに当たって、活性炭処理に利用される活性炭を有効に活用して活性炭による水処理効率を向上させた膜濾過装置及び膜濾過方法を提供することを目的とするものである。
又、本発明は、活性炭処理と膜濾過処理とを組み合わせて水処理を行う際の活性炭の消費量を低減して、水処理費用を低減した膜濾過装置及び膜濾過方法を提供することを目的とするものである。
【００１３】
【課題を解決するための手段】
本発明は、上記課題を達成するためになされたものであり、請求項１の発明は、原水を濾過する膜濾過方法に於いて、原水中に含まれる所定サイズ以上の固形物を前処理フィルタで除去し、その処理水に前記サイズ以上の粒径の粒状活性炭又は粉末活性炭を注入し、活性炭と懸濁物質を膜濾過設備によって濾過して濾過水を得るとともに、前記膜濾過設備の膜面に付着した懸濁物質及び活性炭を物理洗浄水によって除去し、前記前処理フィルタの孔径と略等しいかそれ以上の孔径の排水処理用フィルタで前記物理洗浄水を濾過して排出し、前記排水処理用フィルタで阻止した活性炭を前記膜濾過設備の前に返送することを特徴とする膜濾過方法である。
【００１４】
又、請求項２の発明は、請求項１に記載の膜濾過方法に於いて、前記活性炭を注入した後の処理水を原水槽に滞留させることを特徴とする膜濾過方法である。
又、請求項３の発明は、請求項２に記載の膜濾過方法に於いて、前記原水槽に活性炭流動床を設けて前記処理水を滞留させることを特徴とする膜濾過方法である。
又、請求項４の発明は、請求項１乃至３の何れかに記載の膜濾過方法に於いて、注入する活性炭或いは活性炭流動床に用いる活性炭の粒径が１０μｍ以上であることを特徴とする膜濾過方法である。
【００１５】
又、請求項５の発明は、原水を濾過する膜濾過装置に於いて、
原水中に含まれる所定サイズ以上の固形物を除去する前処理フィルタ設備と、前記前処理フィルタ設備で除去される固形物以上の粒径を有する粒状活性炭又は粉末活性炭を注入する活性炭注入設備と、
前記活性炭とともに懸濁物質を除去できる膜濾過設備と、
前記膜濾過設備の膜面に付着した懸濁物質及び活性炭を物理洗浄水によって前記膜面から除去する物理洗浄手段と、
前記物理洗浄手段によって除去した懸濁物質と活性炭の内、所定サイズ以上の活性炭を阻止して前記膜濾過設備の前に返送する排水処理用フィルタ設備と、
を備えることを特徴とする膜濾過装置である。
【００１６】
又、請求項６の発明は、原水を濾過する膜濾過装置に於いて、
原水中に含まれる所定サイズ以上の固形物を除去する前処理フィルタ設備と、
前記前処理フィルタ設備によって処理した処理水を滞留させる原水槽と、
前記原水槽内に備えられた活性炭流動床と、
前記前処理フィルタ設備で除去される固形物以上の粒径を有する粒状活性炭又は粉末活性炭を前記活性炭流動床に供給する活性炭注入設備と、
前記活性炭とともに懸濁物質を除去する膜濾過設備と、
前記膜濾過設備の膜面に付着した懸濁物質及び活性炭を物理洗浄水によって物理洗浄する物理洗浄手段と、
前記物理洗浄手段によって除去した懸濁物質及び活性炭の内、所定のサイズ以上の活性炭を阻止して前記原水槽に返送するための排水処理用フィルタ設備と、
を具備することを特徴とする膜濾過装置である。
【００１７】
【発明の実施の形態】
以下、本発明の一実施形態を図面を参照して説明する。
図１は、本発明に係る膜濾過装置の一実施形態を示す概略図である。同図に於いて、膜濾過装置は、前処理フィルタ設備２、活性炭注入装置４、原水槽５、循環用ポンプ６、膜濾過設備（以下、膜モジュール）７、排水用フィルタ設備１０、処理水槽１４、及び洗浄用ポンプ１３からなり、膜モジュール７と原水槽５との間に濃縮水を原水槽５に返送する返送管８と、膜モジュール７の膜面に付着した活性炭等を物理洗浄水とともに排水用フィルタ設備１０に送水する送水管９と、排水用フィルタ設備１０の膜面に付着する活性炭を原水槽５に返送する活性炭返送管１２と、粒子が磨耗した不要の活性炭、溶解性物質及び不溶解性の懸濁物質を装置外に排出する排水管１１とが設けられている。これらの配管には必要に応じてバルブが設けられる。この膜濾過装置は、処理水槽１４の濾過水が洗浄用ポンプ１３によって膜モジュール７に送り込み、膜モジュール７の膜面に付着する活性炭、溶解性物質及び不溶解性の懸濁物質を除去する物理洗浄用設備が設けられている。
【００１８】
次に、上記各設備等について詳細に説明する。
前処理フィルタ設備２は、網の目状のスクリーンや人工的に開口を設けたもの、或いは、板を所定の間隔で積層させて、その間隔を一定間隔に維持するフィルタが用いられ、原水に含まれる数十μｍ以上の固形物を除去し得る設備である。又、原水中の重力沈降する固形物は、前処理フィルタ設備２の底部に設けられたドレン３を介して排出される。通常、フィルタは数百μｍの孔径が設けられたものが用いられるが、前処理フィルタ設備２を通過した処理水に注入される活性炭の粒径より大きい固形物を除去できるものであればよく、フィルタの孔径は活性炭の粒径より小さいものでなければならない。
【００１９】
活性炭注入装置４は、前処理フィルタ設備２の濾過膜を通過した原水に活性炭を注入する設備であり、一旦一定量の活性炭を注入した後は、活性炭の処理能力が低下して装置外に排出された分を補充し、活性炭を常時注入する必要はない。なお、この実施形態では前処理フィルタ設備２による処理後に活性炭を注入しているが、その実施形態に限定することなく、活性炭は何れの場所に注入してもよい。例えば、原水が供給される原水槽５に直接活性炭を供給してもよい。又、原水槽５内に活性炭流動床が設けられている場合は、図３で詳細に説明するが、活性炭注入装置４から活性炭の流出分を補充すればよい。又、この流出活性炭を積極的に利用して、配管内を流動させた混合流動活性炭によって溶解物質を吸着させ、活性炭が磨耗して所定サイズ以下になると排出用フィルタ装置１０の膜を擦り抜けて装置外に排出される。
【００２０】
原水槽５は、原水を一旦貯留して、活性炭と原水とを十分に混合させてある程度の時間滞留させることにより、活性炭と原水とを十分に混合させる機能を有する。図示されていないが、原水槽５内に攪拌装置を設けて処理水と活性炭とを十分に混合させてもよい。又、原水を活性炭処理する際は、原水が活性炭と十分に混合するある程度の滞留時間が必要であり、活性炭が注入される配管の長さが滞留時間を維持できる程度に存在すれば、必ずしも原水槽５を用いる必要はない。無論、原水の水質によっても滞留時間は異なるが、５〜３０分程度維持される必要がある。原水槽を用いない実施形態については、図２を参照して説明する。
【００２１】
膜モジュール７は、濾過膜（フィルタ）が設けられ、原水槽５の原水が循環用ポンプ６を介して送り込まれ、原水中の活性炭及び懸濁物質が濾過膜により濾過され、濾過水は処理水槽１４に送られる。一方、処理水槽１４の濾過水は種々の用途に利用される。又、濾過水は膜モジュール７に供給して、膜モジュール７の濾過膜の表面に付着する活性炭と懸濁物質を除去する洗浄水としても用いられる。膜モジュール７の濾過膜は、合成繊維、ガラス、樹脂、セラミックス等の素材による膜が用いられ、膜の形状は、管状膜、マルチルーメン膜、平膜等の全てが適用できる。膜の種類としては、精密濾過膜、限外濾過膜、逆浸透膜等の何れでもよい。この濾過膜の孔径は、活性炭と懸濁物質を阻止できる孔径であり、一般的には０．４μｍ以下である。
【００２２】
洗浄用ポンプ１３は、処理水槽１４の濾過水を物理洗浄水として膜モジュール７に供給し、膜モジュール７の濾過膜裏面に水圧を加えることによって、濾過膜に付着する懸濁物質と活性炭をこの物理洗浄水で剥離して、送水管９を介して排水処理用フィルタ装置１０に送られる。膜モジュール７の濾過膜は、物理洗浄時、濾過時とは逆の圧力が加えられ、排水処理用フィルタ装置１０のフィルタにも所定の水圧が加えられる。なお、膜モジュール７の濾過膜に付着する懸濁物質と活性炭の除去は、先に説明したように、濾過膜裏面に物理洗浄水を加える逆圧洗浄手段▲１▼と、他に濾過膜面に気泡を吹き付ける空気剥離手段（エアースクラビ
ング）▲２▼、高圧空気による逆圧洗浄▲３▼等がある。何れの洗浄方法によってもよいが、濾過膜から剥離した懸濁物質と活性炭を排水処理用フィルタ１０に送る必要があり、空気剥離手段や高圧空気による逆圧洗浄の場合にも同時に濾過水を洗浄用ポンプ１３、或いは、空気剥離手段▲２▼又は逆圧洗浄▲３▼の場合はポンプ６によってフィルタ１０に送る。
【００２３】
排水処理用フィルタ設備１０は、送水管９を介して送り込まれる物理洗浄水に混入する活性炭等をフィルタで阻止して、阻止した活性炭等を活性炭返送管１２を介して原水槽５に戻して再利用するための設備である。排水処理用フィルタ設備１０の排水処理用フィルタの孔径は、原水槽５の前段に備えられた前処理フィルタ設備２のフィルタの孔径と略等しい孔径か、それ以下である必要がある。処理水槽１４からの濾過水を洗浄用ポンプ１３によって膜モジュール７に送り、この物理洗浄水を膜モジュール７の濾過膜に通過させて、送水管９を介して排水処理用フィルタ設備１０に送られる。活性炭が除去された洗浄水は排水管１１を介して排出される。
【００２４】
続いて、図１の実施形態による膜濾過処理と膜濾過の逆洗浄工程についてその処理工程に従って説明する。先ず、膜濾過処理について説明すると、原水１は前処理フィルタ設備２に供給され、前処理フィルタ設備２で一定サイズ以上の固形物を除去した後、活性炭注入装置４から前処理フィルタ設備２のサイズ以上の粒径の粒状活性炭又は粉末活性炭が注入される。原水中のアンモニア、トリハロメタン、農薬等の溶解物質がこれらの活性炭に吸着される。これらの活性炭と原水中の懸濁物質は循環用ポンプ６によって膜モジュール７に送られ、膜モジュール７の膜濾過により濾過され、濾過水は処理水槽１４に送られる。
【００２５】
次に、膜濾過の逆洗浄工程について説明すると、処理水槽１４の濾過水は、物理洗浄水として洗浄用ポンプ１３で膜モジュール７の濾過膜の裏面側に送り込まれ、この物理洗浄水による水圧によって濾過膜の表面側に付着する懸濁物質及び活性炭が剥離される。濾過膜には、濾過処理時とは逆に水圧が加えられ、所謂逆圧洗浄が行われる。剥離された懸濁物質や活性炭は物理洗浄排水とともに送水管９を介して排水処理用フィルタ設備１０に送り込まれる。排水処理用フィルタ設備１０では、一定サイズの孔径を有する濾過膜（排水処理用フィルタ）で濾過され、濾過膜を通過した懸濁物質は排水管１１を介して装置外に除去されるとともに、フィルタで阻止された一定サイズ以上の粒状活性炭又は粉末活性炭は返送管１２を介して原水槽５に送り込まれる。活性炭は、原水槽５、膜モジュール７、排水処理用フィルタ設備１０の経路を循環して、濾過洗浄系内に保持される。活性炭は、吸着能力がなくなるまで循環して利用され、活性炭が磨耗して吸着能力がなくなると、排水処理用フィルタ設備１０を介して活性炭と懸濁物質は排水管１１を介して装置外に排出され、膜濾過装置系内、特に原水槽５に汚泥が蓄積するのを防止できる。無論、図示されていないが沈殿物は原水槽５のドレンから排出される。
【００２６】
次に、本発明の膜濾過装置の他の実施形態について、図２の概略図を参照して説明する。なお、図２に於いて、図１と同一部分には同一符号が付与され、同一部分の説明は省略する。
同図に於いて、図１の原水槽５に代えて、前処理フィルタ設備２と循環用ポンプ６間に活性炭が流動する混合流動配管１５が設けられている。活性炭注入設備４は混合流動配管１５の原水の流入側に接続され、活性炭注入設備４から粒状活性炭及び粉末活性炭が混合流動配管１５に注入され、原水中の溶解物質を十分に吸着し得るに、十分な管長を有する混合流動配管１５が設けられている。混合流動配管１５には膜モジュール７から濃縮水を返送する返送管８と、排水処理用フィルタ設備１０から活性炭を返送する活性炭返送管１２が接続されている。
【００２７】
次に、本発明の膜濾過装置の他の実施形態について、図３の概略図を参照して説明する。図３に於いて、図１と同一部分には同一符号が付与されている。同一部分の説明は可能な限り省略する。同図に於いて、前処理フィルタ設備２、活性炭注入装置４、活性炭流動床１６を備える原水槽５、循環用ポンプ６、膜モジュール７、処理水槽１４、膜モジュール７と原水槽５との間に濃縮水を原水槽５に返送する返送管８と、膜モジュール７から排水用フィルタ設備１０に物理洗浄水を送水する送水管９と、排水用フィルタ設備１０から活性炭を原水槽５に返送する活性炭返送管１２と、排水管１１とが設けられている。この膜濾過装置には、処理水槽１４の濾過水が洗浄用ポンプ１３によって膜モジュール７に送り込まれ、膜モジュール７の膜裏面から濾過水による物理洗浄水が送り込まれる。膜モジュール７の膜面に付着する活性炭と懸濁物質が除去される。物理洗浄用設備は、図１の実施形態と同一である。
【００２８】
この実施形態では、活性炭流動床１６が原水槽５内に設けられ、原水１の流入に応じて、活性炭流動床１６から粉末活性炭及び粒状活性炭が流出して膜濾過装置の配管経路を循環している。原水中の溶解物質は、活性炭流動床１６を循環する活性炭によって吸着される。活性炭流動床１６から流出する活性炭は、活性炭注入設備４から活性炭流動床１６に補充される。又、活性炭は配管内を流動して循環することにより磨耗して粒径が小さくなり、排水用フィルタ設備１０のフィルタから排出される。排出された活性炭に相当する活性炭が活性炭注入装置４から活性炭流動床１６に補充される。無論、困難性を有するものの活性炭流動床１６から流出する活性炭量を制御するようにしてもよい。
【００２９】
次に、本発明の実施形態と従来の膜濾過装置とを比較して、その洗浄能力について説明する。図４は、原水中に含まれるアンモニア性窒素の除去について説明する。なお、図４に於いて、横軸は原水の膜濾過装置に通水日数を示し、縦軸は原水中のアンモニア性窒素除去率を示している。この比較検討に使用した原水の水質は、濁度が平均１１度であり、原水中にアンモニア性窒素は平均０．５ｍｇ／Ｌを含有しているものが使用された。又、本発明による実施形態と従来例の膜濾過装置における原水の通水条件は、表１に示した通りである。
【００３０】
【表１】

【００３１】
この比較検討の結果、原水の濁度は、表１に示した通水条件で、本発明の実施形態及び従来例の何れの場合も水の濁りは完全に除去された。しかし、図４に示したように、原水中のアンモニア性窒素除去率は、本発明の膜濾過装置では、除去特性曲線（イ）から明らかなように、通水日数が経過するに連れて除去率が上昇する。除去率は概ね通水日数が１５日を経過した時点で略９５％に達する。その後の除去率の変化はみられない。一方、従来例の膜濾過装置では、除去特性曲線（ロ）に示したように、除去率は通水日数にかかわりなく約１０％で略一定であった。すなわち、従来例の膜濾過装置では、原水中のアンモニア性窒素は十分に除去できないことを示しているのに対し、本実施形態の膜濾過装置では、アンモニア性窒素の除去が極めて効率よくなし得る。
【００３２】
本実施形態の膜濾過装置では、アンモニア性窒素が効率良く除去できる理由としては、活性炭が長期間系内に循環保持されるため、活性炭の表面に細菌が寄生して生物活性炭になり、原水に混入するアンモニア性窒素等の溶解物質が生物処理機能によって分解される。このように本実施形態の膜濾過装置では、生物活性炭による生物処理機能が十分に発揮されので、アンモニア性窒素やトリハロメタン生成能等の溶解性有機物が除去できる。
【００３３】
又、本実施形態では、活性炭が系内に一度注入されると、活性炭の処理能力が劣化するまでは系内に循環して保持される。古い活性炭ほど磨耗が激しいので粒径が小さくなり、吸着能力が低下している。従って、活性炭の吸着能力の低下は、活性炭が摩擦して粒径が小さくなることで察知することができるので、活性炭とともに物理洗浄水が膜モジュール７を経て排水用フィルタ設備１０に送られるた活性炭は、排水用フィルタ設備１０の排水用フィルタを通過して排水管１１を介し装置外に排出される。又、排水用フィルタ設備のフィルタの孔径は、活性炭の磨耗時間を考慮して設定されている。
【００３４】
又、上記実施形態に於いて、前処理フィルタ設備と排水処理用フィルタ設備のフィルタの孔径は、活性炭の粒径以上の１０μｍ以上であることが望ましい。前処理フィルタ設備及び排水処理用フィルタ設備のフィルタは原水中のコロイド状の物質を除去できる性能を要求するものではなく、前処理フィルタ設備では原水中の固形物を除去するものである。前処理フィルタ設備のフィルタの孔径は、粉末及び粒状活性炭の粒径以下のサイズであり、排水処理用フィルタ設備のフィルタの孔径は、前処理フィルタの孔径と等しいか、それ以下の孔径であればよい。例えば、前処理フィルタ設備と排水処理用フィルタ設備のフィルタの孔径が、１０μｍ以上である場合は、粉末活性炭及び粒状活性炭の粒径は、それ以上の孔径のものが要求される。
【００３５】
【発明の効果】
上記説明したように、本発明は、原水中の溶解性物質及び懸濁物質の除去における活性炭の処理効率を向上させるためのものであり、以下に示すような効果を得ることができる。
【００３６】
▲１▼活性炭を一度系内に注入すると処理能力が劣化するまで系内に保持されるために、活性炭が有効に利用できる利点がある。
▲２▼活性炭は長期間系内に保持されるので、活性炭の表面に細菌が寄生して生物活性炭になるために、生物による溶解性物質の生物処理機能が働いて、トリハロメタン生成能等の溶解性有機物によるものが除去できる。更に、活性炭に付着する溶解性有機物が生物処理機能によって除去されるので、活性炭表面の吸着機能が再生され、長期間除去能力が発揮できる利点があり、無論、アンモニア性窒素等の生物処理ができる利点がある。
▲３▼活性炭は長期間系内で循環するので摩擦によって磨耗して粒径が小さくなり、この粒径が小さくなった活性炭は吸着能力が低下したものと判断して、排水用フィルタ設備のフィルタを擦り抜けて系外に排出されるので、排水用フィルタ設備が汚泥で閉塞されることがない利点がある。
【００３７】
○４（丸数字の４）活性炭は原水と混合して、配管流路、原水槽、膜モジュール及び排水用フィルタ設備内流路を流動するダイナミックな混合流動活性炭となっているために、活性炭と原水中の有機物質との接触効率が向上し、溶解性有機物の吸着除去性能が向上する利点がある。
○５（丸数字の５）通常の活性炭流動床では活性炭の運転制御が困難であるが、本発明では活性炭の滞留時間を維持することにより、活性炭の吸着性能を向上させることができるので、原水中の溶解性有機物は容易に除去できる利点があり、他の通水条件の厳密な制御を必要としない利点がある。
【図面の簡単な説明】
【図１】本発明に係る膜濾過装置の一実施形態を示した概略図である。
【図２】本発明に係る膜濾過装置の他の実施形態を示した概略図である。
【図３】本発明に係る膜濾過装置の他の実施形態を示した概略図である。
【図４】通水日に対するアンモニア性窒素除去率を示す図である。
【図５】従来の膜濾過装置を示した概略図である。
【図６】従来の膜濾過装置を示した概略図である。
【図７】従来の膜濾過装置を示した概略図である。
【符号の説明】
１原水
２前処理フィルタ設備
３ドレン
４活性炭注入装置
５原水槽
６循環用ポンプ
７膜モジュール（膜濾過設備）
８濃縮水の返送管
９洗浄水の排水管
１０排水処理用フィルタ設備
１１排水管
１２返送管
１３洗浄用ポンプ
１４処理水槽
１５混合流動配管
１６活性炭流動床 [0001]
BACKGROUND OF THE INVENTION
The present invention relates to a membrane filtration device used for removing soluble substances and insoluble suspended substances in water treatment fields such as surface water, underground water, groundwater, and other water treatment processes, industrial water treatment, and wastewater treatment. And a membrane filtration method thereof.
[0002]
[Prior art]
In general, in water treatment, soluble substances such as odor-causing substances, synthetic detergents, phenols, and agricultural chemicals, which are formed by agglomeration, precipitation, sand filtration, etc. and cannot be removed by ordinary water treatment, are powdered and granular activated carbon. Has been removed by.
[0003]
In recent years, membrane treatment is used for water treatment instead of flocculation, precipitation, and sand filtration. Membrane filtration is superior to water treatment by sand filtration because it can reliably remove suspensions of a certain particle size or more compared to sand filtration. The substance has the disadvantage that it cannot be removed.
[0004]
As a method for improving such a problem, in the water treatment, by combining the membrane filtration treatment and the activated carbon treatment, the suspended substances can be removed, and the soluble substances can be surely removed. From this point of view, in recent water treatment methods, powdered activated carbon is injected into the treated water before membrane filtration to adsorb soluble substances, then treated water containing powdered activated carbon is subjected to membrane filtration treatment, and suspended substances At the same time, there is a treatment method for removing powdered activated carbon adsorbed with soluble substances.
[0005]
Examples of water treatment devices that combine such membrane filtration treatment and activated carbon treatment are, for example, (1) JP-A-5-154470, (2) JP-A-6-55046, and (3) JP-A-6. -226294 and the like, and will be sequentially described below with reference to the drawings.
[0006]
FIG. 5 shows a membrane filtration device disclosed in (1) Japanese Patent Laid-Open No. 5-154470. In the figure, raw water 1 is supplied to the raw water tank 19, and powdered activated carbon is fed into the raw water tank 19 from the activated carbon injector 4. The powdered activated carbon charged into the raw water 1 in the raw water tank 19 is stirred and mixed by the stirring device 18, and the soluble substance is adsorbed by the powdered activated carbon. The raw water in the raw water tank 19 is sucked from the membrane module 7 by operating the pump 17. The activated carbon mixed with the raw water is blocked by the membrane module 7, and the filtered water flows out to the treated water tank 14. In order to block the membrane module 7 along with the filtration, air is sent to the diffuser 21 by a blower, and bubbles are blown onto the membrane surface of the membrane module 7 to perform physical cleaning. Saturated activated carbon and sludge are discharged out of the apparatus through the exhaust valve 20.
[0007]
Next, {circle around (2)} a membrane filtration device disclosed in JP-A-6-55046 will be described with reference to FIG. In the figure, raw water 1 is supplied to a raw water tank (circulating water tank) 5 by removing contaminants in the raw water 1 by a pretreatment filter facility (autostona) 2, and powdered activated carbon is supplied from an activated carbon injector 4. It is poured into the water tank 5. The circulation pump 6 is activated to remove activated carbon, a membrane separation substance and scale (scale) from the membrane surface of the membrane filtration device (membrane module) 7, and the filtrate is recovered in the treated water tank 14. Spent activated carbon (including available activated carbon) and scale are returned to the circulating water tank 5 through the pipe 8, and the spent activated carbon (including available activated carbon) and scale adhered to the membrane surface of the membrane module 7 are intermittent. It is intermittently discharged outside the apparatus through the pipe 11.
[0008]
Next, (3) an advanced water purification apparatus disclosed in JP-A-6-226294 will be described with reference to FIG. Solids such as dust in the raw water 1 are removed, and powdered activated carbon is injected from the powdered activated carbon injector 4 and supplied to the raw water tank (biological reaction tank) 5. Ozonized air is supplied into the biological reaction tank 5 from the diffuser tube 24 through the ozonized air introduction tube 21. Water treated in the biological reaction tank 5 is introduced into a membrane module (membrane separation apparatus) 7, and chlorine is injected into the filtered water filtered by the membrane separation apparatus 7 from a chlorine injection pipe 25 and recovered into the treatment water tank. Is done. The powdered activated carbon and the biological treatment sludge are extracted from the pipe 8 and introduced into the concentration tank 22, and the supernatant water is returned to the biological reaction tank 5 through the pipe 23.
[0009]
[Problems to be solved by the invention]
However, in the membrane filtration apparatus of FIG. 5, the raw water and the activated carbon are stirred and mixed until the activated carbon is poured into the raw water tank 19 and the adsorption capacity is lost, and then the soluble substances are mainly removed. However, insoluble substances in the raw water are precipitated in the raw water tank 19. When the concentration of the insoluble substance is low, there is no problem, but when the concentration is high, it is desirable to separate the powdered activated carbon and the sludge component (suspended material) and discharge only the sludge component. However, although it is disclosed in FIG. 5 that it discharges through the mud valve 20, its separation method is not clearly described. When the sludge component is discharged through the mud valve 20, the powdered activated carbon is also discharged at the same time, which may deteriorate the removal efficiency of the soluble substance mixed in the raw water.
[0010]
Further, the membrane filtration device of FIG. 6 has used carbon, membrane separation material, scale, and the like discharged outside the device via the pipe 11, but has a drawback that it cannot be distinguished whether it is used carbon. Therefore, there is a drawback that the activated carbon having the adsorption ability is actually discharged out of the apparatus without being reused.
[0011]
In the advanced water treatment apparatus of FIG. 7, activated carbon and suspended substances are precipitated in the concentration tank 22, and only the supernatant water is returned to the biological reaction tank 5. In the concentration tank 22, the sludge concentration is increased and discharged outside the apparatus. However, it is difficult to distinguish whether the activated carbon is used or not as in the membrane filtration device of FIG. 6, and there is a disadvantage that the available activated carbon is discharged without being reused.
[0012]
The present invention has been made in view of the above problems, and removes soluble substances and insoluble suspended substances in raw water by combining activated carbon treatment with granular activated carbon or powdered activated carbon and membrane filtration treatment. In doing so, an object of the present invention is to provide a membrane filtration apparatus and a membrane filtration method in which the activated carbon used for the activated carbon treatment is effectively used to improve the water treatment efficiency by the activated carbon.
Another object of the present invention is to provide a membrane filtration device and a membrane filtration method that reduce the consumption of activated carbon when water treatment is performed by combining activated carbon treatment and membrane filtration treatment, thereby reducing water treatment costs. It is what.
[0013]
[Means for Solving the Problems]
The present invention has been made in order to achieve the above object, and the invention according to claim 1 is a membrane filtration method for filtering raw water, wherein a solid material having a predetermined size or more contained in the raw water is pretreated. In the process water, granular activated carbon or powdered activated carbon having a particle size equal to or larger than the above size is injected, and the activated carbon and suspended substances are filtered through a membrane filtration equipment to obtain filtered water, and the membrane surface of the membrane filtration equipment Suspended substances and activated carbon adhering to the surface are removed by physical washing water, and the physical washing water is filtered and discharged with a wastewater treatment filter having a pore diameter substantially equal to or larger than the pore diameter of the pretreatment filter, and the wastewater treatment The membrane filtration method is characterized in that the activated carbon blocked by the filter is returned before the membrane filtration equipment.
[0014]
The invention according to claim 2 is the membrane filtration method according to claim 1, wherein the treated water after the activated carbon is injected is retained in the raw water tank.
The invention according to claim 3 is the membrane filtration method according to claim 2, wherein the raw water tank is provided with an activated carbon fluidized bed to retain the treated water.
The invention according to claim 4 is the membrane filtration method according to any one of claims 1 to 3, wherein the activated carbon to be injected or the activated carbon used in the activated carbon fluidized bed has a particle size of 10 μm or more. It is a membrane filtration method.
[0015]
The invention of claim 5 is a membrane filtration device for filtering raw water,
Pretreatment filter equipment for removing solids of a predetermined size or more contained in the raw water, activated carbon injection equipment for injecting granular activated carbon or powdered activated carbon having a particle size equal to or larger than the solids removed by the pretreatment filter equipment,
A membrane filtration facility capable of removing suspended substances together with the activated carbon;
Physical washing means for removing suspended substances and activated carbon adhering to the membrane surface of the membrane filtration equipment from the membrane surface with physical washing water;
Among the suspended solids and activated carbon removed by the physical cleaning means, the wastewater treatment filter equipment that blocks activated carbon of a predetermined size or more and returns it before the membrane filtration equipment,
Is a membrane filtration device.
[0016]
The invention of claim 6 is a membrane filtration apparatus for filtering raw water,
Pretreatment filter equipment for removing solids of a predetermined size or more contained in raw water;
A raw water tank for retaining treated water treated by the pretreatment filter facility;
Activated carbon fluidized bed provided in the raw water tank;
Activated carbon injection equipment for supplying granular activated carbon or powdered activated carbon having a particle size equal to or larger than the solid matter removed by the pretreatment filter equipment to the activated carbon fluidized bed ,
A membrane filtration facility for removing suspended substances together with the activated carbon;
Physical washing means for physically washing suspended matter and activated carbon adhering to the membrane surface of the membrane filtration equipment with physical washing water;
Among the suspended solids and activated carbon removed by the physical washing means, wastewater treatment filter equipment for blocking activated carbon of a predetermined size or more and returning it to the raw water tank,
It is a membrane filtration apparatus characterized by comprising.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing an embodiment of a membrane filtration device according to the present invention. In the figure, the membrane filtration device includes a pretreatment filter facility 2, an activated carbon injection device 4, a raw water tank 5, a circulation pump 6, a membrane filtration facility (hereinafter referred to as a membrane module) 7, a drainage filter facility 10, and a treatment water tank. 14 and a cleaning pump 13, a return pipe 8 for returning the concentrated water to the raw water tank 5 between the membrane module 7 and the raw water tank 5, and a physical cleaning water for the activated carbon adhering to the membrane surface of the membrane module 7. In addition, a water supply pipe 9 for supplying water to the drainage filter equipment 10, an activated carbon return pipe 12 for returning the activated carbon adhering to the membrane surface of the drainage filter equipment 10 to the raw water tank 5, unnecessary activated carbon with particles worn out, soluble substances And a drain pipe 11 for discharging an insoluble suspended substance to the outside of the apparatus. These pipes are provided with valves as necessary. In this membrane filtration device, the filtered water in the treatment water tank 14 is sent to the membrane module 7 by the washing pump 13 to remove the activated carbon, soluble substances and insoluble suspended substances adhering to the membrane surface of the membrane module 7. Cleaning facilities are provided.
[0018]
Next, each said equipment etc. are demonstrated in detail.
The pre-processing filter equipment 2 uses a mesh screen, an artificially provided opening, or a filter in which plates are laminated at a predetermined interval and the interval is maintained at a predetermined interval. This is equipment that can remove solids of several tens μm or more. Further, the solid matter that gravity settles in the raw water is discharged through a drain 3 provided at the bottom of the pretreatment filter facility 2. Usually, a filter having a pore diameter of several hundreds of μm is used, as long as it can remove solids larger than the particle diameter of activated carbon injected into the treated water that has passed through the pretreatment filter equipment 2, The filter pore size must be smaller than the activated carbon particle size.
[0019]
The activated carbon injection device 4 is a facility for injecting activated carbon into the raw water that has passed through the filtration membrane of the pretreatment filter facility 2. Once a certain amount of activated carbon has been injected, the treatment capacity of the activated carbon is reduced and discharged outside the apparatus. There is no need to replenish the amount and constantly inject activated charcoal. In this embodiment, activated carbon is injected after the treatment by the pretreatment filter equipment 2, but the activated carbon may be injected in any place without being limited to the embodiment. For example, activated carbon may be directly supplied to the raw water tank 5 to which raw water is supplied. Further, when an activated carbon fluidized bed is provided in the raw water tank 5, as will be described in detail with reference to FIG. Further, the outflow activated carbon is actively used to adsorb dissolved substances by the mixed fluidized activated carbon that has flowed in the piping, and when the activated carbon is worn down to a predetermined size or less, the exhaust filter device 10 is rubbed through the membrane. It is discharged out of the device.
[0020]
The raw water tank 5 has a function of sufficiently mixing the activated carbon and the raw water by temporarily storing the raw water, sufficiently mixing the activated carbon and the raw water, and retaining the raw water for a certain period of time. Although not shown, a stirring device may be provided in the raw water tank 5 to sufficiently mix the treated water and activated carbon. In addition, when the raw water is treated with activated carbon, a certain residence time is required for the raw water to be sufficiently mixed with the activated carbon. If the length of the pipe into which the activated carbon is injected is long enough to maintain the residence time, the raw water is not necessarily used. It is not necessary to use the water tank 5. Of course, the residence time varies depending on the quality of the raw water, but it needs to be maintained for about 5 to 30 minutes. Embodiment which does not use a raw | natural water tank is described with reference to FIG.
[0021]
The membrane module 7 is provided with a filtration membrane (filter), the raw water in the raw water tank 5 is fed through the circulation pump 6, activated carbon and suspended substances in the raw water are filtered by the filtration membrane, and the filtered water is treated water tank 14. On the other hand, the filtered water in the treated water tank 14 is used for various purposes. Further, the filtered water is supplied to the membrane module 7 and used as washing water for removing activated carbon and suspended substances adhering to the surface of the membrane of the membrane module 7. The membrane of the membrane module 7 is a membrane made of a material such as synthetic fiber, glass, resin, or ceramic, and the membrane can be any of a tubular membrane, a multi-lumen membrane, and a flat membrane. The type of membrane may be any of a microfiltration membrane, an ultrafiltration membrane, a reverse osmosis membrane, and the like. The pore size of the filtration membrane is a pore size capable of blocking activated carbon and suspended substances, and is generally 0.4 μm or less.
[0022]
The cleaning pump 13 supplies the filtered water from the treated water tank 14 to the membrane module 7 as physical cleaning water, and applies water pressure to the rear surface of the membrane of the membrane module 7 to remove suspended substances and activated carbon adhering to the membrane. It peels off with physical washing water and is sent to the waste water treatment filter device 10 through the water pipe 9. The filtration membrane of the membrane module 7 is subjected to a pressure opposite to that at the time of physical cleaning and filtration, and a predetermined water pressure is also applied to the filter of the filter device 10 for wastewater treatment. In addition, the suspended matter and activated carbon adhering to the filtration membrane of the membrane module 7 are removed as described above by the reverse pressure washing means (1) for adding physical washing water to the back surface of the filtration membrane and the filtration membrane surface. There are air peeling means (air scrubbing) (2) for blowing bubbles to the surface, back pressure washing with high pressure air (3), and the like. Any cleaning method may be used, but it is necessary to send the suspended solids and activated carbon separated from the filtration membrane to the wastewater treatment filter 10, and at the same time wash the filtered water even in the case of reverse pressure washing with air separation means or high-pressure air. In the case of the air pump 13 or the air peeling means (2) or the counter pressure washing (3), the pump 6 sends the air to the filter 10.
[0023]
The wastewater treatment filter facility 10 prevents activated carbon and the like mixed in the physical washing water sent through the water pipe 9 with a filter, and returns the blocked activated carbon and the like to the raw water tank 5 through the activated carbon return pipe 12 and restarts. It is equipment for use. The pore size of the wastewater treatment filter of the wastewater treatment filter facility 10 needs to be approximately equal to or smaller than the pore size of the filter of the pretreatment filter facility 2 provided in the previous stage of the raw water tank 5. The filtered water from the treatment water tank 14 is sent to the membrane module 7 by the washing pump 13, and this physical washing water is passed through the filtration membrane of the membrane module 7 and sent to the wastewater treatment filter equipment 10 through the water supply pipe 9. . The washing water from which the activated carbon has been removed is discharged through the drain pipe 11.
[0024]
Next, the membrane filtration process and the membrane filtration back washing process according to the embodiment of FIG. 1 will be described according to the process steps. First, the membrane filtration process will be described. The raw water 1 is supplied to the pretreatment filter equipment 2, and after removing solids of a certain size or larger by the pretreatment filter equipment 2, the size of the pretreatment filter equipment 2 from the activated carbon injection device 4. Granular activated carbon or powdered activated carbon having the above particle diameter is injected. Dissolved substances such as ammonia, trihalomethane, and agricultural chemicals in raw water are adsorbed by these activated carbons. The activated carbon and suspended substances in the raw water are sent to the membrane module 7 by the circulation pump 6, filtered by membrane filtration of the membrane module 7, and the filtered water is sent to the treated water tank 14.
[0025]
Next, the membrane filtration backwashing process will be described. The filtered water in the treated water tank 14 is sent as physical washing water to the back side of the membrane of the membrane module 7 by the washing pump 13, and the water pressure by this physical washing water Suspended substances and activated carbon adhering to the surface side of the filtration membrane are peeled off. A water pressure is applied to the filtration membrane, contrary to the filtration treatment, and so-called back pressure cleaning is performed. The suspended suspended matter and activated carbon are fed into the wastewater treatment filter facility 10 through the water pipe 9 together with the physical cleaning wastewater. In the wastewater treatment filter facility 10, the suspended matter that has been filtered through a filtration membrane (drainage treatment filter) having a pore size of a certain size and passed through the filtration membrane is removed outside the device through the drainage pipe 11, and the filter The granular activated carbon or the powdered activated carbon having a certain size or larger, which is blocked by the above, is fed into the raw water tank 5 through the return pipe 12. The activated carbon circulates through the paths of the raw water tank 5, the membrane module 7, and the wastewater treatment filter facility 10 and is held in the filtration cleaning system. Activated carbon is circulated and used until the adsorption capacity is lost, and when the activated carbon is worn out and the adsorption capacity is lost, the activated carbon and suspended substances are discharged out of the apparatus through the drainage pipe 11 through the wastewater treatment filter facility 10. Thus, it is possible to prevent sludge from accumulating in the membrane filtration device system, particularly in the raw water tank 5. Of course, although not shown, the sediment is discharged from the drain of the raw water tank 5.
[0026]
Next, another embodiment of the membrane filtration device of the present invention will be described with reference to the schematic diagram of FIG. In FIG. 2, the same parts as those in FIG. 1 are denoted by the same reference numerals, and the description of the same parts is omitted.
In the figure, instead of the raw water tank 5 in FIG. 1, a mixed flow pipe 15 through which activated carbon flows is provided between the pretreatment filter equipment 2 and the circulation pump 6. The activated carbon injection equipment 4 is connected to the raw water inflow side of the mixed flow pipe 15, and granular activated carbon and powdered activated carbon are injected from the activated carbon injection equipment 4 into the mixed flow pipe 15 to sufficiently adsorb dissolved substances in the raw water. A mixed flow pipe 15 having a sufficient pipe length is provided. A return pipe 8 that returns concentrated water from the membrane module 7 and an activated carbon return pipe 12 that returns activated carbon from the wastewater treatment filter facility 10 are connected to the mixed flow pipe 15.
[0027]
Next, another embodiment of the membrane filtration device of the present invention will be described with reference to the schematic view of FIG. In FIG. 3, the same parts as those in FIG. The description of the same part is omitted as much as possible. In the figure, a pretreatment filter facility 2, an activated carbon injection device 4, a raw water tank 5 having an activated carbon fluidized bed 16, a circulation pump 6, a membrane module 7, a treated water tank 14, and between the membrane module 7 and the raw water tank 5. Returning the concentrated water to the raw water tank 5, returning the activated water from the membrane module 7 to the drainage filter equipment 10, and returning the activated carbon from the drainage filter equipment 10 to the raw water tank 5. An activated carbon return pipe 12 and a drain pipe 11 are provided. In this membrane filtration device, the filtered water in the treated water tank 14 is sent to the membrane module 7 by the cleaning pump 13, and the physical cleaning water by filtered water is sent from the membrane back surface of the membrane module 7. Activated carbon and suspended substances adhering to the membrane surface of the membrane module 7 are removed. The physical cleaning equipment is the same as in the embodiment of FIG.
[0028]
In this embodiment, the activated carbon fluidized bed 16 is provided in the raw water tank 5, and in response to the inflow of the raw water 1, the powdered activated carbon and the granular activated carbon flow out from the activated carbon fluidized bed 16 and circulate through the piping path of the membrane filtration device. Yes. The dissolved substance in the raw water is adsorbed by the activated carbon circulating in the activated carbon fluidized bed 16 . The activated carbon flowing out from the activated carbon fluidized bed 16 is replenished to the activated carbon fluidized bed 16 from the activated carbon injection facility 4. Further, the activated carbon is worn by flowing and circulating in the piping, the particle size becomes small, and is discharged from the filter of the drainage filter facility 10. Activated carbon corresponding to the discharged activated carbon is replenished to the activated carbon fluidized bed 16 from the activated carbon injector 4. Of course, although it has difficulty, you may make it control the amount of activated carbon which flows out from the activated carbon fluidized bed 16.
[0029]
Next, the cleaning ability will be described by comparing the embodiment of the present invention with a conventional membrane filtration device. FIG. 4 explains the removal of ammonia nitrogen contained in the raw water. In FIG. 4, the horizontal axis indicates the number of days of water passing through the raw water membrane filtration apparatus, and the vertical axis indicates the ammonia nitrogen removal rate in the raw water. The quality of the raw water used in this comparative study has an average turbidity of 11 degrees, and the raw water contains an average of 0.5 mg / L of ammoniacal nitrogen. In addition, the flow conditions of the raw water in the embodiment of the present invention and the conventional membrane filtration apparatus are as shown in Table 1.
[0030]
[Table 1]

[0031]
As a result of this comparative study, the turbidity of the raw water was completely removed under the water flow conditions shown in Table 1 in both the embodiment of the present invention and the conventional example. However, as shown in FIG. 4, in the membrane filtration device of the present invention, the ammonia nitrogen removal rate in the raw water is removed as the passage time elapses, as is apparent from the removal characteristic curve (a). The rate goes up. The removal rate reaches approximately 95% when the number of water passage days has passed 15 days. There is no change in the removal rate thereafter. On the other hand, in the conventional membrane filtration apparatus, as shown in the removal characteristic curve (b), the removal rate was approximately constant at about 10% regardless of the number of days of water passage. That is, the membrane filter of the conventional example shows that ammonia nitrogen in the raw water cannot be removed sufficiently, whereas the membrane nitrogen filter of this embodiment can remove ammonia nitrogen very efficiently. .
[0032]
In the membrane filtration apparatus of this embodiment, the reason why ammonia nitrogen can be efficiently removed is that activated carbon is circulated and held in the system for a long period of time. The dissolved substance such as ammonia nitrogen mixed in is decomposed by the biological treatment function. Thus, in the membrane filtration apparatus of this embodiment, the biological treatment function by the biological activated carbon is sufficiently exhibited, so that soluble organic substances such as ammonia nitrogen and trihalomethane generating ability can be removed.
[0033]
Moreover, in this embodiment, once activated carbon is injected into the system, it is circulated and held in the system until the treatment capacity of the activated carbon deteriorates. Older activated carbon is more worn out, so the particle size is smaller and the adsorption capacity is reduced. Therefore, the decrease in the adsorption capacity of the activated carbon can be detected by the friction of the activated carbon and the particle size becomes smaller. Therefore, the activated carbon in which the physical cleaning water is sent to the drainage filter facility 10 through the membrane module 7 together with the activated carbon. Passes through the drainage filter of the drainage filter facility 10 and is discharged out of the apparatus via the drainage pipe 11. Further, the pore diameter of the filter of the drainage filter equipment is set in consideration of the wear time of the activated carbon.
[0034]
Moreover, in the said embodiment, it is desirable for the hole diameter of the filter of a pre-processing filter installation and the waste water treatment filter installation to be 10 micrometers or more larger than the particle diameter of activated carbon. The filters of the pretreatment filter equipment and the wastewater treatment filter equipment do not require the ability to remove colloidal substances in the raw water, and the pretreatment filter equipment removes solids in the raw water. The pore diameter of the filter of the pretreatment filter equipment is the size of the powder and granular activated carbon or less, and the pore diameter of the filter of the wastewater treatment filter equipment is equal to or smaller than the pore diameter of the pretreatment filter. Good. For example, when the pore diameters of the filters of the pretreatment filter facility and the wastewater treatment filter facility are 10 μm or more, the powdered activated carbon and the granular activated carbon are required to have a larger particle diameter.
[0035]
【The invention's effect】
As described above, the present invention is for improving the treatment efficiency of activated carbon in the removal of soluble substances and suspended substances in raw water, and the following effects can be obtained.
[0036]
(1) Once activated carbon is injected into the system, it is held in the system until the treatment capacity deteriorates, and therefore there is an advantage that activated carbon can be used effectively.
(2) Since the activated carbon is retained in the system for a long time, since the bacteria are parasitic on the surface of the activated carbon to become biological activated carbon, the biological treatment function of soluble substances by living organisms works, so that trihalomethane generating ability etc. dissolves It can be removed by organic substances. Furthermore, since the soluble organic substances adhering to the activated carbon are removed by the biological treatment function, there is an advantage that the adsorption function of the activated carbon surface is regenerated and the removal ability can be exhibited for a long time. Of course, biological treatment such as ammonia nitrogen can be performed. There are advantages.
(3) Since the activated carbon circulates in the system for a long period of time, it wears due to friction and the particle size becomes small, and it is judged that the activated carbon having this small particle size has deteriorated the adsorption capacity. Is drained out of the system, and there is an advantage that the filter equipment for drainage is not blocked by sludge.
[0037]
○ 4 (circled number 4) Activated carbon is mixed with raw water and becomes a dynamic mixed flow activated carbon that flows through the flow path in the piping flow path, raw water tank, membrane module and drainage filter equipment. There is an advantage that the contact efficiency with the organic substance in the raw water is improved, and the adsorption removal performance of the soluble organic matter is improved.
○ 5 (circle number 5) Although it is difficult to control the operation of the activated carbon in the normal activated carbon fluidized bed , the adsorption performance of the activated carbon can be improved by maintaining the residence time of the activated carbon in the present invention. Dissolved organics in water have the advantage that they can be easily removed and do not require strict control of other water flow conditions.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an embodiment of a membrane filtration device according to the present invention.
FIG. 2 is a schematic view showing another embodiment of the membrane filtration device according to the present invention.
FIG. 3 is a schematic view showing another embodiment of the membrane filtration device according to the present invention.
FIG. 4 is a graph showing an ammonia nitrogen removal rate with respect to a water passage day.
FIG. 5 is a schematic view showing a conventional membrane filtration apparatus.
FIG. 6 is a schematic view showing a conventional membrane filtration apparatus.
FIG. 7 is a schematic view showing a conventional membrane filtration apparatus.
[Explanation of symbols]
1 Raw Water 2 Pretreatment Filter Equipment 3 Drain 4 Activated Carbon Injection Device 5 Raw Water Tank 6 Circulation Pump 7 Membrane Module (Membrane Filtration Equipment)
8 Condensed water return pipe 9 Wash water drain pipe 10 Wastewater treatment filter equipment 11 Drainage pipe 12 Return pipe 13 Washing pump 14 Treatment water tank 15 Mixing flow piping 16 Activated carbon fluidized bed

Claims

In a membrane filtration method for filtering raw water,
Solids larger than a predetermined size contained in the raw water are removed with a pretreatment filter, granular activated carbon or powdered activated carbon with a particle size larger than the above size is injected into the treated water, and the activated carbon and suspended substances are filtered through a membrane filtration facility. To obtain filtered water, and to remove suspended substances and activated carbon adhering to the membrane surface of the membrane filtration equipment with physical washing water, for wastewater treatment with a pore size substantially equal to or smaller than the pore size of the pretreatment filter A membrane filtration method, wherein the physical washing water is filtered and discharged by a filter, and the activated carbon blocked by the wastewater treatment filter is returned before the membrane filtration equipment.

In the membrane filtration method according to claim 1,
A membrane filtration method characterized by retaining treated water after injecting the activated carbon in a raw water tank.

In the membrane filtration method according to claim 2,
A membrane filtration method comprising providing an activated carbon fluidized bed in the raw water tank to retain the treated water.

In the membrane filtration method according to any one of claims 1 to 3,
A membrane filtration method, wherein the activated carbon used for injection or the activated carbon fluidized bed has a particle size of 10 μm or more.

In a membrane filtration device that filters raw water,
Pretreatment filter equipment for removing solids of a predetermined size or more contained in the raw water, activated carbon injection equipment for injecting granular activated carbon or powdered activated carbon having a particle size equal to or larger than the solids removed by the pretreatment filter equipment,
A membrane filtration facility for removing suspended substances together with the activated carbon;
Physical washing means for removing suspended substances and activated carbon adhering to the membrane surface of the membrane filtration equipment from the membrane surface with physical washing water;
Among the suspended solids and activated carbon removed by the physical cleaning means, waste water treatment filter equipment for blocking activated carbon of a predetermined size or more and returning it before the membrane filtration equipment,
A membrane filtration apparatus comprising:

In a membrane filtration device that filters raw water,
Pretreatment filter equipment for removing solids of a predetermined size or more contained in raw water;
A raw water tank for retaining treated water treated by the pretreatment filter facility;
Activated carbon fluidized bed provided in the raw water tank;
Activated carbon injection equipment for supplying granular activated carbon or powdered activated carbon having a particle size equal to or larger than the solid matter removed by the pretreatment filter equipment to the activated carbon fluidized bed ,
A membrane filtration facility for removing suspended substances together with the activated carbon;
Physical washing means for removing suspended substances and activated carbon adhering to the membrane surface of the membrane filtration equipment from the membrane surface with physical washing water;
Among the suspended solids and activated carbon removed by the physical washing means, wastewater treatment filter equipment for blocking activated carbon of a predetermined size or more and returning it to the raw water tank,
A membrane filtration apparatus comprising: