JP4102681B2

JP4102681B2 - Water treatment system

Info

Publication number: JP4102681B2
Application number: JP2003055512A
Authority: JP
Inventors: 規孝柴田; 和史近藤; 振家張
Original assignee: Mitsubishi Chemical Corp; Mitsubishi Rayon Co Ltd
Current assignee: Mitsubishi Chemical Corp; Mitsubishi Rayon Co Ltd
Priority date: 2003-03-03
Filing date: 2003-03-03
Publication date: 2008-06-18
Anticipated expiration: 2023-03-03
Also published as: JP2004261730A

Description

【０００１】
【発明の属する技術分野】
本発明は、水処理システムおよび水処理方法に関し、特に、食品工場、アルコール工場、畜産施設等からの排出される、窒素、リンを高濃度に含む排液を処理するための水処理システムおよび水処理方法に関する。
【０００２】
【従来の技術】
酢酸発酵工程やアルコール発酵工程から発生する排液は、通常、ＵＡＳＢ法（上向流嫌気性スラッジベッド法）等による嫌気処理装置により処理され、嫌気処理装置にて排液中のＣＯＤ（化学的酸素要求量）の低減、および有用メタンガスの回収が行われている。嫌気処理された排液は、十分にＣＯＤが低減されているものの、依然、アンモニウムイオン濃度で１０００ｍｇ／Ｌ以上の窒素成分、および高濃度のリン成分を含んでいる。近年、環境問題への関心の高まり、排液への規制強化などに伴い、アルコール発酵排液に高濃度に含まれる窒素成分の除去が必要となってきている。
【０００３】
排液中に含まれるアンモニア性窒素（ＮＨ₄ −Ｎ）を除去する方法としては、亜硝化菌、硝化菌によりＮＨ₄ ⁺をＮＯ₂ ^-、ＮＯ₃ ^-に酸化（硝化）し、さらに脱窒菌により窒素ガスとする、標準活性汚泥法などの生物学的硝化脱窒法が知られている。
しかしながら、ＵＡＳＢ法等によって嫌気処理された排液は、水素供与体成分（ＢＯＤ成分）に対する窒素成分の濃度が高すぎるため、このままでは標準活性汚泥法による生物処理ができない。生物処理を行うためには、ｐＨ調整、メタノールの投入などの必要があり、処理コストが高くなると言う問題があった。
【０００４】
排液中に含まれるアンモニア性窒素を除去する方法としては、ゼオライトによるアンモニア性窒素の選択的吸着性に着目した方法が開示されている。
特開平１１−２３９７８５号公報には、ゼオライトのナトリウムイオン、カリウムイオンの一部をマグネシウムイオンで置換した置換ゼオライトを用いる方法が開示されている。この方法によれば、排液中のアンモニウムイオン濃度が３０ｍｇ／Ｌ以下の濃度であれば、安定した処理が可能である。しかしながら、アンモニウムイオン濃度が３０ｍｇ／Ｌを超える、特に１０００ｍｇ／Ｌ以上となると、置換ゼオライト単位質量あたりに吸着されたアンモニウムイオンが少ない状態で吸着平衡に達してしまうため、置換ゼオライトが本来有する吸着容量を効率よく使うことができず、置換ゼオライトの投入量が増え、処理コストが高くなるという問題があった。
【０００５】
【特許文献１】
特開平１１−２３９７８５号公報（第２−６頁）
【０００６】
【発明が解決しようとする課題】
よって、本発明の目的は、対象物質を高濃度に含む被処理水中の対象物質を低コストで除去できる水処理システムおよび水処理方法を提供することにある。
【０００７】
【課題を解決するための手段】
すなわち、本発明の水処理システムは、被処理水中のアンモニウムイオンを吸着剤に吸着させる吸着処理手段を２段で１組とした多段吸着処理手段を２組以上具備し、各多段吸着処理手段ごとに、後段側の吸着処理手段の被処理水に吸着剤を投入する吸着剤投入手段と、後段側の吸着処理手段で使用した吸着剤を前段側の吸着処理手段に移送する吸着剤移送手段とが設けられていることを特徴とするものである。
【０００８】
また、本発明の水処理システムは、吸着処理手段で処理された被処理水を生物学的に処理する生物処理手段を具備することが望ましい。
また、本発明の水処理システムは、多段吸着処理手段よりも前段側に、被処理水を嫌気菌によって処理する嫌気処理手段を具備することが望ましい。
前記吸着剤は、ゼオライトであることが望ましい。
【００１１】
【発明の実施の形態】
以下、本発明を詳しく説明する。
（形態例１）
図１は、本発明の水処理システムの一形態例を示す概略構成図である。この水処理システムは、被処理水中の固形分を沈澱させる第１の沈殿槽１１および第２の沈殿槽１２と、被処理水の水温、ｐＨ等を調整する第１の調整槽１３および第２の調整槽１４と、被処理水を嫌気菌によって処理する第１の嫌気処理装置１５および第２の嫌気処理装置１６（嫌気処理手段）と、被処理水の水温、ｐＨ、水量等を調整する二次調整槽１７と、被処理水中の対象物質を吸着剤に吸着させる第１の吸着処理装置１８および第２の吸着処理装置１９（吸着処理手段）からなる第１の多段吸着処理装置２０（多段吸着処理手段）と、第３の吸着処理装置２１および第４の吸着処理装置２２（吸着処理手段）からなる第２の多段吸着処理装置２３（多段吸着処理手段）と、吸着処理装置で処理された被処理水を生物学的に処理する接触酸化装置２４（生物処理手段）と、接触酸化装置１３で処理された被処理水の固液分離を行う加圧浮上分離装置２５と、第２の吸着処理装置１９の被処理水に吸着剤を投入する第１の吸着剤投入装置２６（吸着剤投入手段）と、第４の吸着処理装置２２の被処理水に吸着剤を投入する第２の吸着剤投入装置２７（吸着剤投入手段）と、第２の吸着処理装置１９で使用した吸着剤を第１の吸着処理装置１８に移送する第１の吸着剤移送装置２８（吸着剤移送手段）と、第４の吸着処理装置２２で使用した吸着剤を第３の吸着処理装置２１に移送する第２の吸着剤移送装置２９（吸着剤移送手段）と、第１の吸着処理装置１８で使用した吸着剤を回収する第１の吸着剤回収装置３０と、第３の吸着処理装置２１で使用した吸着剤を回収する第２の吸着剤回収装置３１と、第２の調整槽１４から第１の嫌気処理装置１５へ被処理水を送液する第１の被処理水供給装置３２と、二次調整槽１７から第１の吸着処理装置１８へ被処理水を送液する第２の被処理水供給装置３３とを具備して概略構成されるものである。
【００１２】
第１の沈殿槽１１は、主に粒径１ｍｍ以上の比較的大きい固形物を沈殿させるための槽であり、第２の沈殿槽１２は、主に粒径１ｍｍ以下の比較的小さい固形物を沈殿させるための槽である。
第１の調整槽１３および第２の調整槽１４は、被処理水の水温、ｐＨ、水量等の調整を行うものである。また、後段の嫌気処理装置における嫌気菌の栄養源である微量の金属を添加するための槽である。
【００１３】
嫌気処理手段は、エネルギー（メタンガス）回収およびＣＯＤ低減を行うものである。具体的には、第１の嫌気処理装置１５は、被処理水を嫌気菌で処理して主に酸を生成させるものであり、第２の嫌気処理装置１６は、被処理水を嫌気菌でさらに処理して主にメタンを生成させるものである。
嫌気処理装置としては、ＵＡＳＢ法（上向流嫌気性スラッジベッド法）による装置、ＥＧＳＢ法（膨張顆粒スラッジベッド法）による装置など、上向流嫌気性処理装置を用いることができる。
【００１４】
第１の吸着処理装置１８は、被処理水と吸着剤とを接触させる部分と吸着剤を沈降分離させる部分とを有する吸着処理槽３４と、吸着処理槽３４内の被処理水を攪拌する攪拌装置３５とを備えたものである。
同様に、第２の吸着処理装置１９は、吸着処理槽３６と、攪拌装置３７とを備えたものであり、第１の吸着処理装置１８で処理された被処理水が重力によって第２の吸着処理装置１９へと流れるように、第１の吸着処理装置１８よりも低い位置に設置されているものである。
【００１５】
同様に、第３の吸着処理装置２１は、吸着処理槽３８と、攪拌装置３９とを備えたものであり、第２の吸着処理装置１９で処理された被処理水が重力によって第３の吸着処理装置２１へと流れるように、第２の吸着処理装置１９よりも低い位置に設置されているものである。
同様に、第４の吸着処理装置２２は、吸着処理槽４０と、攪拌装置４１とを備えたものであり、第３の吸着処理装置２１で処理された被処理水が重力によって第４の吸着処理装置２２へと流れるように、第３の吸着処理装置２１よりも低い位置に設置されているものである。
【００１６】
接触酸化装置２４は、接触酸化槽４２と、この中に配置された、好気性微生物（汚泥）を付着させる接触材４３と、接触酸化槽４２に空気を供給するブロアポンプ４４と、接触材４３の下方に配置され、ブロアポンプ４４からの空気を接触酸化槽４２内に散気する散気管４５とを備えたものである。
加圧浮上分離装置２５は、加圧によって被処理水内に発生した微細な気泡により被処理水内の汚泥を浮上させ、被処理水を汚泥および処理水に分離するものであり、固液分離槽４６と、固液分離槽４６内の被処理水を加圧する、加圧ポンプ、加圧タンク等の加圧手段（図示略）と、浮上した汚泥を掻き取る、スクレーパー等の掻き取り手段４７とを備えたものである。
【００１７】
第１の吸着剤投入装置２６は、第１の多段吸着処理装置２０を構成する２つの吸着処理装置の内、後段側の第２の吸着処理装置１９へ吸着剤を投入するものであり、吸着剤を貯留する貯留容器（図示略）と、吸着剤を第２の吸着処理装置１９へ投入するための投入口（図示略）と、投入口に設けられた、吸着剤の投入速度（時間あたりの投入量）を調整する調整機構（図示略）とを備えたものである。
同様に、第２の吸着剤投入装置２７は、第２の多段吸着処理装置２３を構成する２つの吸着処理装置の内、後段側の第４の吸着処理装置２２へ吸着剤を投入するものであり、吸着剤を貯留する貯留容器（図示略）と、吸着剤を第４の吸着処理装置２２へ投入するための投入口（図示略）と、投入口に設けられた、吸着剤の投入速度（時間あたりの投入量）を調整する調整機構（図示略）とを備えたものである。
【００１８】
第１の吸着剤移送装置２８は、第２の吸着処理装置１９の吸着処理槽３６の底に、凝集剤によって凝集、沈降した吸着剤を若干の被処理水とともに回収し、第１の吸着処理装置１８に供給するものである。
第２の吸着剤移送装置２９は、第４の吸着処理装置２２の吸着処理槽４０の底に、凝集剤によって凝集、沈降した吸着剤を若干の被処理水とともに回収し、第３の吸着処理装置２１に供給するものである。
これら吸着剤移送装置としては、例えば、スクリューポンプ、スネークポンプ、ギアポンプ、カスケードポンプ、チューブポンプなどの中から、吸着剤の粘性、濃度、量などに応じて適宜選択して用いることができる。
【００１９】
第１の吸着剤回収装置３０は、第１の吸着処理装置１８の吸着処理槽３４の底に沈降した吸着剤を若干の被処理水とともに回収し、吸着剤脱水装置（図示略）に移送するものである。
第２の吸着剤回収装置３１は、第３の吸着処理装置２１の吸着処理槽３８の底に沈降した吸着剤を若干の被処理水とともに回収し、吸着剤脱水装置（図示略）に移送するものである。
これら吸着剤回収装置としては、例えば、スクリューポンプ、スネークポンプ、ギアポンプ、カスケードポンプ、チューブポンプなどの中から、吸着剤の粘性、濃度、量などに応じて適宜選択して用いることができる。
【００２０】
吸着剤脱水装置（図示略）は、吸着処理装置から回収された吸着剤から水を脱水し、脱水による排水を二次調整槽１７に戻し、脱水された吸着剤を得るものである。吸着剤脱水装置としては、ロール脱水方式の脱水機、加圧脱水方式の脱水機、真空脱水方式の脱水機などを用いることができる。
また、第１の多段吸着処理装置２０および第２の多段吸着処理装置２３には、それぞれを構成する２つの吸着処理装置の内、後段側の吸着処理装置へ凝集剤を投入する凝集剤投入装置（図示略）を付設するものとする。
【００２１】
次に、図示例の水処理システムを用いた水処理方法について説明する。
この水処理システムの運転開始前には、まず、第１の嫌気処理装置１５および第２の嫌気処理装置１６内に嫌気菌を植種し、培養する。また、接触酸化装置２４に種汚泥を植種し、担体である接触材４３に好気性微生物を付着させる。
さらに、第２の吸着処理装置１９に吸着剤投入装置２６から吸着剤を所定量投入し、第２の吸着処理装置１９において所定時間、吸着処理を行った後、第１の吸着剤移送装置２８を作動させ、第２の吸着処理装置１９の吸着処理槽３６の底に、凝集剤によって凝集、沈降した吸着剤を若干の被処理水とともに回収し、所定量の吸着剤を第１の吸着処理装置１８に供給する。同様に、第４の吸着処理装置２２に第２の吸着剤投入装置２７から吸着剤を所定量投入し、第４の吸着処理装置２２において所定時間、吸着処理を行った後、第２の吸着剤移送装置２９を作動させ、第４の吸着処理装置２２の吸着処理槽４０の底に、凝集剤によって凝集、沈降した吸着剤を若干の被処理水とともに回収し、所定量の吸着剤を第３の吸着処理装置２１に供給する。
【００２２】
このようにして各装置の条件を調整した後、連続運転を開始する。
まず、アルコール発酵などの排液（被処理水）は、第１の沈殿槽１１、続いて第２の沈殿槽１２に導入され、被処理水中の固形分が沈殿により除去される。
沈殿により固形物を除去された被処理水は、第１の調整槽１３、続いて第２の調整槽１４に供給され、その水温、ｐＨ等が調整される。また、第２の調整槽１４にて、嫌気菌の栄養源である微量の金属が被処理水に添加される。
被処理水に固形分が含まれていない場合は、第１の沈殿槽１１および第２の沈殿槽１２に通さずに、被処理水を直接第１の調整槽１３に供給してもよい。
【００２３】
水温、ｐＨ等が調整された被処理水は、第１の被処理水供給装置３２によって第１の嫌気処理装置１５に送られ、第１の嫌気処理装置１５にて嫌気菌で処理され、ここで主に酸が生成される。続いて、被処理水は、第２の嫌気処理装置１６にて嫌気菌でさらに処理され、ここで主にメタンが生成される。
嫌気処理された被処理水は、二次調整槽１７に送られ、その水温、ｐＨ、水量等が調整される。
【００２４】
第２の被処理水供給装置３３によって二次調整槽１７から第１の吸着処理装置１８に連続的に供給された被処理水は、まず、第１の吸着処理装置１８において吸着剤と接触し、被処理水中の対象物質が吸着剤に吸着される。第１の吸着処理装置１８において吸着処理された被処理水は、第１の吸着処理装置１８から溢れ、第１の吸着処理装置１８と第２の吸着処理装置１９との高低差によって第２の吸着処理装置１２に供給され、第２の吸着処理装置１９において吸着剤と接触し、被処理水中の対象物質が吸着剤に吸着される。
【００２５】
第２の吸着処理装置１９において吸着処理された被処理水は、第２の吸着処理装置１９から溢れ、第２の吸着処理装置１９と第３の吸着処理装置２１との高低差によって第３の吸着処理装置２１に供給され、第３の吸着処理装置２１において吸着剤と接触し、被処理水中の対象物質が吸着剤に吸着される。第３の吸着処理装置２１において吸着処理された被処理水は、第３の吸着処理装置２１から溢れ、第３の吸着処理装置２１と第４の吸着処理装置２２との高低差によって第４の吸着処理装置２２に供給され、第４の吸着処理装置２２において吸着剤と接触し、被処理水中の対象物質が吸着剤に吸着される。
【００２６】
第４の吸着処理装置２２において吸着処理された被処理水は、第４の吸着処理装置２２から溢れ、第４の吸着処理装置２２と接触酸化装置２４との高低差によって接触酸化装置２４に供給され、接触酸化装置２４において生物学的に処理される。具体的には、好気性微生物（汚泥）が付着した接触材４３にブロアポンプ４４からの空気を散気管４５から散気して、空気の存在下、好気性微生物によって対象物質を酸化、分解する。接触酸化装置２４において酸化処理された被処理水は、加圧浮上分離装置２５に供給され、汚泥および処理水に分離される。
【００２７】
連続運転の際には、吸着剤投入装置２６から吸着剤を第２の吸着処理装置１９内に所定の投入速度で連続的に供給し、かつ第２の吸着処理装置１９から吸着剤を第１の吸着剤移送装置２８によって回収し、回収した吸着剤を所定の移送速度で第１の吸着処理装置１８に供給する。また、第１の吸着処理装置１８から吸着剤を第１の吸着剤回収装置３０によって所定の回収速度で回収する。また、吸着剤投入装置２７から吸着剤を第４の吸着処理装置２２内に所定の投入速度で連続的に供給し、かつ第４の吸着処理装置２２から吸着剤を第２の吸着剤移送装置２９によって回収し、回収した吸着剤を所定の移送速度で第３の吸着処理装置２１に供給する。また、第３の吸着処理装置２１から吸着剤を第２の吸着剤回収装置３１によって所定の回収速度で回収する。
【００２８】
ここで、吸着処理装置からの吸着剤の回収は、被処理水の混入量を極力減らすために、断続的に行うことが好ましい。第１の吸着処理装置１８および第３の吸着処理装置２１から回収された吸着剤を、吸着剤脱水装置にて脱水し、排水を二次調整槽１７に戻し、脱水された吸着剤を得る。脱水された吸着剤は、再利用または廃棄される。
【００２９】
吸着剤としては、対象物質が、アンモニア性窒素等の窒素化合物、色素、臭気物質などの場合は、合成ゼオライト、天然ゼオライト、人工ゼオライト等を用いることができる。また、対象物質が、リン化合物の場合は、無機凝集剤、酸化チタン、流用活性アルミナ、ケイ酸チタニウム等を用いることができる。吸着剤は、粒径が小さいほど表面積が増加するので、平均粒径が０．０１〜５０μｍのものが好ましい。
吸着剤の投入量（投入速度）は、吸着剤の吸着能、吸着処理後の被処理水に含まれる対象物質の目標濃度、水処理システムで得られる処理水に含まれる対象物質の目標濃度、生物処理手段の処理能力等によって適宜決定される。
【００３０】
吸着剤を凝集させるための凝集剤としては、無機凝集剤、有機高分子凝集剤、凝集助剤を用いることができる。中でも、使用済みのゼオライトを土壌に還元することが可能であり、廃棄物が発生しないことから、鉄系の無機凝集剤が好適である。
凝集剤の投入量（投入速度）は、無機凝集剤の場合、吸着剤であるゼオライトの沈降性、被処理水中のリン濃度、水処理システムで得られる処理水に含まれるリンの目標濃度等の条件によって、適宜決定すればよい。
有機高分子凝集剤は、無機凝集剤と併用することが好ましく、その投入量は無機凝集剤の場合と同様に適宜決定すればよい。
【００３１】
第１の沈殿槽１１および第２の沈殿槽１２における被処理水の滞留時間は、被処理水中の固形分の量に応じて適宜決定すればよい。
また、第１の調整槽１３および第２の調整槽１４における被処理水の温度、ｐＨ、および金属の添加量は、被処理水の性質により適宜決定すればよい。
また、二次調整槽１７における被処理水の温度は、被処理水の種類、吸着剤の種類、運転コストを鑑み、適宜決定すればよい。
【００３２】
第１の多段吸着処理装置２０および第２の多段吸着処理装置２３における被処理水の滞留時間は、被処理水中の対象物質の濃度、吸着剤の種類、量などの条件に応じて適宜決定すればよい。この滞留時間は、第２の被処理水供給装置３３による第１の吸着処理装置１８への被処理水の供給速度を調整することにより、調節することができる。
また、接触酸化装置２４における被処理水の滞留時間は、被処理水中の対象物質の濃度、接触酸化槽４２の容積などの条件に応じて適宜決定すればよい。
【００３３】
以上説明した水処理システムにあっては、第１の吸着処理装置１８および第２の吸着処理装置１９を１組とした第１の多段吸着処理装置２０と、第３の吸着処理装置２１および第４の吸着処理装置２２を１組とした第２の多段吸着処理装置２３とを具備しているので、以下の理由から、対象物質を高濃度、具体的にはアンモニウムイオンを１０００ｍｇ／Ｌ以上含む被処理水中の対象物質を低コストで除去できる。
【００３４】
アンモニウムイオン濃度が１０００ｍｇ／Ｌ以上の被処理水について、吸着剤の単位質量あたりの吸着平衡濃度および吸着量をもとに、多段化によるアンモニウムイオンの除去率を求めると、図６に示す１段処理では約６５％、図７に示す２段処理では同じ吸着剤量で約７２％、図８に示す３段処理では同じ吸着剤量で約７３％、図９に示す４段処理では同じ吸着剤量で約７３％となる。ここで、符号１は吸着処理装置、符号２は吸着剤移送装置、符号３は吸着剤回収装置、符号４は吸着剤投入装置である。したがって、後段側で使用した吸着剤を前段側に移送して再利用するタイプの多段吸着処理装置では、吸着剤の投入ポイントあたりの吸着処理装置を４段とするよりも、吸着剤の投入ポイントあたりの吸着処理装置を２段とし、この２段のものを２つ組み合わせた方が、吸着効率はよい。よって、２段２組とすることにより、吸着剤の投入ポイントは４段１組のものよりも多くなるが、全体の吸着剤の投入量は減らすことができる。
【００３５】
また、各多段吸着処理装置ごとに、後段側の吸着処理装置の被処理水に吸着剤を投入する吸着剤投入装置と、後段側の吸着処理装置で使用した吸着剤を前段側の吸着処理装置に移送する吸着剤移送装置とが設けられているので、以下の理由から、吸着剤のより効率的な使用が可能である。すなわち、吸着剤であるゼオライトは、アンモニウムイオンの濃度が低い方が、単位質量あたりのアンモニウムイオンの吸着量が多くなる傾向がある。よって、アンモニウムイオン濃度が比較的低い第２の吸着処理装置１９（第４の吸着処理装置２２）においてフレッシュな吸着剤を用いた方がアンモニウムイオンの吸着効率がよい。第２の吸着処理装置１２（第４の吸着処理装置２２）において使用された吸着剤の吸着能は、飽和に達していないので、これを第１の吸着処理装置１８（第３の吸着処理装置２１）にて再利用することが可能であり、吸着剤をより効率的に使用できる。
【００３６】
また、以上説明した水処理方法にあっては、被処理水中の対象物質を吸着剤に吸着させる吸着処理工程を２工程で１組とした多段吸着処理工程を２組以上有しているので、対象物質を高濃度に含む被処理水中の対象物質を低コストで除去できる。また、各多段吸着処理工程において、後工程側の吸着処理工程の被処理水に吸着剤を投入し、後段側の吸着処理工程で使用した吸着剤を前工程側の吸着処理工程で再利用しているので、吸着剤のより効率的な使用が可能である。
【００３７】
このような吸着処理装置（吸着処理工程）の組み合わせは、水素供与体成分（ＢＯＤ成分）に対する窒素成分の濃度が高すぎる排液の処理、例えば、アルコール排液を嫌気処理した後の被処理水の処理に好適である。また、このような吸着処理装置（吸着処理工程）の組み合わせによって処理された被処理水は、ＢＯＤ成分と窒素成分とのバランスがよく、生物処理に好適である。
【００３８】
（形態例２）
なお、本発明における生物処理手段は、上述の接触酸化法による装置（接触酸化装置２４）に限定はされず、標準活性汚泥法、膜分離式活性汚泥法、オキシデーションディチ法（ＯＤ法）などの硝化脱窒法による装置を用いることができる。以下、膜分離式活性汚泥法の装置を用いた例について説明する。
【００３９】
図２は、本発明の水処理システムの他の形態例を示す概略構成図であり、この水処理システムは、図１の水処理システムにおける接触酸化装置２４および加圧浮上分離装置２５の代わりに、浸漬型膜分離装置５０を設けたものである。
浸漬型膜分離装置５０は、被処理水の生物処理および固液分離を行うものであり、膜分離槽５１と、この中に配置された中空糸膜モジュール５２と、これに接続された吸引ポンプ５３と、膜分離槽５１に空気を供給するブロアポンプ５４と、中空糸膜モジュール５２の下方に配置され、ブロアポンプ５４からの空気を膜分離槽５１内に散気する散気管５５とを備えたものである。
中空糸膜モジュール５２は、略平行にシート状に配列された複数本の中空糸膜５６と、この両端部をその開口を維持したまま支持する２本の集水管５７とを備え、集水管５７の端部が吸引ポンプ５３に接続されたものである。
【００４０】
次に、図示例の水処理システムを用いた水処理方法について説明する。
吸着処理工程までは、形態例１の水処理システムを用いた場合と同じなので、説明を省略する。
第４の吸着処理装置２２において吸着処理された被処理水は、第４の吸着処理装置２２から溢れ、第４の吸着処理装置２２と浸漬型膜分離装置５０との高低差によって浸漬型膜分離装置５０に供給され、浸漬型膜分離装置５０において生物学的に処理され、固液分離される。具体的には、好気性微生物（汚泥）を含む被処理水にブロアポンプ５４からの空気を散気管５５から散気して、空気の存在下、好気性微生物によって対象物質を酸化、分解する。これと同時に、吸引ポンプ５３を作動させることにより、浸漬型膜分離装置５０の被処理水が中空糸膜５６を介して吸引され、その膜面で微生物や吸着剤等の固形物が捕らえられ、吸引ポンプ５３側から処理水が得られる。
【００４１】
（形態例３）
また、本発明における生物処理手段は、図３に示すように、浸漬型膜分離装置５０と、接触酸化装置２４および加圧浮上分離装置２５とを併用したものであっても構わない。
【００４２】
（その他の形態）
本発明の水処理システムは、図示例のものに限定はされず、吸着処理手段を２段で１組とした多段吸着処理手段を２組以上具備し、各多段吸着処理手段ごとに、後段側の吸着処理手段の被処理水に吸着剤を投入する吸着剤投入手段と、後段側の吸着処理手段で使用した吸着剤を前段側の吸着処理手段に移送する吸着剤移送手段とが設けられているものであればよい。
例えば、各多段吸着処理手段における２つの吸着処理手段は、図１に示すように隣り合っている必要はなく、図４に示すように、第３の吸着処理装置を２１を第１の吸着処理装置１８よりも前段側に設けてもよく、図５に示すように、第３の吸着処理装置を２１を、第１の吸着処理装置１８と第２の吸着処理装置１９との間に設けてもよい。
また、吸着処理手段を２段で１組とした多段吸着処理手段を３組以上設けてもよい。
【００４３】
沈殿槽は、図示例のように２段のものに限定はされず、その段数は、被処理水の種類、得られる処理水中の対象物質の目標濃度等に応じて適宜設計される。
また、調整槽は、図示例のように２段のものに限定はされず、その段数は、被処理水の種類、得られる処理水中の対象物質の目標濃度等に応じて適宜設計される。
また、嫌気処理手段は、図示例のように２段のものに限定はされず、その段数は、被処理水の種類、水量等に応じて適宜設計される。嫌気処理手段は、酸生成およびメタン生成を行うことが可能であることから、２段であることが好ましい。
【００４４】
また、各吸着処理装置間の被処理水の送液、および第４の吸着処理装置２２から接触酸化装置２４または浸漬型膜分離装置５０への被処理水の送液は、図示例では、各装置の高低差を利用した重力式で送液しているが、各装置間に送液ポンプを設けて、これで被処理水を送液しても構わない。
【００４５】
また、浸漬型膜分離装置５０においては、吸引ポンプ５３によって被処理水を中空糸膜５６を介して吸引し、処理水と固形分とを分離しているが、吸引ポンプ５３の代わりに、浸漬型膜分離装置５０よりも下方に貯水槽を設け、重力やサイフォン効果を利用して被処理水を中空糸膜５６を介して吸引し、この貯水槽に処理水を送液するようにしてもよい。吸引ポンプ５３を使用しないことによって、より低コストで処理水を得ることができる。
【００４６】
また、膜分離装置を用いる場合、これに用いる分離膜としては、中空糸膜以外に、平膜、管状膜、セラミック膜、金属膜等の各種分離膜を用いることができる。分離膜の材質も、固液分離が可能なものであればよく、高分子、金属、セラミックなどから選ぶことができる。
分離膜の平均孔径は、分離膜の二次側への吸着剤の流入を防ぐために、吸着剤の平均粒径よりも小さいことが好ましい。
また、加圧浮上分離装置２５の代わりに、常圧で固形分の分離が可能な分散空気法による装置を用いてもよい。
【００４７】
【実施例】
以下、具体的な実施例について説明する。
［実施例１］
図１に示す水処理システムを用いて、アンモニウムイオンを含む被処理水を処理した。第１の沈殿槽１１に供給する被処理水としては、大豆および米を原料とする発酵酒の製造工場からのアルコール発酵排液を用いた。第１の調整槽１３に供給する被処理水としては、米の洗浄液を用いた。アルコール発酵排液と米の洗浄液との比率（アルコール発酵排液：米の洗浄液）は、５：３とした。アルコール発酵排液および米の洗浄液の水質を表１に示す。
吸着剤としては、アンモニウムイオンを吸着する作用を持つゼオライト（平均粒径４．０μｍ）を用い、吸着剤を凝集させる凝集剤としては、ＰＦＣ（ポリ塩化鉄）を用いた。
【００４８】
【表１】

【００４９】
表中、ＣＯＤcr（ＣｈｅｍｉｃａｌＯｘｙｇｅｎＤｅｍａｎｄ）はニクロム酸カリウムを用いた測定法による化学的酸素要求量、ＳＳ（ＳｕｓｐｅｎｄｅｄＳｏｌｉｄｓ）は浮遊物質、ＶＳＳ（ＶｏｌａｔｉｌｅＳｕｓｐｅｎｄｅｄＳｏｌｉｄｓ）は溶解性浮遊物質、ＶＦＡ（ＶｏｌａｔｉｌｅＦａｔｔｙＡｃｉｄｓ）は揮発性脂肪酸量、Ｔ−Ｎは全窒素、Ｐはリン成分である。
【００５０】
水処理システムの運転条件は以下の通りである。
（１）処理量：４８Ｌ／日
（２）第１の沈殿槽１１における被処理水の滞留時間：２時間
（３）第２の沈殿槽１２における被処理水の滞留時間：１２時間
（４）第２の調整槽１４における調整後の被処理水のｐＨ：６．８−７．５
（５）第２の調整槽１４における調整後の被処理水の水温：３５℃
（６）第１の嫌気処理装置１５における被処理水の滞留時間：３６時間
（７）第２の嫌気処理装置１６における被処理水の滞留時間：２４時間
（８）二次調整槽１７における調整後の被処理水の水温：３０℃
（９）各多段吸着処理装置における被処理水の滞留時間：各１．５時間
（１０）第１の多段吸着処理装置２０におけるゼオライト濃度：３００００ｍｇ／Ｌ
（１１）第２の多段吸着処理装置２３におけるゼオライト濃度：７５００ｍｇ／Ｌ
（１２）第１の多段吸着処理装置２０へのＰＦＣ（ポリ塩化鉄）の投入は、被処理水中のＰＦＣ濃度が１０ｐｐｍとなるように連続的に行った。
（１３）第２の多段吸着処理装置２３へのＰＦＣ（ポリ塩化鉄）の投入は、被処理水中のＰＦＣ濃度が２．５ｐｐｍとなるように連続的に行った。
（１４）被接触酸化装置２４における被処理水の滞留時間：１４時間
（１５）加圧浮上分離装置２５における被処理水の滞留時間：４時間
【００５１】
以上の条件で、水処理システムを定常運転し、処理水を得た。処理水のＣＯＤcrは２７０ｍｇ／Ｌ、アンモニウム濃度は８．５ｍｇ／Ｌ、リン濃度は３ｍｇ／Ｌであった。
【００５２】
［実施例２］
水処理システムを図３に示すものに変更した以外は、実施例１と同様に被処理水を処理した。０．４μｍの分画を有する中空糸膜モジュールを用い、浸漬型膜分離装置５０における被処理水の滞留時間を２時間とした。
以上の条件で、水処理システムを定常運転し、処理水を得た。処理水のＣＯＤcrは２５０ｍｇ／Ｌ、アンモニウム濃度は８ｍｇ／Ｌ、リン濃度は２．５ｍｇ／Ｌであった。
【００５３】
［実施例３］
水処理システムを図２に示すものに変更した以外は、実施例１と同様に被処理水を処理した。０．４μｍの分画を有する中空糸膜モジュールを用い、浸漬型膜分離装置５０における被処理水の汚泥濃度を１００００ｍｇ／Ｌ、汚泥負荷を０．２、滞留時間を２４時間とした。
以上の条件で、水処理システムを定常運転し、処理水を得た。処理水のＣＯＤcrは２００ｍｇ／Ｌ、アンモニウム濃度は７ｍｇ／Ｌ、リン濃度は２ｍｇ／Ｌであった。
【００５４】
［実施例４］
各吸着処理装置の並び方を図４に示す並び方に変更し、条件を以下のように変更した以外は、実施例３と同様に被処理水を処理した。
（１０）第１の多段吸着処理装置２０におけるゼオライト濃度：７５００ｍｇ／Ｌ
（１１）第２の多段吸着処理装置２３におけるゼオライト濃度：３００００ｍｇ／Ｌ
（１２）第１の多段吸着処理装置２０へのＰＦＣ（ポリ塩化鉄）の投入は、被処理水中のＰＦＣ濃度が２．５ｐｐｍとなるように連続的に行った。
（１３）第２の多段吸着処理装置２３へのＰＦＣ（ポリ塩化鉄）の投入は、被処理水中のＰＦＣ濃度が１０ｐｐｍとなるように連続的に行った。
以上の条件で、水処理システムを定常運転し、処理水を得た。処理水のＣＯＤcrは２２０ｍｇ／Ｌ、アンモニウム濃度は７．５ｍｇ／Ｌ、リン濃度は２．５ｍｇ／Ｌであった。
【００５５】
【発明の効果】
以上説明したように、本発明の水処理システムは、被処理水中の対象物質を吸着剤に吸着させる吸着処理手段を２段で１組とした多段吸着処理手段を２組以上具備し、各多段吸着処理手段ごとに、後段側の吸着処理手段の被処理水に吸着剤を投入する吸着剤投入手段と、後段側の吸着処理手段で使用した吸着剤を前段側の吸着処理手段に移送する吸着剤移送手段とが設けられているものであるので、対象物質を高濃度に含む被処理水中の対象物質を低コストで除去できる。
【００５６】
また、本発明の水処理方法は、被処理水中の対象物質を吸着剤に吸着させる吸着処理工程を２工程で１組とした多段吸着処理工程を２組以上有し、各多段吸着処理工程において、後工程側の吸着処理工程の被処理水に吸着剤を投入し、後段側の吸着処理工程で使用した吸着剤を前工程側の吸着処理工程で再利用する方法であるので、対象物質を高濃度に含む被処理水中の対象物質を低コストで除去できる。
【図面の簡単な説明】
【図１】本発明の水処理システムの一例を示す概略構成図である。
【図２】本発明の水処理システムの他の例を示す概略構成図である。
【図３】本発明の水処理システムの他の例を示す概略構成図である。
【図４】本発明の水処理システムにおける吸着処理手段の並び方の他の例を示す概略構成図である。
【図５】本発明の水処理システムにおける吸着処理手段の並び方の他の例を示す概略構成図である。
【図６】本発明以外の水処理システムにおける吸着処理手段の一例を示す概略構成図である。
【図７】本発明以外の水処理システムにおける多段吸着処理手段の一例を示す概略構成図である。
【図８】本発明以外の水処理システムにおける多段吸着処理手段の他の例を示す概略構成図である。
【図９】本発明以外の水処理システムにおける多段吸着処理手段の他の例を示す概略構成図である。
【符号の説明】
１５第１の嫌気処理装置（嫌気処理手段）
１６第２の嫌気処理装置（嫌気処理手段）
１８第１の吸着処理装置（吸着処理手段）
１９第２の吸着処理装置（吸着処理手段）
２０第１の多段吸着処理装置（多段吸着処理手段）
２１第３の吸着処理装置（吸着処理手段）
２２第４の吸着処理装置（吸着処理手段）
２３第２の多段吸着処理装置（多段吸着処理手段）
２４接触酸化装置（生物処理手段）
２６第１の吸着剤投入装置（吸着剤投入手段）
２７第２の吸着剤投入装置（吸着剤投入手段）
２８第１の吸着剤移送装置（吸着剤移送手段）
２９第２の吸着剤移送装置（吸着剤移送手段）
５０浸漬型膜分離装置（生物処理手段）[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a water treatment system and a water treatment method, and in particular, a water treatment system and water for treating effluent containing nitrogen and phosphorus in high concentrations discharged from food factories, alcohol factories, livestock facilities, and the like. It relates to the processing method.
[0002]
[Prior art]
The effluent generated from the acetic acid fermentation process and the alcohol fermentation process is usually treated by an anaerobic treatment device such as the UASB method (upflow anaerobic sludge bed method), and the COD (chemical (Required oxygen demand) and recovery of useful methane gas. Although the COD is sufficiently reduced, the effluent subjected to anaerobic treatment still contains a nitrogen component having an ammonium ion concentration of 1000 mg / L or more and a high concentration phosphorus component. In recent years, it has become necessary to remove nitrogen components contained in high concentrations in alcoholic fermentation effluents as interest in environmental issues increases and regulations on effluents are tightened.
[0003]
Ammonia nitrogen (NH) contained in the drainage_Four -N) is a method for removing NH by nitrifying bacteria or nitrifying bacteria._Four ⁺NO₂ ^-, NO_Three ^-Biological nitrification and denitrification methods such as the standard activated sludge method are known, which are oxidized (nitrified) into nitrogen gas by denitrifying bacteria.
However, since the concentration of the nitrogen component with respect to the hydrogen donor component (BOD component) is too high, the wastewater that has been anaerobically treated by the UASB method or the like cannot be biologically treated by the standard activated sludge method. In order to perform biological treatment, it is necessary to adjust pH, add methanol, etc., and there is a problem that the treatment cost becomes high.
[0004]
As a method of removing ammonia nitrogen contained in the effluent, a method focusing on selective adsorption of ammonia nitrogen by zeolite is disclosed.
Japanese Patent Application Laid-Open No. 11-239785 discloses a method of using a substituted zeolite obtained by substituting a part of sodium ions and potassium ions of a zeolite with magnesium ions. According to this method, when the ammonium ion concentration in the drainage is 30 mg / L or less, stable treatment is possible. However, if the ammonium ion concentration exceeds 30 mg / L, particularly 1000 mg / L or more, the adsorption equilibrium is reached with a small amount of ammonium ions adsorbed per unit mass of the substituted zeolite. Cannot be used efficiently, and the amount of substituted zeolite added increases, resulting in high processing costs.
[0005]
[Patent Document 1]
JP-A-11-239785 (page 2-6)
[0006]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a water treatment system and a water treatment method that can remove a target substance in water to be treated containing the target substance at a high concentration at low cost.
[0007]
[Means for Solving the Problems]
  That is, the water treatment system of the present inventionAmmonium ionThere are two or more sets of multi-stage adsorption treatment means for adsorbing the adsorbent to the adsorbent, and for each multi-stage adsorption treatment means, the adsorbent is added to the water to be treated of the adsorption treatment means on the rear stage side. An adsorbent charging means for charging and an adsorbent transferring means for transferring the adsorbent used in the adsorption processing means on the rear stage side to the adsorption processing means on the front stage side are provided.
[0008]
  The water treatment system of the present invention preferably includes a biological treatment means for biologically treating the water to be treated treated by the adsorption treatment means.
  In addition, the water treatment system of the present invention preferably includes an anaerobic treatment means for treating the water to be treated with anaerobic bacteria on the upstream side of the multistage adsorption treatment means.
  The adsorbent is preferably a zeolite.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below.
(Example 1)
FIG. 1 is a schematic configuration diagram illustrating an example of a water treatment system according to the present invention. This water treatment system includes a first settling tank 11 and a second settling tank 12 for precipitating solids in the water to be treated, and a first adjustment tank 13 and a second settling tank for adjusting the water temperature, pH and the like of the water to be treated. The adjustment tank 14, the first anaerobic treatment device 15 and the second anaerobic treatment device 16 (anaerobic treatment means) for treating the water to be treated with anaerobic bacteria, and the water temperature, pH, water amount, etc. of the water to be treated are adjusted. A first multi-stage adsorption treatment apparatus 20 (second adsorption tank 17 and a first adsorption treatment apparatus 18 and a second adsorption treatment apparatus 19 (adsorption treatment means) for adsorbing the target substance in the water to be treated to the adsorbent. Multi-stage adsorption processing means), a second multi-stage adsorption processing apparatus 23 (multi-stage adsorption processing means) comprising a third adsorption processing apparatus 21 and a fourth adsorption processing apparatus 22 (adsorption processing means), and the adsorption processing apparatus. Biological treatment of treated water Adsorbent in the water to be treated of the catalytic oxidation apparatus 24 (biological treatment means), the pressurized flotation separation apparatus 25 that performs solid-liquid separation of the water to be treated that has been treated by the contact oxidation apparatus 13, and the second adsorption treatment apparatus 19 First adsorbent input device 26 (adsorbent input means) and second adsorbent input device 27 (adsorbent input means) for supplying adsorbent to the water to be treated of the fourth adsorption treatment device 22 And the first adsorbent transfer device 28 (adsorbent transfer means) for transferring the adsorbent used in the second adsorption treatment device 19 to the first adsorption treatment device 18 and the fourth adsorption treatment device 22. The second adsorbent transfer device 29 (adsorbent transfer means) for transferring the adsorbent adsorbed to the third adsorption treatment device 21 and the first adsorbent for recovering the adsorbent used in the first adsorption treatment device 18 A first unit for recovering the adsorbent used in the recovery device 30 and the third adsorption processing device 21. The adsorbent recovery device 31, the first treated water supply device 32 for feeding the treated water from the second adjustment tank 14 to the first anaerobic treatment device 15, and the first adjustment water from the secondary adjustment tank 17. A second treated water supply device 33 for feeding treated water to the adsorption treatment device 18 is provided and is schematically configured.
[0012]
The first sedimentation tank 11 is a tank for mainly precipitating relatively large solids having a particle diameter of 1 mm or more, and the second precipitation tank 12 is mainly composed of relatively small solids having a particle diameter of 1 mm or less. It is a tank for making it settle.
The 1st adjustment tank 13 and the 2nd adjustment tank 14 adjust water temperature, pH, water quantity, etc. of to-be-processed water. Moreover, it is a tank for adding the trace amount metal which is a nutrient source of the anaerobic bacteria in the anaerobic processing apparatus of a back | latter stage.
[0013]
The anaerobic treatment means performs energy (methane gas) recovery and COD reduction. Specifically, the first anaerobic treatment device 15 treats the treated water with anaerobic bacteria to mainly generate acid, and the second anaerobic treatment device 16 treats the treated water with anaerobic bacteria. Further processing mainly produces methane.
As the anaerobic treatment device, an upward flow anaerobic treatment device such as a device based on the UASB method (upward flow anaerobic sludge bed method) or a device based on the EGSB method (expanded granule sludge bed method) can be used.
[0014]
The first adsorption treatment device 18 includes an adsorption treatment tank 34 having a portion for bringing the water to be treated into contact with the adsorbent and a portion for causing the adsorbent to settle and separate, and agitation for stirring the water to be treated in the adsorption treatment tank 34. The apparatus 35 is provided.
Similarly, the second adsorption treatment device 19 includes an adsorption treatment tank 36 and a stirring device 37, and the water to be treated treated by the first adsorption treatment device 18 is second adsorbed by gravity. It is installed at a position lower than the first adsorption processing device 18 so as to flow to the processing device 19.
[0015]
Similarly, the third adsorption treatment device 21 includes an adsorption treatment tank 38 and a stirring device 39, and the water to be treated treated by the second adsorption treatment device 19 is subjected to the third adsorption by gravity. It is installed at a position lower than the second adsorption processing device 19 so as to flow to the processing device 21.
Similarly, the fourth adsorption treatment device 22 includes an adsorption treatment tank 40 and a stirring device 41, and the water to be treated treated by the third adsorption treatment device 21 is subjected to the fourth adsorption by gravity. It is installed at a position lower than the third adsorption processing device 21 so as to flow to the processing device 22.
[0016]
The contact oxidation device 24 includes a contact oxidation tank 42, a contact material 43 disposed in the contact oxidation tank 42, a blower pump 44 that supplies air to the contact oxidation tank 42, and a contact material 43. An air diffuser 45 is disposed below and diffuses air from the blower pump 44 into the contact oxidation tank 42.
The pressurized flotation separation device 25 floats sludge in the water to be treated by fine bubbles generated in the water to be treated by pressurization, and separates the water to be treated into sludge and treated water. Pressurizing means (not shown) such as a pressurizing pump and a pressurizing tank for pressurizing the water to be treated in the tank 46 and the solid-liquid separation tank 46, and scraping means 47 such as a scraper for scraping off the sludge that floats up. It is equipped with.
[0017]
The first adsorbent charging device 26 is for charging the adsorbent into the second adsorption processing device 19 on the rear stage of the two adsorption processing devices constituting the first multistage adsorption processing device 20. A storage container (not shown) for storing the agent, an input port (not shown) for supplying the adsorbent to the second adsorption processing device 19, and an adsorbent input speed (per hour) provided at the input port And an adjustment mechanism (not shown) that adjusts the amount of input).
Similarly, the second adsorbent charging device 27 is for charging the adsorbent into the fourth adsorption processing device 22 on the rear side of the two adsorption processing devices constituting the second multistage adsorption processing device 23. A storage container (not shown) for storing the adsorbent, an input port (not shown) for supplying the adsorbent to the fourth adsorption processing device 22, and an adsorbent input speed provided at the input port; And an adjusting mechanism (not shown) for adjusting (the amount charged per hour).
[0018]
The first adsorbent transfer device 28 collects the adsorbent aggregated and settled by the flocculant at the bottom of the adsorption treatment tank 36 of the second adsorption treatment device 19 together with some water to be treated. This is supplied to the device 18.
The second adsorbent transfer device 29 collects the adsorbent aggregated and settled with the flocculant at the bottom of the adsorption treatment tank 40 of the fourth adsorption treatment device 22 together with some water to be treated, and performs the third adsorption treatment. This is supplied to the device 21.
As these adsorbent transfer devices, for example, a screw pump, a snake pump, a gear pump, a cascade pump, a tube pump, and the like can be appropriately selected according to the viscosity, concentration, amount, etc. of the adsorbent.
[0019]
The first adsorbent recovery device 30 recovers the adsorbent settled on the bottom of the adsorption treatment tank 34 of the first adsorption treatment device 18 together with some water to be treated, and transfers it to an adsorbent dehydration device (not shown). Is.
The second adsorbent recovery device 31 recovers the adsorbent settled on the bottom of the adsorption treatment tank 38 of the third adsorption treatment device 21 together with some water to be treated, and transfers it to an adsorbent dewatering device (not shown). Is.
These adsorbent recovery devices can be appropriately selected from screw pumps, snake pumps, gear pumps, cascade pumps, tube pumps, etc., depending on the viscosity, concentration, amount, etc. of the adsorbent.
[0020]
The adsorbent dewatering device (not shown) dehydrates water from the adsorbent collected from the adsorption processing device and returns the drainage by dehydration to the secondary adjustment tank 17 to obtain the dehydrated adsorbent. As the adsorbent dehydrating device, a roll dehydrating dehydrator, a pressure dehydrating dehydrator, a vacuum dehydrating dehydrator, or the like can be used.
Further, in the first multi-stage adsorption processing apparatus 20 and the second multi-stage adsorption processing apparatus 23, the coagulant feeding apparatus for feeding the coagulant to the adsorption processing apparatus on the rear stage among the two adsorption processing apparatuses constituting each of them. (Not shown) shall be attached.
[0021]
Next, a water treatment method using the illustrated water treatment system will be described.
Before starting the operation of this water treatment system, first, anaerobic bacteria are inoculated into the first anaerobic treatment device 15 and the second anaerobic treatment device 16 and cultured. Moreover, seed sludge is planted in the contact oxidation apparatus 24, and aerobic microorganisms are made to adhere to the contact material 43 which is a support | carrier.
Furthermore, after a predetermined amount of adsorbent is charged into the second adsorption processing device 19 from the adsorbent charging device 26 and subjected to the adsorption processing for a predetermined time in the second adsorption processing device 19, the first adsorbent transfer device 28. And the adsorbent that has been aggregated and settled by the flocculant at the bottom of the adsorption treatment tank 36 of the second adsorption treatment device 19 is collected together with some water to be treated, and a predetermined amount of adsorbent is collected in the first adsorption treatment. Supply to device 18. Similarly, after a predetermined amount of adsorbent is charged into the fourth adsorption processing device 22 from the second adsorbent charging device 27 and the fourth adsorption processing device 22 performs the adsorption processing for a predetermined time, the second adsorption is performed. The adsorbent transfer device 29 is actuated to collect the adsorbent that has been agglomerated and settled with the flocculant at the bottom of the adsorption treatment tank 40 of the fourth adsorption treatment device 22 together with some water to be treated. 3 is supplied to the adsorption processing device 21.
[0022]
Thus, after adjusting the conditions of each apparatus, a continuous operation is started.
First, waste liquid (water to be treated) such as alcohol fermentation is introduced into the first sedimentation tank 11 and then into the second sedimentation tank 12, and the solid content in the water to be treated is removed by precipitation.
The water to be treated from which the solid matter has been removed by precipitation is supplied to the first adjustment tank 13 and then to the second adjustment tank 14, and the water temperature, pH and the like are adjusted. Moreover, in the 2nd adjustment tank 14, the trace amount metal which is a nutrient source of anaerobic bacteria is added to to-be-processed water.
When the solid content is not contained in the water to be treated, the water to be treated may be supplied directly to the first adjustment tank 13 without passing through the first precipitation tank 11 and the second precipitation tank 12.
[0023]
The water to be treated whose water temperature, pH and the like are adjusted is sent to the first anaerobic treatment device 15 by the first treated water supply device 32 and treated with anaerobic bacteria in the first anaerobic treatment device 15. The acid is mainly produced. Subsequently, the water to be treated is further treated with anaerobic bacteria in the second anaerobic treatment device 16, where methane is mainly produced.
The water to be treated that has been subjected to anaerobic treatment is sent to the secondary adjustment tank 17, and the water temperature, pH, amount of water, and the like are adjusted.
[0024]
The treated water continuously supplied from the secondary adjustment tank 17 to the first adsorption treatment device 18 by the second treated water supply device 33 first comes into contact with the adsorbent in the first adsorption treatment device 18. The target substance in the for-treatment water is adsorbed by the adsorbent. The water to be treated that has been subjected to the adsorption treatment in the first adsorption treatment device 18 overflows from the first adsorption treatment device 18, and the second adsorption due to the height difference between the first adsorption treatment device 18 and the second adsorption treatment device 19. It is supplied to the adsorption treatment device 12 and comes into contact with the adsorbent in the second adsorption treatment device 19 so that the target substance in the for-treatment water is adsorbed by the adsorbent.
[0025]
The water to be treated that has been subjected to the adsorption treatment in the second adsorption treatment device 19 overflows from the second adsorption treatment device 19, and the third adsorption treatment device 19 and the third adsorption treatment device 21 cause a third difference. The material is supplied to the adsorption treatment device 21, contacts the adsorbent in the third adsorption treatment device 21, and the target substance in the for-treatment water is adsorbed by the adsorbent. The water to be treated which has been subjected to the adsorption treatment in the third adsorption treatment device 21 overflows from the third adsorption treatment device 21, and the fourth adsorption treatment device 21 and the fourth adsorption treatment device 22 cause a fourth difference. The material is supplied to the adsorption treatment device 22, contacts the adsorbent in the fourth adsorption treatment device 22, and the target substance in the for-treatment water is adsorbed by the adsorbent.
[0026]
The water to be treated that has been subjected to the adsorption treatment in the fourth adsorption treatment device 22 overflows from the fourth adsorption treatment device 22 and is supplied to the contact oxidation device 24 due to the height difference between the fourth adsorption treatment device 22 and the contact oxidation device 24. And biologically processed in the catalytic oxidizer 24. Specifically, air from the blower pump 44 is diffused from the air diffuser 45 to the contact material 43 to which aerobic microorganisms (sludge) adhere, and the target substance is oxidized and decomposed by the aerobic microorganisms in the presence of air. The treated water oxidized in the contact oxidation device 24 is supplied to the pressurized flotation separation device 25 and separated into sludge and treated water.
[0027]
During continuous operation, the adsorbent is continuously supplied from the adsorbent input device 26 into the second adsorption processing device 19 at a predetermined input speed, and the adsorbent is supplied from the second adsorption processing device 19 to the first adsorbent. The adsorbent transfer device 28 collects the recovered adsorbent and supplies the recovered adsorbent to the first adsorption processing device 18 at a predetermined transfer speed. Further, the adsorbent is recovered from the first adsorption processing device 18 by the first adsorbent recovery device 30 at a predetermined recovery rate. Further, the adsorbent is continuously supplied from the adsorbent input device 27 into the fourth adsorption processing device 22 at a predetermined input speed, and the adsorbent is supplied from the fourth adsorption processing device 22 to the second adsorbent transfer device. The recovered adsorbent is supplied to the third adsorption processing device 21 at a predetermined transfer speed. Further, the adsorbent is recovered from the third adsorption processing device 21 by the second adsorbent recovery device 31 at a predetermined recovery rate.
[0028]
Here, the collection of the adsorbent from the adsorption processing apparatus is preferably performed intermittently in order to reduce the amount of water to be treated as much as possible. The adsorbent recovered from the first adsorption processing device 18 and the third adsorption processing device 21 is dehydrated by the adsorbent dehydrating device, and the waste water is returned to the secondary adjustment tank 17 to obtain the dehydrated adsorbent. The desorbed adsorbent is reused or discarded.
[0029]
As the adsorbent, synthetic zeolite, natural zeolite, artificial zeolite or the like can be used when the target substance is a nitrogen compound such as ammoniacal nitrogen, a dye, or an odor substance. When the target substance is a phosphorus compound, an inorganic flocculant, titanium oxide, diverted activated alumina, titanium silicate, or the like can be used. Since the surface area of the adsorbent increases as the particle size decreases, it is preferable that the adsorbent has an average particle size of 0.01 to 50 μm.
The amount of adsorbent input (input speed) is the adsorption capacity of the adsorbent, the target concentration of the target substance contained in the treated water after the adsorption treatment, the target concentration of the target substance contained in the treated water obtained by the water treatment system, It is determined appropriately depending on the processing capacity of the biological treatment means.
[0030]
As the aggregating agent for aggregating the adsorbent, an inorganic aggregating agent, an organic polymer aggregating agent, and an aggregating aid can be used. Among them, iron-based inorganic flocculants are suitable because spent zeolite can be reduced to soil and no waste is generated.
In the case of an inorganic flocculant, the amount of flocculant input (input speed) is such as the sedimentation property of zeolite as an adsorbent, the phosphorus concentration in the water to be treated, and the target concentration of phosphorus contained in the treated water obtained by the water treatment system. What is necessary is just to determine suitably according to conditions.
The organic polymer flocculant is preferably used in combination with an inorganic flocculant, and the amount of the organic polymer flocculant may be appropriately determined as in the case of the inorganic flocculant.
[0031]
What is necessary is just to determine suitably the residence time of the to-be-processed water in the 1st settling tank 11 and the 2nd settling tank 12 according to the quantity of solid content in to-be-processed water.
Moreover, what is necessary is just to determine suitably the temperature of the to-be-processed water in the 1st adjustment tank 13 and the 2nd adjustment tank 14, pH, and the addition amount of a metal by the property of to-be-processed water.
Moreover, what is necessary is just to determine the temperature of the to-be-processed water in the secondary adjustment tank 17 suitably in view of the kind of to-be-treated water, the kind of adsorbent, and the operating cost.
[0032]
The residence time of the water to be treated in the first multistage adsorption treatment apparatus 20 and the second multistage adsorption treatment apparatus 23 is appropriately determined according to conditions such as the concentration of the target substance in the treatment water, the type and amount of the adsorbent. That's fine. This residence time can be adjusted by adjusting the supply rate of the water to be treated to the first adsorption treatment device 18 by the second treated water supply device 33.
Further, the residence time of the water to be treated in the contact oxidation device 24 may be appropriately determined according to conditions such as the concentration of the target substance in the water to be treated and the volume of the contact oxidation tank 42.
[0033]
In the water treatment system described above, the first multi-stage adsorption treatment device 20 including the first adsorption treatment device 18 and the second adsorption treatment device 19, the third adsorption treatment device 21, and the first adsorption treatment device 19 are combined. The second multi-stage adsorption treatment device 23 is composed of four adsorption treatment devices 22 as a set. Therefore, the target substance contains a high concentration, specifically, contains 1000 mg / L or more of ammonium ions for the following reasons. The target substance in the treated water can be removed at low cost.
[0034]
For the water to be treated having an ammonium ion concentration of 1000 mg / L or more, the removal rate of ammonium ions by multi-stage formation based on the adsorption equilibrium concentration and the adsorption amount per unit mass of the adsorbent is obtained as shown in FIG. About 65% in the process, about 72% with the same adsorbent amount in the two-stage process shown in FIG. 7, about 73% with the same adsorbent quantity in the three-stage process shown in FIG. 8, and the same adsorption in the four-stage process shown in FIG. The amount is about 73%. Here, reference numeral 1 is an adsorption processing apparatus, reference numeral 2 is an adsorbent transfer apparatus, reference numeral 3 is an adsorbent recovery apparatus, and reference numeral 4 is an adsorbent input apparatus. Therefore, in the multi-stage adsorption processing apparatus of the type in which the adsorbent used on the rear stage side is transferred to the front stage side and reused, the adsorbent input point is more than the four adsorption processing apparatuses per adsorbent input point. Adsorption efficiency is better when the number of the per unit adsorption processing apparatus is two stages and two of these two stages are combined. Therefore, by using two sets of two stages, the adsorbent charging point becomes larger than that of the four stages of one set, but the total amount of adsorbent input can be reduced.
[0035]
In addition, for each multi-stage adsorption treatment apparatus, an adsorbent input apparatus for introducing the adsorbent into the water to be treated of the latter-stage adsorption treatment apparatus, and an adsorbent used in the latter-stage adsorption treatment apparatus for the former-stage adsorption treatment apparatus. Therefore, the adsorbent can be used more efficiently for the following reasons. That is, zeolite that is an adsorbent tends to increase the amount of adsorption of ammonium ions per unit mass when the concentration of ammonium ions is low. Therefore, the adsorption efficiency of ammonium ions is better when a fresh adsorbent is used in the second adsorption treatment device 19 (fourth adsorption treatment device 22) having a relatively low ammonium ion concentration. Since the adsorption capacity of the adsorbent used in the second adsorption treatment device 12 (fourth adsorption treatment device 22) has not reached saturation, this is referred to as the first adsorption treatment device 18 (third adsorption treatment device). 21), and the adsorbent can be used more efficiently.
[0036]
Moreover, in the water treatment method demonstrated above, since it has two or more sets of the multistage adsorption treatment process which made the adsorption treatment process to adsorb | suck the target substance in to-be-processed water to adsorption agent in two steps, The target substance in the water to be treated containing the target substance at a high concentration can be removed at a low cost. Also, in each multi-stage adsorption treatment process, an adsorbent is introduced into the water to be treated in the adsorption process step on the post-process side, and the adsorbent used in the adsorption process step on the post-stage side is reused in the adsorption treatment process on the pre-process side. Therefore, more efficient use of the adsorbent is possible.
[0037]
Such a combination of adsorption treatment devices (adsorption treatment steps) is a treatment of wastewater in which the concentration of the nitrogen component relative to the hydrogen donor component (BOD component) is too high, for example, treated water after anaerobic treatment of alcohol wastewater. It is suitable for the process. Moreover, the to-be-processed water processed by the combination of such an adsorption treatment apparatus (adsorption treatment process) has a good balance of a BOD component and a nitrogen component, and is suitable for biological treatment.
[0038]
(Example 2)
In addition, the biological treatment means in this invention is not limited to the apparatus (contact oxidation apparatus 24) by the above-mentioned contact oxidation method, Standard activated sludge method, membrane separation type activated sludge method, oxidation ditch method (OD method) An apparatus using a nitrification denitrification method such as can be used. Hereinafter, an example using the apparatus of the membrane separation type activated sludge method will be described.
[0039]
FIG. 2 is a schematic configuration diagram showing another embodiment of the water treatment system of the present invention. This water treatment system is used in place of the contact oxidation device 24 and the pressure flotation separation device 25 in the water treatment system of FIG. A submerged membrane separation apparatus 50 is provided.
The submerged membrane separation device 50 performs biological treatment and solid-liquid separation of water to be treated, and includes a membrane separation tank 51, a hollow fiber membrane module 52 disposed therein, and a suction pump connected thereto. 53, a blower pump 54 for supplying air to the membrane separation tank 51, and a diffuser pipe 55 which is disposed below the hollow fiber membrane module 52 and diffuses the air from the blower pump 54 into the membrane separation tank 51. It is.
The hollow fiber membrane module 52 includes a plurality of hollow fiber membranes 56 arranged substantially in parallel in a sheet shape, and two water collecting pipes 57 that support both ends of the hollow fiber membranes 56 while maintaining their openings. Is connected to the suction pump 53.
[0040]
Next, a water treatment method using the illustrated water treatment system will be described.
Since the process up to the adsorption process is the same as that in the case of using the water treatment system of the first embodiment, the description is omitted.
The water to be treated that has been subjected to the adsorption treatment in the fourth adsorption treatment device 22 overflows from the fourth adsorption treatment device 22, and the immersion type membrane separation is caused by the height difference between the fourth adsorption treatment device 22 and the immersion type membrane separation device 50. It is supplied to the apparatus 50, biologically processed in the submerged membrane separation apparatus 50, and solid-liquid separated. Specifically, air from the blower pump 54 is diffused into the water to be treated containing aerobic microorganisms (sludge) from the aeration pipe 55, and the target substance is oxidized and decomposed by the aerobic microorganisms in the presence of air. At the same time, by operating the suction pump 53, the water to be treated of the submerged membrane separator 50 is sucked through the hollow fiber membrane 56, and solids such as microorganisms and adsorbents are captured on the membrane surface, Treated water is obtained from the suction pump 53 side.
[0041]
(Example 3)
Moreover, the biological treatment means in the present invention may be a combination of a submerged membrane separation device 50, a contact oxidation device 24, and a pressurized flotation separation device 25 as shown in FIG.
[0042]
(Other forms)
The water treatment system of the present invention is not limited to the example shown in the figure, and includes at least two sets of multi-stage adsorption treatment means in which two sets of adsorption treatment means are provided, and each multi-stage adsorption treatment means has a rear stage side. An adsorbent input means for introducing adsorbent into the water to be treated of the adsorption treatment means, and an adsorbent transfer means for transferring the adsorbent used in the adsorption treatment means on the rear stage to the adsorption treatment means on the front stage. If it is,
For example, the two adsorption processing units in each multi-stage adsorption processing unit do not have to be adjacent to each other as shown in FIG. 1, but the third adsorption processing device 21 is replaced with the first adsorption processing as shown in FIG. The third adsorption processing device 21 may be provided between the first adsorption treatment device 18 and the second adsorption treatment device 19 as shown in FIG. Also good.
Further, three or more sets of multi-stage adsorption processing means in which two sets of adsorption processing means are provided may be provided.
[0043]
The settling tank is not limited to a two-stage tank as in the illustrated example, and the number of stages is appropriately designed according to the type of water to be treated, the target concentration of the target substance in the obtained treated water, and the like.
In addition, the adjustment tank is not limited to a two-stage tank as in the illustrated example, and the number of stages is appropriately designed according to the type of water to be treated, the target concentration of the target substance in the obtained treated water, and the like.
Further, the anaerobic treatment means is not limited to two stages as in the illustrated example, and the number of stages is appropriately designed according to the type of water to be treated, the amount of water, and the like. The anaerobic treatment means is preferably two-stage because it can perform acid generation and methane generation.
[0044]
In addition, in the illustrated example, the water to be treated between the adsorption treatment devices and the water to be treated from the fourth adsorption treatment device 22 to the contact oxidation device 24 or the submerged membrane separation device 50 are Although liquid feeding is performed by gravity using the difference in height of the apparatus, a liquid feed pump may be provided between the apparatuses, and the water to be treated may be fed by this.
[0045]
In the submerged membrane separation apparatus 50, the water to be treated is sucked through the hollow fiber membrane 56 by the suction pump 53 to separate the treated water from the solid content. A water storage tank is provided below the mold membrane separation device 50, and the water to be treated is sucked through the hollow fiber membrane 56 using gravity or siphon effect, and the treated water is fed to the water storage tank. Good. By not using the suction pump 53, treated water can be obtained at a lower cost.
[0046]
Moreover, when using a membrane separation apparatus, as a separation membrane used for this, various separation membranes, such as a flat membrane, a tubular membrane, a ceramic membrane, a metal membrane, can be used besides a hollow fiber membrane. The material of the separation membrane may be any material that can be solid-liquid separated, and can be selected from polymers, metals, ceramics, and the like.
In order to prevent the adsorbent from flowing into the secondary side of the separation membrane, the average pore size of the separation membrane is preferably smaller than the average particle size of the adsorbent.
Further, instead of the pressurized flotation separation device 25, a device by a dispersion air method capable of separating a solid content at normal pressure may be used.
[0047]
【Example】
Specific examples will be described below.
[Example 1]
The water to be treated containing ammonium ions was treated using the water treatment system shown in FIG. As the water to be treated to be supplied to the first settling tank 11, alcohol fermentation effluent from a fermented liquor manufacturing factory using soybean and rice as raw materials was used. As the water to be treated supplied to the first adjustment tank 13, a rice cleaning liquid was used. The ratio of alcohol fermentation effluent to rice washing liquid (alcohol fermentation effluent: rice washing liquid) was 5: 3. Table 1 shows the water quality of the alcohol fermentation effluent and the rice washing liquid.
As the adsorbent, zeolite having an action of adsorbing ammonium ions (average particle size: 4.0 μm) was used, and PFC (polyiron chloride) was used as the flocculant for aggregating the adsorbent.
[0048]
[Table 1]

[0049]
In the table, CODcr (Chemical Oxygen Demand) is the chemical oxygen demand according to the measurement method using potassium dichromate, SS (Suspended Solids) is the suspended solid, VSS (Volatile Suspended Solids) is the soluble suspended matter, VFA (VolatileFidile Fatty) ) Is the amount of volatile fatty acid, TN is total nitrogen, and P is a phosphorus component.
[0050]
The operating conditions of the water treatment system are as follows.
(1) Processing volume: 48L / day
(2) Residence time of water to be treated in the first sedimentation tank 11: 2 hours
(3) Residence time of the water to be treated in the second sedimentation tank 12: 12 hours
(4) pH of the water to be treated after adjustment in the second adjustment tank 14: 6.8-7.5
(5) Water temperature of the treated water after adjustment in the second adjustment tank 14: 35 ° C
(6) Residence time of treated water in the first anaerobic treatment device 15: 36 hours
(7) Residence time of the water to be treated in the second anaerobic treatment device 16: 24 hours
(8) Temperature of water to be treated after adjustment in the secondary adjustment tank 17: 30 ° C
(9) Retention time of water to be treated in each multistage adsorption treatment apparatus: 1.5 hours each
(10) Zeolite concentration in the first multistage adsorption treatment apparatus 20: 30000 mg / L
(11) Zeolite concentration in the second multistage adsorption treatment apparatus 23: 7500 mg / L
(12) The introduction of PFC (polyiron chloride) into the first multistage adsorption treatment apparatus 20 was continuously performed so that the PFC concentration in the water to be treated was 10 ppm.
(13) The introduction of PFC (polyiron chloride) into the second multistage adsorption treatment apparatus 23 was continuously performed so that the PFC concentration in the water to be treated was 2.5 ppm.
(14) Residence time of water to be treated in the contacted oxidizer 24: 14 hours
(15) Residence time of the water to be treated in the pressure flotation separator 25: 4 hours
[0051]
Under the above conditions, the water treatment system was steadily operated to obtain treated water. The CODcr of the treated water was 270 mg / L, the ammonium concentration was 8.5 mg / L, and the phosphorus concentration was 3 mg / L.
[0052]
[Example 2]
The treated water was treated in the same manner as in Example 1 except that the water treatment system was changed to that shown in FIG. The hollow fiber membrane module which has a 0.4 micrometer fraction was used, and the residence time of the to-be-processed water in the immersion type membrane separator 50 was 2 hours.
Under the above conditions, the water treatment system was steadily operated to obtain treated water. The CODcr of the treated water was 250 mg / L, the ammonium concentration was 8 mg / L, and the phosphorus concentration was 2.5 mg / L.
[0053]
[Example 3]
The treated water was treated in the same manner as in Example 1 except that the water treatment system was changed to that shown in FIG. A hollow fiber membrane module having a fraction of 0.4 μm was used, the sludge concentration in the submerged membrane separator 50 was 10,000 mg / L, the sludge load was 0.2, and the residence time was 24 hours.
Under the above conditions, the water treatment system was steadily operated to obtain treated water. The CODcr of the treated water was 200 mg / L, the ammonium concentration was 7 mg / L, and the phosphorus concentration was 2 mg / L.
[0054]
[Example 4]
The water to be treated was treated in the same manner as in Example 3 except that the arrangement of the adsorption treatment apparatuses was changed to the arrangement shown in FIG. 4 and the conditions were changed as follows.
(10) Zeolite concentration in the first multistage adsorption treatment apparatus 20: 7500 mg / L
(11) Zeolite concentration in the second multistage adsorption treatment apparatus 23: 30000 mg / L
(12) The introduction of PFC (polyiron chloride) into the first multistage adsorption treatment apparatus 20 was continuously performed so that the PFC concentration in the water to be treated was 2.5 ppm.
(13) The introduction of PFC (polyiron chloride) into the second multistage adsorption treatment apparatus 23 was continuously performed so that the PFC concentration in the water to be treated was 10 ppm.
Under the above conditions, the water treatment system was steadily operated to obtain treated water. The CODcr of the treated water was 220 mg / L, the ammonium concentration was 7.5 mg / L, and the phosphorus concentration was 2.5 mg / L.
[0055]
【The invention's effect】
As described above, the water treatment system of the present invention includes two or more sets of multistage adsorption treatment means in which two sets of adsorption treatment means for adsorbing the target substance in the water to be treated to the adsorbent, each multistage. For each adsorption processing means, an adsorbent input means for introducing the adsorbent into the water to be treated of the adsorption processing means on the rear stage side, and an adsorption for transferring the adsorbent used in the adsorption processing means on the rear stage side to the adsorption processing means on the front stage side Since the agent transfer means is provided, the target substance in the water to be treated containing the target substance at a high concentration can be removed at low cost.
[0056]
In addition, the water treatment method of the present invention has two or more multi-stage adsorption treatment steps in which the adsorption treatment step for adsorbing the target substance in the treated water to the adsorbent is made into two sets, and each multi-stage adsorption treatment step. Since the adsorbent is introduced into the water to be treated in the adsorption process on the subsequent process side and the adsorbent used in the adsorption process on the subsequent stage is reused in the adsorption process on the previous process side, The target substance in the water to be treated contained in a high concentration can be removed at low cost.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an example of a water treatment system of the present invention.
FIG. 2 is a schematic configuration diagram showing another example of the water treatment system of the present invention.
FIG. 3 is a schematic configuration diagram showing another example of the water treatment system of the present invention.
FIG. 4 is a schematic configuration diagram showing another example of how the adsorption treatment means are arranged in the water treatment system of the present invention.
FIG. 5 is a schematic configuration diagram showing another example of how the adsorption treatment means are arranged in the water treatment system of the present invention.
FIG. 6 is a schematic configuration diagram illustrating an example of an adsorption treatment unit in a water treatment system other than the present invention.
FIG. 7 is a schematic configuration diagram showing an example of multistage adsorption processing means in a water treatment system other than the present invention.
FIG. 8 is a schematic configuration diagram showing another example of the multistage adsorption processing means in the water treatment system other than the present invention.
FIG. 9 is a schematic configuration diagram showing another example of the multistage adsorption treatment means in the water treatment system other than the present invention.
[Explanation of symbols]
15 First anaerobic treatment device (anaerobic treatment means)
16 Second anaerobic treatment device (anaerobic treatment means)
18 1st adsorption processing device (adsorption processing means)
19 Second adsorption processing device (adsorption processing means)
20 1st multistage adsorption processing apparatus (multistage adsorption processing means)
21 3rd adsorption processing apparatus (adsorption processing means)
22 4th adsorption processing apparatus (adsorption processing means)
23 Second multi-stage adsorption processing device (multi-stage adsorption processing means)
24 Catalytic oxidation equipment (biological treatment means)
26 1st adsorbent input device (adsorbent input means)
27 Second adsorbent charging device (adsorbent charging means)
28 First adsorbent transfer device (adsorbent transfer means)
29 Second adsorbent transfer device (adsorbent transfer means)
50 Submerged membrane separator (biological treatment means)

Claims

2 or more sets of multi-stage adsorption treatment means comprising two sets of adsorption treatment means for adsorbing ammonium ions in the water to be treated to the adsorbent,
For each multi-stage adsorption treatment means, adsorbent input means for introducing the adsorbent into the water to be treated of the latter-stage adsorption treatment means, and the adsorbent used in the latter-stage adsorption treatment means are transferred to the previous-stage adsorption treatment means. And an adsorbent transfer means.

The water treatment system according to claim 1, further comprising biological treatment means for biologically treating the water to be treated treated by the adsorption treatment means.

The water treatment system according to claim 1 or 2, further comprising an anaerobic treatment means for treating the water to be treated with anaerobic bacteria on the upstream side of the multistage adsorption treatment means.

The water treatment system according to claim 1, wherein the adsorbent is zeolite.