JP3729713B2

JP3729713B2 - Method and apparatus for treating nitrogen-containing organic wastewater

Info

Publication number: JP3729713B2
Application number: JP2000228800A
Authority: JP
Inventors: 富雄鈴木
Original assignee: 株式会社ヒデケン設計
Priority date: 2000-07-28
Filing date: 2000-07-28
Publication date: 2005-12-21
Anticipated expiration: 2020-07-28
Also published as: JP2002035788A

Description

【０００１】
【発明の属する技術分野】
本発明は、窒素含有有機性廃水の処理装置に関し、特に、嫌気性消化槽、脱窒槽、硝化槽、好気性酸化槽を組み合わせたシステムに関する。
【０００２】
【従来の技術】
従来の水処理においては、有機性廃水中の窒素化合物を、廃水処理装置を用いて、酸化し、生成した窒素酸化物を還元して、脱窒処理していた。
【０００３】
例えば、特開平９−８５２７９号公報には、有機性廃水を導入し、嫌気性処理を行う嫌気槽及び脱窒槽と、好気性処理を行う硝化槽と、脱窒槽の処理水に酸素富有ガスを混入させて硝化槽に導入する手段と、硝化槽の処理水の一部を脱窒槽に返送する手段とを設けた酸素曝気式脱窒処理装置が開示されている。
【０００４】
この装置では、十分に嫌気性消化処理を行った有機性廃水を脱窒反応槽に導き、続いて硝化反応槽に導く。硝化反応槽の処理水は、好気性酸化処理槽へ導くが、一部は、前記脱窒反応槽に返送する。また、好気性酸化処理槽からの汚泥を嫌気槽（複数段あるときは嫌気第１槽）に送る。
【０００５】
好気性酸化を行う硝化反応槽では、曝気し、硝化菌の働きによりアンモニア性窒素を硝酸性窒素に硝化させる。硝化反応ずみ処理水の一部を脱窒反応槽に返送し、嫌気性処理により、生成した還元性物質と嫌気性処理で残るＢＯＤ物質とにより、窒素を遊離させる。
【０００６】
しかし、好気性処理はエネルギーを比較的多く必要とし、添加する薬品は高価であり、流入原水のＢＯＤが高い場合には、特に、従来の脱窒ではメタノールのような薬品が必要となることが多かったが、薬品添加は高価であり、また管理も面倒である。
【０００７】
また、特開平１−４４３９７号公報には、嫌気性ろ床を多段に設けた接触消化槽に廃水を流入させて浄化処理し、該処理水を更に接触酸化槽に流入して酸化処理すると共に、該接触酸化槽において生成された汚泥を前記接触消化槽へ返送して、流入廃水の中の有機物質と共に消化分解し、その消化汚泥を槽外に排出させることが開示されている。この方法によると、流入廃水のＢＯＤが２００ｍｇ／ｌの場合、処理水のＢＯＤを１０ｍｇ／ｌ以下にできる。また、流入廃水のＢＯＤが２００ｍｇ／ｌ以上の場合、接触消化槽と接触酸化槽との組み合わせにより、ＢＯＤの除去率を９７％以上にできる。しかし、この発明には脱窒処理については開示していない。
【０００８】
【発明が解決しようとする課題】
本発明は、窒素含有有機性廃水の浮遊物、ＢＯＤ、窒素、及び汚泥の嫌気性消化処理を、効率的に、かつ余計な薬品を必要とせずに行うことのできる生物脱窒処理方法および装置を提供することを目的とする。
【０００９】
【課題を解決するための手段】
本発明の窒素含有有機性廃水の処理装置の第１の態様は、横方向に広がりのある複数の塊または集合体の形の嫌気性接触ろ材が横方向に一定間隔で並べられ、上下に一部が一定間隔で重なり合うように複数段に配設された第１嫌気性接触消化槽と、任意の接触ろ材が充填された第２嫌気性接触消化槽と、脱窒菌を保持した担体を充填した脱窒反応槽と、硝化菌を保持した担体を充填した硝化反応槽と、処理水を排出する手段を備えた好気性酸化処理槽とからなる。担体は、浮遊式あるいは固定式である。
【００１０】
前記第１嫌気性接触消化槽は、窒素含有有機性廃水を導入する手段を備える。
【００１１】
前記第２嫌気性接触消化槽は、第１嫌気性接触消化槽からの処理水を導入する手段を備える。
【００１２】
前記脱窒反応槽は、第２嫌気性接触消化槽からの処理水を導入する手段、および硝化反応槽の処理水の一部を担体と共に、あるいは担体の搬送なしに、導入する手段を備える。
【００１３】
前記硝化反応槽は、脱窒反応槽からの処理水を担体と共に、あるいは担体の搬送なしに、導入する手段および散気装置を備える。
【００１４】
前記好気性酸化処理槽は、硝化反応槽から硝化反応ずみ処理水のみを導入する手段および散気装置を備える。
【００１５】
第１嫌気性接触消化槽には、第２嫌気性接触消化槽および好気性酸化処理槽において発生する浮遊物および汚泥を返送する手段、および嫌気性消化をした余剰汚泥を排出する手段を備える。
【００１６】
本発明の窒素含有有機性廃水の処理方法の第１の態様は、前記処理装置において、窒素含有有機性廃水を第１嫌気性接触消化槽、第２嫌気性接触消化槽に順に導き少なくとも１２時間以上嫌気性消化処理し、処理水を脱窒反応槽および硝化反応槽で反応させ、このとき、硝化反応槽から、硝酸化窒素を含む処理水の一部を担体と共に、あるいは担体の搬送なしに、脱窒反応槽に導入して混合し嫌気性消化で生成した還元性物質と残存するＢＯＤ物質を硝酸と反応させ、脱窒反応させて窒素を遊離ガス化させて排気し、処理水を担体と共に、あるいは担体の搬送なしに、硝化反応槽に導いて、残存するアンモニア性窒素を硝化反応させ、硝化反応槽から硝化反応ずみ処理水のみを好気性酸化処理槽へ導く。
【００１７】
なお、担体はスポンジ状プラスチックの場合、硝化脱窒槽を処理水と共に移動することができるが、セラミック等の担体を固定して処理水のみを移動させることもできる。この場合には、硝化反応槽から好気性処理槽へ処理水のみを移流させるときの担体分離の手段が不要となる。
【００１８】
更に、脱窒反応に対する有機物が不足する場合には、第１嫌気性接触消化槽からの処理水の一部を脱窒反応槽に導入できることが好ましい。さらに、第２嫌気性接触消化槽、硝化反応槽および好気性酸化処理槽において発生する浮遊物および汚泥を第１嫌気性接触消化槽に返送し、第１嫌気性接触消化槽で原水から分離した汚泥と共に十分に嫌気性消化した後、第１嫌気性接触消化槽から余剰汚泥を排出することが好ましい。
【００１９】
本発明の窒素含有有機性廃水の処理装置の第２の態様は、横方向に広がりのある複数の塊または集合体の形の嫌気性接触ろ材が横方向に一定間隔で並べられ、上下に一部が一定間隔で重なり合うように複数段に配設された第１嫌気性接触消化槽と、任意の接触ろ材が充填された第２嫌気性接触消化槽と、脱窒菌を保持した担体を充填した第１脱窒反応槽および第２脱窒反応槽と、硝化菌を保持した担体を充填した第１硝化反応槽および第２硝化反応槽と、処理水を排出する手段を備えた好気性酸化処理槽とからなる。
【００２０】
前記第１嫌気性接触消化槽は、窒素含有有機性廃水を導入する手段を備える。
【００２１】
前記第２嫌気性接触消化槽は、第１嫌気性接触消化槽からの消化反応ずみ処理水を導入する手段を備える。
【００２２】
前記第１脱窒反応槽は、第２嫌気性接触消化槽からの処理水を導入する手段、および第１硝化反応槽の処理水の一部を担体と共に、あるいは担体の搬送なしに、導入する手段を備える。
【００２３】
前記第１硝化反応槽は、第１脱窒反応槽からの処理水を担体と共に、あるいは担体の搬送なしに、導入する手段および散気装置を備える。
【００２４】
前記第２脱窒反応槽は、第１硝化反応槽から硝化反応ずみ処理水のみを導入する手段、および第２硝化反応槽の処理水の一部を担体と共に、あるいは担体の搬送なしに、導入する手段を備える。
【００２５】
前記第２硝化反応槽は、第２脱窒反応槽からの処理水を担体と共に、あるいは担体の搬送なしに、導入する手段および散気装置を備える。
【００２６】
前記好気性酸化処理槽は、第２硝化反応槽から硝化反応ずみ処理水のみを導入する手段および散気装置を備える。
【００２７】
第１嫌気性接触消化槽には、第２嫌気性接触消化槽および好気性酸化処理槽において発生する浮遊物および汚泥を返送する手段を備え、第１嫌気性接触消化槽に余剰汚泥を排出する手段を備える。
【００２８】
本発明の窒素含有有機性廃水の処理方法の第２の態様は、前記処理装置において、窒素含有有機性廃水を第１嫌気性接触消化槽、第２嫌気性接触消化槽に順に導き嫌気性消化処理し、浮遊物質やＢＯＤ物質を処理させると共に、十分な還元性物質を生成させ、処理水を第１脱窒反応槽、第１硝化反応槽、第２脱窒反応槽、第２硝化反応槽で反応させ、このとき、第１硝化反応槽から、硝酸化窒素を含む処理水の一部を担体と共に、あるいは担体の搬送なしに、第１脱窒反応槽に導入して混合し、脱窒反応させて窒素を遊離ガス化させて排気し、処理水を担体と共に、あるいは担体の搬送なしに、第１硝化反応槽に導いて、残存するアンモニア性窒素を硝化反応させ、第１硝化反応槽から硝化反応ずみ処理水のみを第２脱窒反応槽に導き、第２硝化反応槽から、硝酸化窒素を含む処理水の一部を担体と共に、あるいは担体の搬送なしに、第２脱窒反応槽に導入して混合し、脱窒反応させて窒素を遊離ガス化させて排気し、処理水を担体と共に、あるいは担体の搬送なしに、第２硝化反応槽に導いて、残存するアンモニア性窒素を硝化反応させ、第２硝化反応槽から硝化反応ずみ処理水のみを好気性酸化処理槽へ導く。
【００２９】
更に、脱窒反応に対する有機物が不足する場合には、第１嫌気性接触消化槽からの処理水の一部を第１脱窒反応槽および第２脱窒反応槽に導入できることが好ましい。さらに、第２嫌気性接触消化槽、第１硝化反応槽、第２硝化反応槽および好気性酸化処理槽において発生する浮遊物および汚泥を第１嫌気性接触消化槽に返送し、第１嫌気性接触消化槽で原水から分離した汚泥と共に十分に嫌気性消化した後、第１嫌気性接触消化槽から余剰汚泥を排出することが好ましい。脱窒をより徹底して行う場合には、第２脱窒反応槽に窒素分を含まないメタノール等のＢＯＤ物質を添加することができる。
【００３０】
【発明の実施の形態】
図１のシステム図に基づいて、本発明の一実施例を説明する。
【００３１】
本発明の生物脱窒処理装置は、横方向に広がりのある複数の塊または集合体の形の嫌気性接触ろ材が横方向に一定間隔で並べられ、上下に一部が一定間隔で重なり合うように複数段に配設された第１嫌気性接触消化槽１０と、任意の接触ろ材が充填された第２嫌気性接触消化槽２０と、脱窒菌を保持した担体を充填した脱窒反応槽３０と、硝化菌を保持する担体を充填した硝化反応槽４０と、処理水を排出する手段を備えた好気性酸化処理槽５０とからなる。
【００３２】
前記第１嫌気性接触消化槽１０は、窒素含有有機性廃水１を導入する手段を備える。
【００３３】
前記第２嫌気性接触消化槽２０は、第１嫌気性接触消化槽１０からの処理水１３を導入する手段を備える。
【００３４】
前記脱窒反応槽３０は、第２嫌気性接触消化槽２０からの処理水２１を導入する手段、および硝化反応槽４０の処理水の一部４２を担体と共に、あるいは担体の搬送なしに、導入する手段を備える。
【００３５】
前記硝化反応槽４０は、脱窒反応槽３０からの処理水３１を担体と共に、あるいは担体の搬送なしに、導入する手段および散気装置６１を備える。
【００３６】
前記好気性酸化処理槽５０は、硝化反応槽４０から硝化反応ずみ処理水４３のみを導入する手段および散気装置６２を備える。
【００３７】
第１嫌気性接触消化槽１０には、第２嫌気性接触消化槽２０において発生する汚泥２４を返送する手段、および好気性酸化処理槽５０において発生する汚泥５４を返送する手段を備え、余剰汚泥１５を排出する手段を備える。
【００３８】
窒素含有有機性廃水の嫌気性処理は、第１嫌気性接触消化槽および第２嫌気性接触消化槽の２段階で行う。
【００３９】
第１嫌気性接触消化槽および第２嫌気性接触消化槽に充填される接触ろ材は浮遊性または固定性など任意でよく、例えば特公平１−４４３９７号に開示される接触ろ床を利用できる。
【００４０】
脱窒反応槽３０および硝化反応槽４０に充填する担体には、脱窒菌を保持させる。該担体としては、本実施例では１０ｍｍの立方体のスポンジ状プラスチックの浮遊式担体を使用した。しかし、比重の大きいセラミック製の固定式担体を使用してもよい。
【００４１】
また、本実施例では、硝化反応槽４０と脱窒反応槽３０との１回で処理水を担体と共に循環させている。しかし、循環させない場合は、処理水の流出口にスクリーンを設けて、処理水のみを流出させればよい。
【００４２】
次に、本発明の装置の動作を説明する。
【００４３】
２段階の嫌気性接触消化槽１０、２０により、例えば、ＢＯＤ２００ｍｇ／ｌ程度の流入原水を、第１嫌気性接触消化槽１０で、ＢＯＤ１００ｍｇ／ｌ程度に処理し、この処理水をさらに第２嫌気性接触消化槽２０で、ＢＯＤ３０〜７０ｍｇ／ｌに処理することができる。この水質にするためには、第１および第２嫌気性接触消化槽で少なくとも１２時間以上の嫌気性反応が必要である。
【００４４】
第２嫌気性接触消化槽２０における嫌気性反応によって、酸化還元電位が−３００ｍＶ以下で、ＢＯＤは３０〜７０ｍｇ／ｌとなる。
【００４５】
第２嫌気性接触消化槽２０の処理水２１を、脱窒反応槽３０に導き、続いて硝化反応槽４０に導く。硝化反応槽４０からの硝化反応ずみ処理水４３は、好気性酸化処理槽５０へ導くが、処理水の一部４２は、担体と共に、あるいは担体の搬送なしに、前記脱窒反応槽３０に返送する。
【００４６】
好気性酸化を行う硝化反応槽４０では、散気装置６１により空気で曝気し、硝化菌の働きによりアンモニア性窒素を硝酸性窒素に硝化させる。
【００４７】
硝化反応槽４０で硝化した処理水の一部４３は、スクリーンを介して、担体を分離し好気性処理槽５０へ、また、脱窒反応槽３０へ担体と共に、あるいは担体の搬送なしに、処理水４２が返送され、第２嫌気性接触消化槽２０の処理水２１と混合され、脱窒が効果的に行われる。すなわち、硝化反応槽４０の処理水の一部４２を返送した脱窒反応槽３０では、嫌気性処理により生成した還元性物質と残存するＢＯＤ物質により、硝酸性窒素の結合酸素を奪い、窒素を遊離させる。脱窒された処理水３１は、再び硝化反応槽４０に戻り、残存するアンモニアを硝化する。
【００４８】
このように、ＢＯＤ物質と硝酸性窒素とを反応させるが、本発明の脱窒反応槽３０では、嫌気性反応が十分に進み、還元性物質が生成し、なおかつ、適度なＢＯＤ物質が残留している第２嫌気性接触消化槽２０からの処理水２１と、硝化反応槽４０で硝酸化した硝酸性窒素とを反応させることにより、添加物質を使用しないで、脱窒を効果的に行うことができる。
【００４９】
上記のように、硝化反応槽４０での嫌気性処理の後において、還元性物質およびＢＯＤ物質が、脱窒反応に必要な量であればよい。しかし、硝化反応槽４０内の還元性物質およびＢＯＤ物質が、脱窒反応に十分でない場合には、例えばメタノールのような薬品６０を混入することが行える。あるいは、処理の途中で、すなわち嫌気性処理が十分に進んでいない第１嫌気性接触消化槽１０から処理水を分水１２して、脱窒反応槽３０に導入し、必要な水素供与体を補給するとよい。このようにすると、例えばメタノール等の薬品のような添加物を必要としないで、脱窒を行うことができる。なお、薬品注入や嫌気性処理水の分水注入は、弁７０により切り替えられる。
【００５０】
第２嫌気性接触消化槽２０において発生する汚泥２４、および好気性酸化処理槽５０において発生する汚泥５４は、第１嫌気性接触消化槽１０に返送し、流入原水１から分離した汚泥とともに、十分に嫌気性処理した後、余剰汚泥１５として搬出処分する。
【００５１】
図２のシステム図に基づいて、本発明の異なる一実施例を説明する。
【００５２】
前実施例と異なるのは、脱窒反応槽および消化反応槽が２組ある。
【００５３】
第１脱窒反応槽３０は、第２嫌気性接触消化槽２０からの処理水２１を導入する手段、第１嫌気性接触消化槽１０からの処理水の一部１２を導入する手段、および第１硝化反応槽４０の処理水の一部４２を導入する手段を備える。
【００５４】
前記第１硝化反応槽４０は、第１脱窒反応槽３０からの処理水３１を導入する手段および散気装置６１を備える。
【００５５】
前記第２脱窒反応槽３５は、前記第１硝化反応槽４０から硝化反応ずみ処理水４３を導入する手段、第１嫌気性接触消化槽１０からの処理水の一部１２を導入する手段、および第２硝化反応槽４５の処理水の一部４７を導入する手段、メタノール等の薬品を注入する手段を備える。また、薬品注入のときに、嫌気性処理水の注入を止める弁７０を設けてある。
【００５６】
前記第２硝化反応槽４５は、第２脱窒反応槽３５からの処理水３６を導入する手段および散気装置６２を備える。
【００５７】
その他の構成は、前述した実施例と同じである。
【００５８】
【実施例】
図１に示す構成により、１日５００リットルの処理能力の実験装置で、有機性廃水として、ＢＯＤ２００ｍｇ／ｌ、全窒素量３５ｍｇ／ｌの都市下水を処理した結果、ＢＯＤ１１ｍｇ／ｌ、全窒素量８．５ｍｇ／ｌの処理水が得られた。
【００５９】
また、図２に示す構成により、１日５００リットルの処理能力の実験装置で、有機性廃水として、ＢＯＤ２００ｍｇ／ｌ、全窒素量３５ｍｇ／ｌの都市下水を処理した結果、ＢＯＤ８ｍｇ／ｌ、全窒素量５．５ｍｇ／ｌの処理水が得られた。
【００６０】
【発明の効果】
以上、詳述したように、本発明では、窒素含有有機性廃水の浮遊物、ＢＯＤ、窒素、及び汚泥の嫌気性消化処理を、効率的に、かつ余計な薬品を必要とせずに、行うことができる。
【図面の簡単な説明】
【図１】本発明の一実施例を示すシステム図である。
【図２】本発明の異なる一実施例を示すシステム図である。
【符号の説明】
１有機性廃水
１０第１嫌気性脱窒消化槽
１２、１３、２１、３１、３６、４２、４７、５１処理水
１５余剰汚泥
２０第２嫌気性脱窒消化槽
２４、５４汚泥
３０、３５脱窒反応槽
４０、４５硝化反応槽
４３、４８上澄み水
５０好気性酸化処理槽
６０薬品
６１、６２、６３散気装置
７０弁[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a treatment apparatus for nitrogen-containing organic wastewater, and more particularly to a system combining an anaerobic digestion tank, a denitrification tank, a nitrification tank, and an aerobic oxidation tank.
[0002]
[Prior art]
In conventional water treatment, nitrogen compounds in organic wastewater are oxidized using a wastewater treatment apparatus, and the generated nitrogen oxides are reduced to perform denitrification treatment.
[0003]
For example, in JP-A-9-85279, an organic waste water is introduced, an anaerobic tank and a denitrification tank for anaerobic treatment, a nitrification tank for an aerobic treatment, and an oxygen-rich gas in the treated water of the denitrification tank. An oxygen-aeration type denitrification treatment apparatus provided with means for mixing and introducing into a nitrification tank and means for returning part of the treated water in the nitrification tank to the denitrification tank is disclosed.
[0004]
In this apparatus, organic waste water that has been subjected to a sufficient anaerobic digestion treatment is guided to a denitrification reaction tank, and subsequently to a nitrification reaction tank. The treated water in the nitrification reaction tank is led to the aerobic oxidation treatment tank, but a part is returned to the denitrification reaction tank. Also, the sludge from the aerobic oxidation treatment tank is sent to the anaerobic tank (anaerobic first tank when there are multiple stages).
[0005]
In a nitrification reaction tank that performs aerobic oxidation, aeration is performed and ammonia nitrogen is nitrified to nitrate nitrogen by the action of nitrifying bacteria. A part of the nitrification-reacted treated water is returned to the denitrification reaction tank, and nitrogen is liberated by the generated reducing substance and the BOD substance remaining after the anaerobic treatment by anaerobic treatment.
[0006]
However, the aerobic treatment requires a relatively large amount of energy, the chemicals to be added are expensive, and especially when the BOD of the inflowing raw water is high, chemicals such as methanol may be required particularly in conventional denitrification. However, the addition of chemicals is expensive and cumbersome to manage.
[0007]
Japanese Patent Laid-Open No. 1-44397 discloses that waste water is introduced into a contact digestion tank provided with anaerobic filter beds in multiple stages for purification, and the treated water is further introduced into a contact oxidation tank for oxidation treatment. It is disclosed that sludge generated in the contact oxidation tank is returned to the contact digestion tank, digested and decomposed together with organic substances in the inflow wastewater, and the digested sludge is discharged out of the tank. According to this method, when the BOD of the influent wastewater is 200 mg / l, the BOD of the treated water can be 10 mg / l or less. Moreover, when the BOD of inflow waste water is 200 mg / l or more, the removal rate of BOD can be 97% or more by the combination of the contact digestion tank and the contact oxidation tank. However, this invention does not disclose denitrification treatment.
[0008]
[Problems to be solved by the invention]
The present invention relates to a biological denitrification method and apparatus capable of performing anaerobic digestion of suspended matter, BOD, nitrogen, and sludge of nitrogen-containing organic wastewater efficiently and without the need for extra chemicals. The purpose is to provide.
[0009]
[Means for Solving the Problems]
The first aspect of the nitrogen-containing organic wastewater treatment apparatus of the present invention is that anaerobic contact filter media in the form of a plurality of lumps or aggregates extending in the lateral direction are arranged at regular intervals in the lateral direction, and are vertically aligned. The first anaerobic contact digester disposed in a plurality of stages so that the portions overlap at regular intervals, the second anaerobic contact digester filled with an arbitrary contact filter medium, and a carrier holding denitrifying bacteria were filled. It consists of a denitrification reaction tank, a nitrification reaction tank filled with a carrier holding nitrifying bacteria, and an aerobic oxidation treatment tank equipped with means for discharging treated water. The carrier is a floating type or a fixed type.
[0010]
The first anaerobic contact digester comprises means for introducing nitrogen-containing organic wastewater.
[0011]
The second anaerobic contact digester is provided with means for introducing treated water from the first anaerobic contact digester.
[0012]
The denitrification reaction tank includes means for introducing treated water from the second anaerobic catalytic digestion tank, and means for introducing a part of the treated water of the nitrification reaction tank together with the carrier or without transporting the carrier.
[0013]
The nitrification reaction tank comprises means for introducing treated water from the denitrification reaction tank together with the carrier or without carrying the carrier and a diffuser.
[0014]
The aerobic oxidation treatment tank includes means for introducing only nitrification reaction-treated water from the nitrification reaction tank and an air diffuser.
[0015]
The first anaerobic contact digester is equipped with means for returning suspended matter and sludge generated in the second anaerobic contact digester and the aerobic oxidation treatment tank, and means for discharging excess sludge after anaerobic digestion.
[0016]
According to a first aspect of the method for treating nitrogen-containing organic wastewater of the present invention, in the treatment apparatus, the nitrogen-containing organic wastewater is sequentially introduced into the first anaerobic contact digester and the second anaerobic contact digester for at least 12 hours. As described above, the anaerobic digestion treatment is performed, and the treated water is reacted in the denitrification reaction tank and the nitrification reaction tank. At this time, a part of the treated water containing nitrogen nitrate is transferred from the nitrification reaction tank together with the carrier or without carrying the carrier. The reductive substance produced by anaerobic digestion and mixed into the denitrification reactor and reacted with the remaining BOD substance are reacted with nitric acid, denitrified and nitrogen is released into a free gas and exhausted, and the treated water is supported by the carrier. At the same time, or without transporting the carrier, it is guided to the nitrification reaction tank to cause the remaining ammoniacal nitrogen to undergo a nitrification reaction, and only the nitrification reaction-treated water is guided from the nitrification reaction tank to the aerobic oxidation treatment tank.
[0017]
In the case where the carrier is sponge-like plastic, the nitrification denitrification tank can be moved together with the treated water, but only the treated water can be moved by fixing a carrier such as ceramic. In this case, there is no need for means for separating the carrier when only the treated water is transferred from the nitrification reaction tank to the aerobic treatment tank.
[0018]
Furthermore, when there is a shortage of organic matter for the denitrification reaction, it is preferable that a part of the treated water from the first anaerobic contact digestion tank can be introduced into the denitrification reaction tank. Furthermore, the suspended matter and sludge generated in the second anaerobic contact digester, nitrification reactor and aerobic oxidation tank are returned to the first anaerobic contact digester and separated from the raw water in the first anaerobic contact digester. After sufficient anaerobic digestion with sludge, it is preferable to discharge excess sludge from the first anaerobic contact digester.
[0019]
The second aspect of the nitrogen-containing organic wastewater treatment apparatus of the present invention is that anaerobic contact filter media in the form of a plurality of lumps or aggregates extending in the lateral direction are arranged at regular intervals in the lateral direction, and are vertically aligned. The first anaerobic contact digester disposed in a plurality of stages so that the portions overlap at regular intervals, the second anaerobic contact digester filled with an arbitrary contact filter medium, and a carrier holding denitrifying bacteria were filled. An aerobic oxidation treatment comprising a first denitrification reaction tank and a second denitrification reaction tank, a first nitrification reaction tank and a second nitrification reaction tank filled with a carrier holding nitrifying bacteria, and means for discharging treated water It consists of a tank.
[0020]
The first anaerobic contact digester comprises means for introducing nitrogen-containing organic wastewater.
[0021]
The second anaerobic contact digester is provided with means for introducing digested reaction-treated water from the first anaerobic contact digester.
[0022]
The first denitrification reaction tank introduces means for introducing treated water from the second anaerobic catalytic digestion tank, and part of the treated water of the first nitrification reaction tank together with the carrier or without carrying the carrier. Means.
[0023]
The first nitrification reaction tank includes a means for introducing the treated water from the first denitrification reaction tank together with the carrier or without conveying the carrier and an air diffuser.
[0024]
The second denitrification reaction tank is a means for introducing only nitrification reaction-treated water from the first nitrification reaction tank, and a part of the treatment water of the second nitrification reaction tank is introduced together with the carrier or without carrying the carrier. Means are provided.
[0025]
The second nitrification reaction tank includes means for introducing treated water from the second denitrification reaction tank together with the carrier or without carrying the carrier and an air diffuser.
[0026]
The aerobic oxidation treatment tank includes means for introducing only nitrification reaction-treated water from the second nitrification reaction tank and an aeration device.
[0027]
The first anaerobic contact digester is equipped with means for returning suspended matter and sludge generated in the second anaerobic contact digester and the aerobic oxidation tank, and the excess sludge is discharged to the first anaerobic contact digester. Means.
[0028]
According to a second aspect of the method for treating nitrogen-containing organic wastewater of the present invention, in the treatment apparatus, the nitrogen-containing organic wastewater is sequentially guided to the first anaerobic contact digester and the second anaerobic contact digester. Treats and processes suspended substances and BOD substances, generates sufficient reducing substances, and treats treated water into first denitrification reaction tank, first nitrification reaction tank, second denitrification reaction tank, and second nitrification reaction tank. At this time, a part of the treated water containing nitrogen nitrate is introduced into the first denitrification reaction tank from the first nitrification reaction tank together with the carrier or without carrying the carrier, and mixed, and then denitrified. Nitrogen is converted into free gas by the reaction and exhausted, and the treated water is guided to the first nitrification reaction tank with or without the carrier, and the remaining ammoniacal nitrogen is nitrified and the first nitrification reaction tank From the nitrification reaction-treated water only to the second denitrification reactor, From the nitrification reaction tank, a part of the treated water containing nitrogen nitrate is introduced into the second denitrification reaction tank with or without transport of the support and mixed, and denitrification is performed to convert nitrogen into a free gas. Then, the treated water is introduced into the second nitrification reaction tank together with the carrier or without transporting the carrier, and the remaining ammoniacal nitrogen is subjected to nitrification reaction. From the second nitrification reaction tank, only the nitrification reaction-treated water is preferred. Lead to the aerobic oxidation tank.
[0029]
Furthermore, when the organic matter for the denitrification reaction is insufficient, it is preferable that a part of the treated water from the first anaerobic contact digestion tank can be introduced into the first denitrification reaction tank and the second denitrification reaction tank. Furthermore, the suspended matter and sludge generated in the second anaerobic contact digestion tank, the first nitrification reaction tank, the second nitrification reaction tank and the aerobic oxidation treatment tank are returned to the first anaerobic contact digestion tank, and the first anaerobic contact is obtained. After sufficient anaerobic digestion with the sludge separated from the raw water in the contact digester, it is preferable to discharge excess sludge from the first anaerobic contact digester. When denitrification is performed more thoroughly, a BOD substance such as methanol that does not contain nitrogen can be added to the second denitrification reaction tank.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described based on the system diagram of FIG.
[0031]
In the biological denitrification apparatus of the present invention, anaerobic contact filter media in the form of a plurality of lumps or aggregates extending in the lateral direction are arranged at regular intervals in the lateral direction, and a part thereof is overlapped vertically. A first anaerobic contact digestion tank 10 arranged in a plurality of stages, a second anaerobic contact digestion tank 20 filled with an arbitrary contact filter medium, and a denitrification reaction tank 30 filled with a carrier holding denitrifying bacteria. The nitrification reaction tank 40 is filled with a carrier that holds nitrifying bacteria, and the aerobic oxidation treatment tank 50 is provided with means for discharging treated water.
[0032]
The first anaerobic contact digester 10 includes means for introducing the nitrogen-containing organic waste water 1.
[0033]
The second anaerobic contact digester 20 includes means for introducing the treated water 13 from the first anaerobic contact digester 10.
[0034]
The denitrification reaction tank 30 introduces means for introducing the treated water 21 from the second anaerobic catalytic digestion tank 20 and a part of the treated water 42 of the nitrification reaction tank 40 together with the carrier or without transporting the carrier. Means are provided.
[0035]
The nitrification reaction tank 40 includes means for introducing the treated water 31 from the denitrification reaction tank 30 together with the carrier or without carrying the carrier and an air diffuser 61.
[0036]
The aerobic oxidation treatment tank 50 includes means for introducing only the nitrification reaction-treated water 43 from the nitrification reaction tank 40 and an air diffuser 62.
[0037]
The first anaerobic contact digestion tank 10 includes means for returning the sludge 24 generated in the second anaerobic contact digestion tank 20 and means for returning the sludge 54 generated in the aerobic oxidation treatment tank 50, and excess sludge. 15 is provided.
[0038]
The anaerobic treatment of nitrogen-containing organic wastewater is performed in two stages, a first anaerobic contact digester and a second anaerobic contact digester.
[0039]
The contact filter medium filled in the first anaerobic contact digester and the second anaerobic contact digester may be arbitrary, such as floating or fixed, and for example, a contact filter bed disclosed in Japanese Patent Publication No. 1-444397 can be used.
[0040]
The carrier filled in the denitrification reaction tank 30 and the nitrification reaction tank 40 holds denitrification bacteria. In this example, a 10 mm cubic sponge-like plastic floating carrier was used as the carrier. However, a ceramic fixed carrier having a large specific gravity may be used.
[0041]
In this embodiment, the treated water is circulated together with the carrier in one time in the nitrification reaction tank 40 and the denitrification reaction tank 30. However, when not circulating, it is only necessary to provide a screen at the outlet of the treated water so that only the treated water flows out.
[0042]
Next, the operation of the apparatus of the present invention will be described.
[0043]
For example, inflow raw water of about 200 mg / l BOD is treated to about 100 mg / l BOD in the first anaerobic contact digestion tank 10 by the two-stage anaerobic contact digestion tanks 10, 20. In the sexual contact digester 20, the BOD can be processed to 30 to 70 mg / l. In order to achieve this water quality, an anaerobic reaction of at least 12 hours or more is required in the first and second anaerobic contact digesters.
[0044]
Due to the anaerobic reaction in the second anaerobic contact digester 20, the redox potential is −300 mV or less and the BOD is 30 to 70 mg / l.
[0045]
The treated water 21 of the second anaerobic contact digestion tank 20 is guided to the denitrification reaction tank 30 and then to the nitrification reaction tank 40. The nitrification-reacted treated water 43 from the nitrification reaction tank 40 is led to the aerobic oxidation treatment tank 50, but a part of the treated water 42 is returned to the denitrification reaction tank 30 together with the carrier or without transporting the carrier. To do.
[0046]
In the nitrification reaction tank 40 that performs aerobic oxidation, aeration apparatus 61 aerates with air and nitrifies ammoniacal nitrogen to nitrate nitrogen by the action of nitrifying bacteria.
[0047]
A part 43 of the treated water nitrified in the nitrification reaction tank 40 is separated through a screen and separated into the aerobic treatment tank 50, to the denitrification reaction tank 30, with the carrier, or without carrying the carrier. The water 42 is returned and mixed with the treated water 21 of the second anaerobic contact digestion tank 20 to effectively perform denitrification. That is, in the denitrification reaction tank 30 that has returned part of the treated water 42 in the nitrification reaction tank 40, the reducing oxygen produced by the anaerobic treatment and the remaining BOD substance deprive the bound oxygen of the nitrate nitrogen and remove the nitrogen. Release. The denitrified treated water 31 is returned to the nitrification reaction tank 40 again to nitrify the remaining ammonia.
[0048]
As described above, the BOD substance and nitrate nitrogen are reacted. In the denitrification reaction tank 30 of the present invention, the anaerobic reaction proceeds sufficiently, a reducing substance is generated, and an appropriate BOD substance remains. The denitrification can be effectively performed without using any additional substances by reacting the treated water 21 from the second anaerobic contact digestion tank 20 with nitrate nitrogen nitrated in the nitrification reaction tank 40. Can do.
[0049]
As described above, after the anaerobic treatment in the nitrification reaction tank 40, the reducing substance and the BOD substance may be in amounts necessary for the denitrification reaction. However, when the reducing substance and the BOD substance in the nitrification reaction tank 40 are not sufficient for the denitrification reaction, for example, a chemical 60 such as methanol can be mixed. Alternatively, in the middle of the treatment, that is, the treated water from the first anaerobic catalytic digestion tank 10 in which the anaerobic treatment is not sufficiently progressed 12 is introduced into the denitrification reaction tank 30, and the necessary hydrogen donor is supplied. Replenish. In this way, denitrification can be performed without requiring an additive such as a chemical such as methanol. The injection of chemicals and the split water injection of anaerobic treated water are switched by a valve 70.
[0050]
The sludge 24 generated in the second anaerobic contact digestion tank 20 and the sludge 54 generated in the aerobic oxidation treatment tank 50 are returned to the first anaerobic contact digestion tank 10 together with the sludge separated from the inflow raw water 1 After anaerobic treatment, the excess sludge 15 is taken out and disposed of.
[0051]
A different embodiment of the present invention will be described based on the system diagram of FIG.
[0052]
The difference from the previous example is that there are two sets of denitrification reaction tank and digestion reaction tank.
[0053]
The first denitrification reaction tank 30 is a means for introducing treated water 21 from the second anaerobic contact digestion tank 20, a means for introducing a part 12 of treated water from the first anaerobic contact digestion tank 10, and a first 1 is provided with a means for introducing a part 42 of treated water in the nitrification reaction tank 40.
[0054]
The first nitrification reaction tank 40 includes means for introducing treated water 31 from the first denitrification reaction tank 30 and an air diffuser 61.
[0055]
The second denitrification reaction tank 35 is a means for introducing the nitrification-reacted treated water 43 from the first nitrification reaction tank 40, a means for introducing a part 12 of the treated water from the first anaerobic contact digestion tank 10, And means for introducing a part 47 of treated water in the second nitrification reaction tank 45 and means for injecting chemicals such as methanol. Further, a valve 70 is provided to stop the anaerobic treated water injection when the chemical is injected.
[0056]
The second nitrification reaction tank 45 includes means for introducing the treated water 36 from the second denitrification reaction tank 35 and an air diffuser 62.
[0057]
Other configurations are the same as those of the above-described embodiment.
[0058]
【Example】
With the configuration shown in FIG. 1, as a result of treating municipal wastewater having a BOD of 200 mg / l and a total nitrogen amount of 35 mg / l as an organic wastewater with an experimental apparatus having a processing capacity of 500 liters per day, a BOD of 11 mg / l and a total nitrogen amount of 8 Processed water of 5 mg / l was obtained.
[0059]
In addition, as a result of treating municipal wastewater with BOD 200 mg / l and total nitrogen amount 35 mg / l as organic wastewater with an experimental apparatus having a processing capacity of 500 liters per day, the configuration shown in FIG. 2 resulted in BOD 8 mg / l, total nitrogen A treated water amount of 5.5 mg / l was obtained.
[0060]
【The invention's effect】
As described above in detail, in the present invention, the anaerobic digestion treatment of suspended matter, BOD, nitrogen, and sludge of nitrogen-containing organic wastewater is performed efficiently and without requiring extra chemicals. Can do.
[Brief description of the drawings]
FIG. 1 is a system diagram showing an embodiment of the present invention.
FIG. 2 is a system diagram showing a different embodiment of the present invention.
[Explanation of symbols]
1 Organic waste water 10 First anaerobic denitrification digester 12, 13, 21, 31, 36, 42, 47, 51 Treated water 15 Excess sludge 20 Second anaerobic denitrification digester 24, 54 Sludge 30, 35 Nitrogen reaction tank 40, 45 Nitrification reaction tank 43, 48 Supernatant water 50 Aerobic oxidation treatment tank 60 Chemicals 61, 62, 63 Air diffuser 70 Valve

Claims

A first anaerobic arrangement in which anaerobic contact filter media in the form of a plurality of lumps or aggregates extending in the lateral direction are arranged at regular intervals in the lateral direction, and are arranged in a plurality of stages so as to partially overlap each other vertically , A second anaerobic contact digester filled with an optional contact filter medium, a denitrification reactor filled with a carrier holding denitrifying bacteria, and a nitrification reactor filled with a carrier holding nitrifying bacteria And an aerobic oxidation treatment tank equipped with means for discharging treated water, wherein the first anaerobic contact digestion tank comprises means for introducing nitrogen-containing organic waste water, and the second anaerobic contact digestion tank. Comprises means for introducing treated water from the first anaerobic contact digestion tank, the denitrification reaction tank comprises means for introducing treated water from the second anaerobic contact digestion tank, and treated water of the nitrification reaction tank A means for introducing a part of the carrier together with the carrier or without carrying the carrier. The nitrification reaction tank comprises means for introducing treated water from the denitrification reaction tank together with the carrier or without transport of the carrier and a diffuser, and the aerobic oxidation treatment tank is nitrified from the nitrification reaction tank. Means for introducing only the treated water and a diffuser, and means for returning suspended matter and sludge generated in the second anaerobic contact digester and aerobic oxidation tank to the first anaerobic contact digester And a means for discharging excess sludge in the first anaerobic contact digestion tank.

The nitrogen-containing organic wastewater treatment apparatus according to claim 1 leads the nitrogen-containing organic wastewater to the first anaerobic contact digestion tank and the second anaerobic contact digestion tank in order, and performs anaerobic digestion treatment to remove the treated water. In the method of reacting in a nitrification reaction tank, a nitrification reaction tank, and an aerobic oxidation treatment tank, a part of the treated water containing nitrogen nitrate from the nitrification reaction tank is transferred to the denitrification reaction tank together with the carrier or without carrying the carrier. Introduce, mix, denitrify, convert nitrogen into free gas, exhaust, treat the treated water with or without carrier, and lead to nitrification reaction tank to nitrify the remaining ammonia nitrogen. Then, only the nitrification reaction treated water is led from the nitrification reaction tank to the aerobic oxidation treatment tank, and the suspended matter and sludge generated in the second anaerobic contact digestion tank and aerobic oxidation treatment tank are returned to the first anaerobic contact digestion tank And anaerobic digestion to produce excess sludge Method of treating nitrogen-containing organic waste water, characterized in that the discharge.

A first anaerobic arrangement in which anaerobic contact filter media in the form of a plurality of lumps or aggregates extending in the lateral direction are arranged at regular intervals in the lateral direction, and are arranged in a plurality of stages so as to partially overlap each other vertically A second anaerobic contact digestion tank filled with an optional contact filter medium, a first denitrification reaction tank and a second denitrification reaction tank filled with a carrier holding denitrifying bacteria, and nitrifying bacteria The first nitrification reaction tank and the second nitrification reaction tank filled with the held carrier, and an aerobic oxidation treatment tank equipped with means for discharging treated water, wherein the first anaerobic contact digestion tank comprises a nitrogen-containing organic The second anaerobic contact digester is equipped with means for introducing treated water from the first anaerobic contact digester, and the first denitrification reactor is second anaerobic. Means for introducing treated water from the contact digestion tank, and part of the treated water in the first nitrification reaction tank The first nitrification reaction tank is provided with means for introducing the carrier with or without transporting the carrier, and the first nitrification reaction tank is equipped with means for introducing the treated water from the first denitrification reaction tank with or without the carrier. The second denitrification reaction tank includes means for introducing only nitrification reaction-treated water from the first nitrification reaction tank, and a part of the treatment water of the second nitrification reaction tank together with the carrier, The second nitrification reaction tank is provided with means for introducing the treated water from the second denitrification reaction tank together with the carrier or without carrying the carrier, and an air diffuser. The aerobic oxidation treatment tank includes means for introducing only nitrification-reacted treated water from the second nitrification reaction tank and an air diffuser, and the first anaerobic contact digestion tank includes the second anaerobic contact digestion tank and the aerobic reaction tank. Suspended matter generated in the oxidation treatment tank And comprising means for returning the sludge processing apparatus of the nitrogen-containing organic wastewater characterized in that it comprises a means for discharging the excess sludge in the first anaerobic contact digesters.

By the nitrogen-containing organic wastewater treatment apparatus according to claim 3, the nitrogen-containing organic wastewater is sequentially introduced into the first anaerobic contact digester and the second anaerobic contact digester and subjected to anaerobic digestion. 1 denitrification reaction tank, first nitrification reaction tank, second denitrification reaction tank, second nitrification reaction tank, aerobic oxidation treatment tank, in the method of reacting, from the first nitrification reaction tank, treated water containing nitrate nitrate A part of the sample is introduced into the first denitrification reaction tank together with the carrier or without carrying the carrier, mixed, denitrogenated to convert nitrogen into a free gas and exhausted, and treated water with the carrier or with the carrier. Without transporting, the remaining ammonia nitrogen is introduced into the first nitrification reaction tank, and the remaining nitrification reaction water is led from the first nitrification reaction tank to the second denitrification reaction tank. Part of the treated water containing nitrogen nitrate from the tank along with the carrier Without transporting the sample, it is introduced into the second denitrification reaction tank, mixed, denitrified and nitrogen is converted into a free gas and exhausted, and the treated water is transported with the carrier or without transporting the carrier. Lead to the tank, let the remaining ammonia nitrogen react with nitrification, and lead only the nitrification-reacted treated water from the second nitrification reaction tank to the aerobic oxidation treatment tank. In the second anaerobic contact digestion tank and aerobic oxidation treatment tank A method for treating nitrogen-containing organic wastewater, wherein the generated suspended matter and sludge are returned to the first anaerobic contact digester, and subjected to anaerobic digestion and discharged as excess sludge.