JP2003024982A - Biological denitrification method and biological denitrification apparatus - Google Patents
Biological denitrification method and biological denitrification apparatusInfo
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- JP2003024982A JP2003024982A JP2001216950A JP2001216950A JP2003024982A JP 2003024982 A JP2003024982 A JP 2003024982A JP 2001216950 A JP2001216950 A JP 2001216950A JP 2001216950 A JP2001216950 A JP 2001216950A JP 2003024982 A JP2003024982 A JP 2003024982A
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- denitrification
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、アンモニア性窒素
を含有する原水を、アンモニア性窒素を電子供与体と
し、亜硝酸性窒素を電子受容体とする脱窒微生物の作用
で亜硝酸性窒素の存在下に生物脱窒する生物脱窒方法及
び生物脱窒装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses raw water containing ammoniacal nitrogen as a source of denitrifying microorganisms by using ammoniacal nitrogen as an electron donor and nitrite nitrogen as an electron acceptor. TECHNICAL FIELD The present invention relates to a biological denitrification method and a biological denitrification apparatus for performing biological denitrification in the presence.
【０００２】[0002]
【従来の技術】従来、水中の窒素除去方法として、硝化
細菌によりアンモニア性窒素を亜硝酸性窒素や硝酸性窒
素に酸化し、次にメタノール等の電子供与体を添加しつ
つ脱窒細菌により亜硝酸性窒素や硝酸性窒素を窒素ガス
に還元して、水中から窒素を除去する方法が知られてい
る。2. Description of the Related Art Conventionally, as a method for removing nitrogen in water, nitrifying bacteria oxidize ammoniacal nitrogen to nitrite nitrogen or nitrate nitrogen, and then denitrifying bacteria by adding an electron donor such as methanol. A method is known in which nitrate nitrogen or nitrate nitrogen is reduced to nitrogen gas to remove nitrogen from water.
【０００３】この方法はアンモニア性窒素を窒素ガスに
酸化するために必要な酸化力よりも過剰の酸素を必要と
するため、酸素を多く必要とし、この酸素を微生物に供
給するためのエネルギーコストが高くつく。また、脱窒
反応のために電子供与体としてメタノール等の有機物を
添加するためのコストがかかり、またこの有機物を摂取
して増殖した脱窒細菌が余剰汚泥となるため、廃棄物の
処分コストも高くつくという問題がある。特に、硝酸性
窒素は亜硝酸性窒素に比べてより酸化された状態にある
ため、このための酸素供給コストも高く、また、これを
還元するための電子供与体もより多く必要であり、発生
する余剰汚泥量も多い。This method requires more oxygen than the oxidizing power required to oxidize ammoniacal nitrogen to nitrogen gas, and thus requires a large amount of oxygen, and the energy cost for supplying this oxygen to microorganisms is high. Expensive. In addition, there is a cost to add an organic substance such as methanol as an electron donor for the denitrification reaction, and denitrifying bacteria that ingested this organic substance and proliferated become excess sludge, so that the disposal cost of the waste is also increased. There is a problem of being expensive. In particular, nitrate nitrogen is in a more oxidized state as compared with nitrite nitrogen, so the cost of oxygen supply for this is also high, and more electron donors are needed to reduce it. There is also a large amount of excess sludge.
【０００４】これに対して、近年、無酸素条件下でアン
モニア性窒素を電子供与体、亜硝酸性窒素を電子受容体
として両者を反応させ、窒素ガスを生成することができ
る独立栄養性の脱窒微生物群を利用した脱窒方法が知ら
れるようになった（Microbiology 142(1996), p2187-21
96等）。以下ではこの反応をＡＮＡＭＭＯＸ反応と呼
び、この独立栄養性脱窒微生物群をＡＮＡＭＭＯＸ菌と
呼ぶ。この方法によれば、亜硝酸性窒素の持つ酸化力を
利用してアンモニア性窒素を酸化することができるた
め、理論量と同程度の酸素消費量で窒素除去を行うこと
ができ、エネルギーを節約することができる。また、メ
タノール等の有機物を添加する必要がないため、そのた
めのコストも節約できる。この微生物は独立栄養細菌で
あり、有機物を利用して脱窒を行う細菌に比べると、還
元する亜硝酸性窒素当たりに発生する余剰汚泥量が５分
の１以下であり、廃棄物の発生量を大幅に低減すること
ができるという利点もある。On the other hand, in recent years, under anoxic conditions, ammonia nitrogen is used as an electron donor and nitrite nitrogen is used as an electron acceptor to react them with each other to produce nitrogen gas. A denitrification method using nitrifying microorganisms has become known (Microbiology 142 (1996), p2187-21.
96 etc.). Hereinafter, this reaction is referred to as an ANAMMOX reaction, and this autotrophic denitrifying microorganism group is referred to as an ANAMMOX bacterium. According to this method, it is possible to oxidize ammoniacal nitrogen using the oxidizing power of nitrite nitrogen, so nitrogen can be removed with the same amount of oxygen consumption as the theoretical amount, thus saving energy. can do. Further, since it is not necessary to add an organic substance such as methanol, the cost for that can be saved. This microorganism is an autotrophic bacterium. Compared with bacteria that denitrify using organic matter, the amount of excess sludge generated per reducing nitrite nitrogen is one-fifth or less, and the amount of waste generated There is also an advantage that can be significantly reduced.
【０００５】この脱窒反応を行う際に、亜硝酸性窒素は
排水中のアンモニア性窒素の一部を酸化することにより
生成させても良く、また、亜硝酸性窒素を含む他の排水
や薬品を混合しても良い。In carrying out this denitrification reaction, nitrite nitrogen may be generated by oxidizing a part of ammoniacal nitrogen in wastewater, and other wastewater or chemicals containing nitrite nitrogen may be generated. May be mixed.
【０００６】ＡＮＡＭＭＯＸ菌による生物脱窒槽の形式
としては、砂や合成樹脂、ゲルなどの微生物の付着に適
した担体を充填したカラムに上向流で原水を通水し、担
体表面で窒素化合物と微生物を接触させて脱窒反応を進
行させる方式が用いられる。この場合、担体としては比
表面積が大きいものが好適であり、特に粒径０．１〜１
０ｍｍ程度の顆粒状、ひも状、筒状、歯車状などの形状
が知られている。担体は水中で緩やかに流動しているこ
とが好ましく、脱窒により発生するガスや、外部から注
入するガス、撹拌機などにより流動される。As a form of a biological denitrification tank using ANAMMOX bacteria, raw water is passed upward through a column packed with a carrier suitable for adhering microorganisms such as sand, synthetic resin and gel, and nitrogen compounds are formed on the surface of the carrier. A method is used in which microorganisms are brought into contact with each other to progress the denitrification reaction. In this case, a carrier having a large specific surface area is preferable, and a particle size of 0.1 to 1 is particularly preferable.
Shapes of about 0 mm, such as granules, strings, cylinders, and gears, are known. The carrier is preferably gently flowing in water, and is made to flow by a gas generated by denitrification, a gas injected from the outside, a stirrer, or the like.
【０００７】また、水中に浮遊状態で生育する脱窒微生
物を利用することもできる。この場合には、脱窒処理液
を固液分離することにより、系外への微生物の流出を防
止し、系内の微生物濃度を高めることで脱窒槽容積当た
りの反応速度を高めることが好ましい。この場合、固液
分離手段としては、沈殿、浮上、遠心分離、濾過など従
来公知の各種のものが適用可能である。It is also possible to utilize denitrifying microorganisms that grow in a floating state in water. In this case, it is preferable to prevent the outflow of microorganisms to the outside of the system by solid-liquid separating the denitrification treatment liquid and increase the concentration of microorganisms in the system to increase the reaction rate per denitrification tank volume. In this case, as the solid-liquid separation means, various conventionally known means such as precipitation, flotation, centrifugation, and filtration can be applied.
【０００８】ＡＮＡＭＭＯＸ菌の比増殖速度は、最大で
約０．０６５ｄａｙ−１（１日当たり１．０６５倍に増
殖）と遅く、多量の菌体を確保することが非常に困難で
ある。特に、ＡＮＡＭＭＯＸ菌を最大速度で増殖させる
ためには、アンモニア性窒素、亜硝酸性窒素、炭酸根等
のこの菌の基質となる物質を十分に供給する必要がある
が、担体に付着させて増殖させた場合には、付着した生
物膜の内側まで基質を浸透させることが難しく、従って
最大速度よりも遅い速度で増殖させることになり、効率
が悪い。また、生物膜の内側深くまで基質を浸透させる
ためには液中の基質濃度を高く保つ必要があるが、一方
で、基質、特に亜硝酸性窒素が高濃度に存在するとＡＮ
ＡＭＭＯＸ菌が阻害を受け、増殖しなくなったり死滅し
たりして逆効果となる問題もある。また、実際の生物脱
窒装置として稼動させる場合に、担体表面でＡＮＡＭＭ
ＯＸ菌が十分増殖するまでは最大負荷をかけられないた
め、立ち上がりが遅い。これを回避するために予めＡＮ
ＡＭＭＯＸ菌が十分に付着した担体を脱窒槽に投入する
ことも可能であるが、このためには稼動させる生物脱窒
装置と同等の大きさの反応槽で、予めＮＡＭＭＯＸ菌を
培養しておく必要があり、培養装置のコストがかかり、
設置スペースも必要となる。また、培養したＡＮＡＭＭ
ＯＸ菌の運搬費用もかさむ。The specific growth rate of the ANAMMOX bacterium is as slow as about 0.065 day -1 (growth is 1.065 times per day) at the maximum, and it is very difficult to secure a large amount of microbial cells. In particular, in order to grow the ANAMMOX bacterium at the maximum rate, it is necessary to sufficiently supply substances such as ammoniacal nitrogen, nitrite nitrogen, and carbonate radicals that are the substrate of this bacterium, but to grow by attaching it to a carrier. In such a case, it is difficult to permeate the substrate to the inside of the attached biofilm, and therefore the growth rate is slower than the maximum rate, which is inefficient. Further, in order to penetrate the substrate deep inside the biofilm, it is necessary to maintain the substrate concentration in the liquid at a high level. On the other hand, if the substrate, especially nitrite nitrogen, is present at a high concentration, AN
There is also a problem that the AMMOX bacterium is inhibited, and it does not proliferate or is killed, which has the opposite effect. Also, when operating as an actual biological denitrification device, the ANAMM
Since the maximum load cannot be applied until the OX bacterium grows sufficiently, the start-up is slow. In order to avoid this
It is possible to add a carrier with sufficient adherence of AMMOX bacteria to the denitrification tank, but for this purpose, it is necessary to culture NAMMOX bacteria beforehand in a reaction tank of the same size as the biological denitrification device to be operated. There is a cost of the culture device,
Installation space is also required. Also, cultured ANAMM
The cost of transporting OX bacteria is also high.
【０００９】本発明者は、このような、担体を用いてＡ
ＮＡＭＭＯＸ菌の増殖させる場合の問題を解決するため
に検討した結果、ＡＮＡＭＭＯＸ菌を懸濁状態で増殖さ
せて利用することも可能であることを知見した。この場
合には、菌体は粒径０．１ｍｍ以下の比較的小さなフロ
ックを形成しているため、基質の浸透が律速となって増
殖が妨げられることはなく、容易に最大能力を発揮して
脱窒を行うことができる。また、ＡＮＡＭＭＯＸ菌を高
濃度に濃縮させることができるため、装置を立ち上げる
際のＡＮＡＭＭＯＸ菌の供給も容易である。The inventor of the present invention uses such a carrier to
As a result of studies to solve the problem in the case of growing NAMMOX bacteria, it was found that it is also possible to grow and use ANAMMOX bacteria in a suspended state. In this case, since the bacterial cells form relatively small flocs with a particle size of 0.1 mm or less, the permeation of the substrate does not limit the growth and the growth is not hindered. Denitrification can be performed. Moreover, since the ANAMMOX bacteria can be concentrated to a high concentration, it is easy to supply the ANAMMOX bacteria when the apparatus is started up.
【００１０】ＡＮＡＭＭＯＸ菌を懸濁状態で増殖させて
脱窒を行うためには、脱窒処理液から菌体を分離し、濃
縮された菌体を再び脱窒槽へ戻す必要がある。このため
の分離・濃縮手段としては、沈殿、遠心濃縮、濾過、加
圧浮上濃縮等によるものがあるが、このうち最も安価で
操作も簡単なものは沈殿による方法である。[0010] In order to grow the ANAMMOX bacteria in a suspended state for denitrification, it is necessary to separate the cells from the denitrification treatment solution and return the concentrated cells to the denitrification tank again. Separation / concentration means for this purpose include precipitation, centrifugal concentration, filtration, pressure floating concentration, and the like. Of these, the cheapest and simplest operation is the precipitation method.
【００１１】[0011]
【発明が解決しようとする課題】しかしながら、脱窒処
理液からＡＮＡＭＭＯＸ菌を沈殿分離する際、一部は沈
殿しても一部は浮上して系外へ流出するために、高い回
収率で沈殿分離することができず、このためにＡＮＡＭ
ＭＯＸ菌を系内に高濃度に保持することができず、脱窒
性能を高く維持することができないという問題があっ
た。沈殿槽底部での汚泥の滞留時間を２時間以内、好ま
しくは１時間以内とすることで、このような浮上を防止
することができる場合もあったが、確実ではなかった。However, when precipitating and separating the ANAMMOX bacteria from the denitrification treatment liquid, even if a part of it is precipitated, a part of it floats and flows out of the system, so that it is precipitated at a high recovery rate. Can not be separated, because of this ANAM
There was a problem that MOX bacteria could not be maintained in the system at a high concentration and the denitrification performance could not be maintained high. By setting the residence time of the sludge at the bottom of the settling tank to 2 hours or less, preferably 1 hour or less, such floating could be prevented in some cases, but it was not certain.
【００１２】本発明はこのような問題を解決し、ＡＮＡ
ＭＭＯＸ菌を懸濁状態で増殖させて生物脱窒を行い、脱
窒処理液からＡＮＡＭＭＯＸ菌を沈殿分離する際に、沈
殿槽におけるＡＮＡＭＭＯＸ菌の浮上を防止し、系内に
ＡＮＡＭＭＯＸ菌を高濃度に保持することにより効率的
な生物脱窒を行う生物脱窒方法及び生物脱窒装置を提供
することを目的とする。The present invention solves such a problem, and
When the MMOX bacterium is grown in a suspension state for biological denitrification, and when the ANAMMOX bacterium is precipitated and separated from the denitrification treatment liquid, the ANAMMOX bacterium is prevented from floating in the settling tank, and the ANAMMOX bacterium is concentrated in the system at a high concentration. It is an object of the present invention to provide a biological denitrification method and a biological denitrification apparatus that perform efficient biological denitrification by holding the same.
【００１３】[0013]
【課題を解決するための手段】本発明（請求項１）の生
物脱窒方法は、アンモニア性窒素を含有する原水を、ア
ンモニア性窒素を電子供与体とし、亜硝酸性窒素を電子
受容体とする脱窒微生物の作用により亜硝酸性窒素の存
在下に生物脱窒する脱窒工程と、脱窒工程の処理液を固
液分離し、分離液を処理水として排出する固液分離工程
とを有する生物脱窒方法において、固液分離する脱窒工
程の処理液中のアンモニア性窒素濃度と亜硝酸性窒素濃
度の両方又はいずれか一方を０〜５ｍｇ／Ｌとすること
を特徴とする。According to the method of biological denitrification of the present invention (claim 1), raw water containing ammoniacal nitrogen is used as an electron donor with ammoniacal nitrogen and as an electron acceptor with nitrite nitrogen. The denitrification step of biologically denitrifying in the presence of nitrite nitrogen by the action of the denitrifying microorganisms, and the solid-liquid separation step of solid-liquid separation of the treatment liquid of the denitrification step and discharging the separated liquid as treated water. In the biological denitrification method, the method is characterized in that both or either of the concentration of ammonia nitrogen and the concentration of nitrite nitrogen in the treatment liquid in the denitrification step of solid-liquid separation are set to 0 to 5 mg / L.
【００１４】本発明（請求項２）の生物脱窒方法は、ア
ンモニア性窒素を含有する原水を、アンモニア性窒素を
電子供与体とし、亜硝酸性窒素を電子受容体とする脱窒
微生物の作用により亜硝酸性窒素の存在下に生物脱窒す
る脱窒槽に導入して脱窒処理し、該脱窒槽の流出液を沈
殿槽に導入して固液分離し、分離液を処理水として排出
すると共に分離汚泥を前記脱窒槽に返送する生物脱窒方
法において、脱窒槽を複数直列に設け、最後段の脱窒槽
の流出液を該沈殿槽に導入することを特徴とする。The biological denitrification method of the present invention (claim 2) is an action of a denitrifying microorganism in which raw water containing ammoniacal nitrogen is used as an electron donor with ammoniacal nitrogen and with nitrite nitrogen as an electron acceptor. By introducing into a denitrification tank for biological denitrification in the presence of nitrite nitrogen for denitrification treatment, introducing the effluent of the denitrification tank into a precipitation tank for solid-liquid separation, and discharging the separated liquid as treated water. In the biological denitrification method in which the separated sludge is returned to the denitrification tank, a plurality of denitrification tanks are provided in series, and the effluent of the final denitrification tank is introduced into the settling tank.
【００１５】本発明の生物脱窒装置は、アンモニア性窒
素を含有する原水の流入口と処理液の流出口を有し、ア
ンモニア性窒素を電子供与体とし、亜硝酸性窒素を電子
受容体とする脱窒微生物の作用により原水を亜硝酸性窒
素の存在下に生物脱窒する複数の脱窒槽と、該脱窒槽の
処理液を固液分離する沈殿槽と、該沈殿槽で分離された
分離液を処理水として排出する手段と、該沈殿槽で分離
された分離汚泥を前記第１の脱窒槽へ返送する手段とを
備えてなり、前記複数の脱窒槽は、前段側の脱窒槽の処
理水が後段側の脱窒槽に導入されて脱窒処理されるよう
に直列に接続されており、最終段の脱窒槽の処理液が前
記沈殿槽に導入されることを特徴とする。The biological denitrification apparatus of the present invention has an inlet for raw water containing ammoniacal nitrogen and an outlet for the treatment liquid, and uses ammoniacal nitrogen as an electron donor and nitrite nitrogen as an electron acceptor. A plurality of denitrification tanks for biologically denitrifying raw water in the presence of nitrite nitrogen by the action of denitrifying microorganisms, a settling tank for solid-liquid separation of a treatment liquid of the denitrification tank, and a separation separated in the settling tank And a means for returning the separated sludge separated in the settling tank to the first denitrification tank, wherein the plurality of denitrification tanks are used for processing the denitrification tank on the preceding stage side. Water is connected in series so as to be introduced into the denitrification tank on the latter stage side and subjected to denitrification treatment, and the treatment liquid of the denitrification tank on the final stage is introduced to the precipitation tank.
【００１６】ＡＮＡＭＭＯＸ菌のフロックや、ＡＮＡＭ
ＭＯＸ菌が付着した担体が沈殿槽で浮上する原因は、沈
殿槽内に存在するアンモニア性窒素及び亜硝酸性窒素に
より、沈殿槽内でＡＮＡＭＭＯＸ反応が生じ、窒素ガス
が生成することにあると考えられる。Flock of ANAMMOX bacteria and ANAM
It is considered that the reason why the carrier having MOX bacteria attached thereto floats in the settling tank is that the ammonia nitrogen and the nitrite nitrogen existing in the settling tank cause the ANAMMOX reaction in the settling tank to generate nitrogen gas. To be
【００１７】また、回分式の場合にも、脱窒工程におけ
る処理液のアンモニア性窒素濃度と亜硝酸性窒素濃度の
いずれか一方或いは各々両方を５ｍｇ／Ｌ以下となるま
で脱窒処理を行った後、固液分離工程に移行することに
より、ＡＮＡＭＭＯＸ菌の浮上を防止することができ
る。Also in the case of the batch type, the denitrification treatment was performed until one or both of the ammonia nitrogen concentration and the nitrite nitrogen concentration of the treatment liquid in the denitrification step became 5 mg / L or less. After that, by moving to the solid-liquid separation step, it is possible to prevent the floating of ANAMMOX bacteria.
【００１８】本発明者の検討によれば、アンモニア性窒
素濃度及び亜硝酸性窒素濃度が共に５ｍｇ／Ｌ以上の時
に、このような現象が顕著であった。According to the study by the present inventor, such a phenomenon was remarkable when both the ammonia nitrogen concentration and the nitrite nitrogen concentration were 5 mg / L or more.
【００１９】本発明の請求項１の生物脱窒方法では、沈
殿槽に導入する脱窒槽の流出液のアンモニア性窒素濃度
と亜硝酸性窒素濃度のいずれか一方或いは各々両方を５
ｍｇ／Ｌ以下とし、アンモニア性窒素と亜硝酸性窒素と
のＡＮＡＭＭＯＸ反応による窒素ガスの生成を防止する
ことにより、ＡＮＡＭＭＯＸ菌の浮上を防止する。In the biological denitrification method according to claim 1 of the present invention, one or both of the concentration of ammonia nitrogen and the concentration of nitrite nitrogen in the effluent of the denitrification tank introduced into the precipitation tank are adjusted to 5%.
It is set to be mg / L or less, and by preventing the production of nitrogen gas by the ANAMMOX reaction of ammoniacal nitrogen and nitrite nitrogen, the floating of ANAMMOX bacteria is prevented.
【００２０】なお、通常、活性汚泥を沈殿させる際、硝
酸性窒素が５〜１０ｍｇ／Ｌ共存すると、活性汚泥が内
性呼吸による還元反応によりこれらの硝酸性窒素を脱窒
し、窒素ガスを発生して浮上するという報告もあるが、
ＡＮＡＭＭＯＸ菌の場合には硝酸性窒素を脱窒しないた
めに、硝酸性窒素は１０ｍｇ／Ｌ以上存在しても汚泥が
浮上することはない。但し、ＡＮＡＭＭＯＸ菌と共に、
脱窒を行う従属栄養微生物が系内に多く存在する場合
は、硝酸性窒素の脱窒による窒素ガス発生に起因する汚
泥の浮上を防止するために、硝酸性窒素を５ｍｇ／Ｌ以
下とするのが好ましい。[0020] Usually, when nitrate nitrogen coexists in an amount of 5 to 10 mg / L when the activated sludge is precipitated, the activated sludge denitrifies the nitrate nitrogen by a reduction reaction due to internal respiration, and nitrogen gas is generated. Although there are reports that it will surface,
In the case of ANAMMOX bacteria, since nitrate nitrogen is not denitrified, sludge does not float even if nitrate nitrogen is present at 10 mg / L or more. However, along with the ANAMMOX bacterium,
When a large amount of heterotrophic microorganisms that perform denitrification are present in the system, the nitrate nitrogen should be 5 mg / L or less in order to prevent the sludge from floating due to nitrogen gas generation due to the denitrification of nitrate nitrogen. Is preferred.
【００２１】このような従属栄養微生物の存在量の判定
を行うためには、グルコースやエタノール、メタノー
ル、酢酸等の有機物を添加して、ＶＳＳ（懸濁物質の強
熱減量）当たりの脱窒速度が０．００５〜０．０２ｋｇ
−Ｎ／ｋｇ−ＶＳＳ／ｄａｙ又はそれ以上の脱窒能力を
持つ場合には、従属栄養微生物が多いと判断することが
できる。ただし、内生呼吸のレベルによっては問題とな
らない場合もあり、また、沈殿槽の滞留時間又は沈殿し
た汚泥の濃度によって汚泥の浮上性は左右されるため、
これらを総合的に考慮するのが好ましい。In order to determine the abundance of such heterotrophic microorganisms, organic substances such as glucose, ethanol, methanol and acetic acid are added, and the denitrification rate per VSS (loss on ignition of suspended matter) is determined. Is 0.005-0.02 kg
When it has a denitrification ability of -N / kg-VSS / day or higher, it can be determined that there are many heterotrophic microorganisms. However, it may not be a problem depending on the level of endogenous respiration, and since the sludge floatability is affected by the residence time in the settling tank or the concentration of the sludge that has settled,
It is preferable to consider these comprehensively.
【００２２】このように沈殿槽に流入する液のアンモニ
ア性窒素及び／又は亜硝酸性窒素濃度を５ｍｇ／Ｌ以下
とする場合、脱窒槽を１槽のみ用いても良いが、脱窒槽
内は通常完全混合に近い状態に撹拌されるため、脱窒槽
内の液もアンモニア性窒素濃度及び／又は亜硝酸性窒素
濃度が５ｍｇ／Ｌ以下となり、ＡＮＡＭＭＯＸ菌と接触
するこれらの基質との親和性が律速となってＡＮＡＭＭ
ＯＸ菌が最大能力を発揮できない場合がある。特に、脱
窒槽内の部分的に撹拌状態の悪いところでは、これらの
いずれかの基質が欠乏し、脱窒槽内のＡＮＡＭＭＯＸ菌
の全てを有効に利用できないという不具合が発生し易
い。When the concentration of ammonia nitrogen and / or nitrite nitrogen in the liquid flowing into the settling tank is 5 mg / L or less, only one denitrification tank may be used, but the inside of the denitrification tank is usually Since the mixture is agitated in a state close to perfect mixing, the concentration of ammonia nitrogen and / or nitrite nitrogen in the denitrification tank is 5 mg / L or less, and the affinity with these substrates that come into contact with ANAMMOX bacteria is rate-determining. Become ANAMM
In some cases, OX bacteria cannot exert their maximum capacity. In particular, in a part where the stirring condition is partially poor in the denitrification tank, one of these substrates is deficient, and the problem that all the ANAMMOX bacteria in the denitrification tank cannot be effectively used tends to occur.
【００２３】これに対して、本発明の請求項２の方法又
は請求項５の装置により、脱窒槽を２槽以上の直列配置
とすれば、沈殿槽直前の１槽を除く脱窒槽には十分に基
質を供給し、基質律速とならない条件でＡＮＡＭＭＯＸ
反応を行わせることができる。このためにＡＮＡＭＭＯ
Ｘ菌を最大能力付近まで有効に活用することが可能とな
る。一方、沈殿槽直前の脱窒槽では、前段で取り残した
基質を十分に除去する余裕を持たせることができるため
に、沈殿槽にはアンモニア性窒素と亜硝酸性窒素の少な
くとも一方を十分に低濃度として供給することができ、
汚泥浮上の問題を確実に回避して安定した沈降分離を行
うことが可能となる。On the other hand, if two or more denitrification tanks are arranged in series by the method according to claim 2 of the present invention or the device according to claim 5, it is sufficient for the denitrification tank except one tank immediately before the precipitation tank. Substrate is supplied to the ANAMMOX under conditions that do not control the substrate
The reaction can be carried out. For this purpose ANAMMO
It is possible to effectively utilize the X bacteria up to near the maximum capacity. On the other hand, in the denitrification tank immediately before the settling tank, it is possible to sufficiently allow the substrate left behind in the previous stage to be removed, so that at least one of ammonia nitrogen and nitrite nitrogen is sufficiently low in the settling tank. Can be supplied as
It is possible to reliably avoid the problem of floating sludge and perform stable sedimentation separation.
【００２４】また、脱窒槽を複数直列に設けた場合にお
いて、請求項４の方法又は請求項６の装置により、原水
を分割注入することにより、上流側の脱窒槽が原水によ
り希釈されるのを防止して、ＡＮＡＭＭＯＸ菌濃度を高
く保つことができるために、容積当たりの反応速度を高
く取ることが可能となり、槽容積を小さくすることがで
きる。When a plurality of denitrification tanks are provided in series, the raw water is dividedly injected by the method according to claim 4 or the apparatus according to claim 6, whereby the upstream denitrification tank is diluted with the raw water. Since the concentration of ANAMMOX bacteria can be kept high by preventing it, the reaction rate per volume can be made high, and the volume of the tank can be reduced.
【００２５】即ち、例えば、沈殿槽からの返送汚泥濃度
が２０，０００ｍｇ／Ｌであり、原水量が返送汚泥量の
３倍であった場合、原水と返送汚泥の全てを第１段目の
脱窒槽に投入すると、汚泥濃度は原水により希釈され、
５０００ｍｇ／Ｌとなる。このとき、ＶＳＳ当たりのア
ンモニア性窒素除去能力が０．２ｋｇ−Ｎ／ｋｇ−ＶＳ
Ｓ／ｄａｙであったとすると、容積当たりのアンモニア
性窒素除去能力は１ｋｇ−Ｎ／ｍ３／ｄａｙとなる。That is, for example, when the concentration of sludge returned from the settling tank is 20,000 mg / L and the amount of raw water is three times the amount of returned sludge, all of the raw water and the returned sludge are removed from the first stage. When put in a nitrification tank, the sludge concentration is diluted with raw water,
It becomes 5000 mg / L. At this time, the ammonia nitrogen removal capacity per VSS is 0.2 kg-N / kg-VS.
If it is S / day, the ammoniacal nitrogen removal capacity per volume will be 1 kg-N / m 3 / day.
【００２６】これに対して、４槽直列に配置した等容積
の脱窒槽の第１段目から第３段目までの３槽に原水を３
等分して投入し、返送汚泥を第１段目の脱窒槽に投入す
ると、第１段目の脱窒槽の汚泥濃度は１０，０００ｍｇ
／Ｌ、容積当たりのアンモニア性窒素除去速度は２ｋｇ
−Ｎ／ｍ３／ｄａｙとなり、第２段目の脱窒槽では汚泥
濃度６６７０ｍｇ／Ｌ、容積当たりのアンモニア性窒素
除去速度１．３３ｋｇ−Ｎ／ｍ３／ｄａｙ、第３段目〜
第４段目の脱窒槽では汚泥濃度５０００ｍｇ／Ｌ、容積
当たりのアンモニア性窒素除去速度１ｋｇ−Ｎ／ｍ３／
ｄａｙとなる。この場合には、分割注入を行った場合の
４槽分の平均の負荷は１．３３（＝（２＋１．３３＋１
＋１）÷４）ｋｇ−Ｎ／ｍ３／ｄａｙとなり、脱窒槽の
合計容積を約２５％（＝（１−１／１．３３）×１０
０）縮減することができる。On the other hand, the raw water is added to three tanks from the first stage to the third stage of the denitrification tanks of equal volume arranged in series in four tanks.
When the returned sludge was added to the first denitrification tank in equal parts, the sludge concentration in the first denitrification tank was 10,000 mg.
/ L, ammonia nitrogen removal rate per volume is 2 kg
-N / m 3 / day, sludge concentration 6670 mg / L in the second stage denitrification tank, ammonia nitrogen removal rate per volume 1.33 kg-N / m 3 / day, 3rd stage ~
In the fourth stage denitrification tank, the sludge concentration was 5000 mg / L, and the ammonia nitrogen removal rate per volume was 1 kg-N / m 3 /
It becomes day. In this case, the average load for the four tanks when performing the split injection is 1.33 (= (2 + 1.33 + 1
+1) ÷ 4) kg-N / m 3 / day, and the total volume of the denitrification tank is about 25% (= (1-1 / 1.33) × 10
0) It can be reduced.
【００２７】[0027]
【発明の実施の形態】以下に図面を参照して本発明の生
物脱窒方法及び生物脱窒装置の実施の形態を詳細に説明
する。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the biological denitrification method and biological denitrification apparatus of the present invention will be described in detail below with reference to the drawings.
【００２８】図１は本発明の生物脱窒装置の実施の形態
を示す系統図である。FIG. 1 is a system diagram showing an embodiment of the biological denitrification apparatus of the present invention.
【００２９】この生物脱窒装置は、第１の脱窒槽１と、
第２の脱窒槽２と沈殿槽３とで主に構成される。第１の
脱窒槽１及び第２の脱窒槽２にはそれぞれ撹拌機１Ｍ，
２Ｍが設けられ、沈殿槽３には脱窒処理液が流入するフ
ィードウェル３Ｆと集泥用のレーキ３Ｍが設けられてい
る。これら脱窒槽１，２及び沈殿槽３は密閉構造とされ
ており、各槽１，２，３から脱窒ガスを排出する脱窒ガ
ス排出管１５ａ，１５ｂ，１５Ａ，１５Ｂ及び１５が設
けられている。This biological denitrification device comprises a first denitrification tank 1 and
It is mainly composed of the second denitrification tank 2 and the precipitation tank 3. The first denitrification tank 1 and the second denitrification tank 2 each have a stirrer 1M,
2M is provided, and the settling tank 3 is provided with a feed well 3F into which the denitrification treatment liquid flows and a rake 3M for collecting mud. The denitrification tanks 1 and 2 and the precipitation tank 3 have a closed structure, and are provided with denitrification gas discharge pipes 15a, 15b, 15A, 15B and 15 for discharging denitrification gas from the tanks 1, 2 and 3, respectively. There is.
【００３０】原水は原水流入管１１より第１の脱窒槽１
に導入され、脱窒処理された後、連通管１２より第２の
脱窒槽２に移送される。第２の脱窒槽２の脱窒処理液は
連通管１３より沈殿槽３に移送され沈殿分離される。沈
殿槽３で分離された分離液は処理水流出管１４より処理
水として系外へ排出され、分離汚泥はポンプＰを備える
汚泥返送管１５により第１の脱窒槽１に返送される。Raw water is fed from the raw water inflow pipe 11 to the first denitrification tank 1
And is denitrified, and then transferred to the second denitrification tank 2 through the communication pipe 12. The denitrification treatment liquid in the second denitrification tank 2 is transferred to the settling tank 3 through the communication pipe 13 and separated by sedimentation. The separated liquid separated in the settling tank 3 is discharged out of the system as treated water through the treated water outflow pipe 14, and the separated sludge is returned to the first denitrification tank 1 through a sludge return pipe 15 equipped with a pump P.
【００３１】本発明においては、このような生物脱窒装
置により、第２の脱窒槽２から沈殿槽３に流入する脱窒
処理液のアンモニア性窒素濃度と亜硝酸性窒素濃度のい
ずれか一方又は双方を５ｍｇ／Ｌ以下、好ましくは３ｍ
ｇ／Ｌ以下、より好ましくは１ｍｇ／Ｌ以下となるよう
に負荷、その他の条件を調整する。沈殿槽３に流入する
脱窒処理液のアンモニア性窒素濃度及び亜硝酸性窒素濃
度が共に５ｍｇ／Ｌを超えると、沈殿槽３においてＡＮ
ＡＭＭＯＸ菌による脱窒反応が進行し、発生する窒素ガ
スにより汚泥の浮上、流出の問題が生じる。In the present invention, with such a biological denitrification device, either one of the ammonia nitrogen concentration and the nitrite nitrogen concentration of the denitrification treatment liquid flowing from the second denitrification tank 2 into the settling tank 3 or 5 mg / L or less for both, preferably 3 m
The load and other conditions are adjusted so as to be g / L or less, more preferably 1 mg / L or less. When both the ammonia nitrogen concentration and the nitrite nitrogen concentration of the denitrification treatment liquid flowing into the settling tank 3 exceed 5 mg / L, the AN in the settling tank 3 is increased.
The denitrification reaction by the AMMOX bacteria progresses, and the nitrogen gas generated causes a problem of floating and outflow of sludge.
【００３２】なお、ＡＮＡＭＭＯＸ菌による脱窒処理で
は、硝酸性窒素が生成するため、通常の場合、図１に示
すような生物脱窒装置の後段には硝酸性窒素を除去する
ための脱窒装置が設けられ、沈殿槽３からの処理水は更
に脱窒処理される。この脱窒処理においては、亜硝酸性
窒素も同時に除去される。従って、処理水中に亜硝酸性
窒素が残留しても後段の脱窒装置で除去できるが、アン
モニア性窒素が残留した場合には、更に残留するアンモ
ニア性窒素を除去するための硝化脱窒装置を設ける必要
が生じることから、本発明では、亜硝酸性窒素よりもア
ンモニア性窒素を低濃度に維持することが後段での処理
水質の向上や装置構成の簡略化の面で好ましい。従っ
て、一般的には、沈殿槽３に流入する脱窒処理液のアン
モニア性窒素濃度が５ｍｇ／Ｌ以下、好ましくは３ｍｇ
／Ｌ以下、より好ましくは１ｍｇ／Ｌ以下となるように
処理を行うのが好ましい。特に、この濃度を１ｍｇ／Ｌ
以下とした場合には、沈殿槽における汚泥の滞留時間を
２４時間程度の長い時間にした場合でも、汚泥の浮上を
確実に防止することができる。In the denitrification treatment with ANAMMOX bacterium, nitrate nitrogen is produced. Therefore, in the usual case, a denitrification device for removing nitrate nitrogen is usually provided at the subsequent stage of the biological denitrification device as shown in FIG. Is provided, and the treated water from the settling tank 3 is further denitrified. In this denitrification process, nitrite nitrogen is also removed at the same time. Therefore, even if nitrite nitrogen remains in the treated water, it can be removed by the denitrification device at the subsequent stage, but if ammonia nitrogen remains, a nitrification denitrification device for removing the remaining ammonia nitrogen should be installed. In the present invention, it is preferable to maintain the ammoniacal nitrogen at a lower concentration than the nitrite nitrogen, from the viewpoints of improving the quality of treated water in the latter stage and simplifying the configuration of the apparatus. Therefore, generally, the concentration of ammonia nitrogen in the denitrification treatment liquid flowing into the settling tank 3 is 5 mg / L or less, preferably 3 mg.
/ L or less, more preferably 1 mg / L or less. Especially, this concentration is 1mg / L
In the following cases, even if the sludge retention time in the settling tank is set to a long time of about 24 hours, it is possible to reliably prevent the sludge from floating.
【００３３】このような本発明の方法を効果的に実施す
るためには、沈殿槽３の入口におけるアンモニア性窒素
濃度及び／又は亜硝酸性窒素濃度を監視し、アンモニア
性窒素濃度を低く保つ場合において、沈殿槽３入口のア
ンモニア性窒素濃度が高いようであれば、この生物脱窒
装置に流入するアンモニア性窒素負荷を下げるか亜硝酸
性窒素負荷を上げる操作を行い、亜硝酸性窒素濃度を低
く保つ場合において、沈殿槽３入口の亜硝酸性窒素濃度
が高いようであれば、この生物脱窒装置に流入する亜硝
酸性窒素負荷を下げるかアンモニア性窒素負荷を上げる
操作を行えば良い。In order to effectively carry out such a method of the present invention, when the ammonia nitrogen concentration and / or the nitrite nitrogen concentration at the inlet of the precipitation tank 3 are monitored and the ammonia nitrogen concentration is kept low. If the ammonia nitrogen concentration at the inlet of the precipitation tank 3 seems to be high, the operation to reduce the ammonia nitrogen load flowing into this biological denitrification device or increase the nitrite nitrogen load is performed to determine the nitrite nitrogen concentration. If the concentration of nitrite nitrogen at the inlet of the precipitation tank 3 seems to be high in the case of keeping it low, the operation of reducing the nitrite nitrogen load flowing into this biological denitrification device or increasing the ammonia nitrogen load may be performed.
【００３４】なお、沈殿槽３入口のアンモニア性窒素濃
度及び亜硝酸性窒素濃度のいずれか一方が十分に低い場
合でも他方の残留濃度が大きく、全窒素濃度が高い場合
には、不足している側の窒素負荷を上げるか、過剰とな
っている側の窒素負荷を下げることにより全窒素濃度を
下げることが望ましい。Even if either the concentration of ammonia nitrogen or the concentration of nitrite nitrogen at the inlet of the precipitation tank 3 is sufficiently low, the residual concentration of the other is large, and if the total nitrogen concentration is high, it is insufficient. It is desirable to lower the total nitrogen concentration by increasing the nitrogen load on the side or reducing the nitrogen load on the side that is excessive.
【００３５】このような負荷調整は、沈殿槽の前段の脱
窒槽におけるＡＮＡＭＭＯＸ反応速度や流入する原水の
アンモニア性窒素と亜硝酸性窒素との比率が既知である
か、容易に推測できる場合には、このような濃度測定を
行わずに机上計算のみで対応することもできる。Such load adjustment is carried out when the ANAMMOX reaction rate in the denitrification tank before the settling tank and the ratio of ammonia nitrogen and nitrite nitrogen in the raw water flowing in are known or can be easily estimated. , It is also possible to deal with it only by the desk calculation without performing such concentration measurement.
【００３６】沈殿槽３の入口での濃度の監視は一定時間
毎に手動又は自動の水質分析、好ましくは自動の水質分
析により行われる。このための測定手段としては、特に
制限はなく、フローインジェクション法による測定手
段、イオン電極による測定手段、紫外線分析計による測
定手段、その他従来公知の測定手段をいずれも用いるこ
とができる。Monitoring of the concentration at the inlet of the settling tank 3 is carried out at regular intervals by manual or automatic water quality analysis, preferably automatic water quality analysis. The measuring means for this purpose is not particularly limited, and any of measuring means by a flow injection method, measuring means by an ion electrode, measuring means by an ultraviolet analyzer, and other conventionally known measuring means can be used.
【００３７】原水の水質や脱窒槽の運転条件が安定して
いる場合には、一旦沈殿槽入口のアンモニア性窒素濃度
及び／又は亜硝酸性窒素濃度を調整した後は、通常一定
期間は同様の状態を維持できるため、負荷調整は必ずし
も毎日行う必要はなく、半年程度調整が不要な場合もあ
る。When the water quality of the raw water and the operating conditions of the denitrification tank are stable, once the ammonia nitrogen concentration and / or the nitrite nitrogen concentration at the inlet of the precipitation tank are adjusted, the same conditions are usually maintained for a certain period. Since the condition can be maintained, it is not always necessary to adjust the load every day, and in some cases it may not be necessary to adjust the load for about six months.
【００３８】第１の脱窒槽１及び第２の脱窒槽２には、
ＡＮＡＭＭＯＸ菌が懸濁状態で保持されるが、ＡＮＡＭ
ＭＯＸ菌は水よりもわずかに重い比重の担体、例えば比
重１．００１〜１．５程度の担体に付着増殖させても良
い。In the first denitrification tank 1 and the second denitrification tank 2,
ANAMMOX bacteria are retained in suspension, but
The MOX bacterium may be allowed to adhere and grow on a carrier having a specific gravity slightly heavier than water, for example, a carrier having a specific gravity of about 1.001 to 1.5.
【００３９】ＡＮＡＭＭＯＸ菌は通常ＶＳＳとして脱窒
槽内に５００〜２０，０００ｍｇ／Ｌ程度、好ましくは
１０００〜８０００ｍｇ／Ｌ程度保持される。The ANAMMOX bacterium is usually kept as VSS in the denitrification tank at about 500 to 20,000 mg / L, preferably about 1000 to 8000 mg / L.
【００４０】このようなＡＮＡＭＭＯＸ菌に対する負荷
はアンモニア性窒素として０．０２〜１．０ｋｇ／ｋｇ
−ＶＳＳ／ｄａｙ程度、特に０．０６〜０．５ｋｇ／ｋ
ｇ−ＶＳＳ／ｄａｙ程度であることが好ましい。ＡＮＡ
ＭＭＯＸ反応でアンモニア性窒素と反応する亜硝酸性窒
素はアンモニア性窒素の約１．３倍であるため、通常
は、アンモニア性窒素の負荷に応じてその１．３倍程度
の亜硝酸性窒素が負荷されるが、いずれか一方が過剰に
負荷される場合もある。The load on the ANAMMOX bacteria is 0.02-1.0 kg / kg as ammoniacal nitrogen.
-VSS / day level, especially 0.06-0.5 kg / k
It is preferably about g-VSS / day. ANA
Since the nitrite nitrogen that reacts with ammoniacal nitrogen in the MMOX reaction is about 1.3 times that of ammoniacal nitrogen, normally, about 1.3 times that amount of nitrite nitrogen is changed depending on the load of ammoniacal nitrogen. It is loaded, but either one may be overloaded.
【００４１】脱窒槽の容積当たりの負荷は、一般にアン
モニア性窒素として０．０１〜２０ｋｇ／ｍ３／ｄａｙ
であり、好ましくは０．０２〜２ｋｇ／ｍ３／ｄａｙで
あるが、脱窒槽に流入するアンモニア性窒素及び亜硝酸
性窒素量に対して、脱窒槽中にＡＮＡＭＭＯＸ菌以外の
懸濁物質が多いほど採用し得る負荷は低くなり、また、
ＢＯＤや硫黄化合物、鉄化合物などの脱窒槽内でＡＮＡ
ＭＭＯＸ菌以外の菌体のエネルギー源となり、これらの
菌体を増殖させる物質が多く含まれているほど採用し得
る負荷は低くなる。The load per volume of the denitrification tank is generally 0.01 to 20 kg / m 3 / day as ammoniacal nitrogen.
And preferably 0.02 to 2 kg / m 3 / day, but there are many suspended substances other than ANAMMOX bacteria in the denitrification tank with respect to the amount of ammonia nitrogen and nitrite nitrogen flowing into the denitrification tank. The lower the load that can be adopted, the more
ANA in the denitrification tank for BOD, sulfur compounds, iron compounds, etc.
It becomes an energy source for cells other than MMOX bacteria, and the more substances that grow these cells are contained, the lower the load that can be adopted.
【００４２】濃縮されたＡＮＡＭＭＯＸ菌を含む沈殿槽
３の分離汚泥は、上流の任意の脱窒槽に返送することが
できるが、一般的には最も上流側の脱窒槽１に返送する
のが好ましい。この汚泥返送方法としては、渦巻きポン
プやスネークポンプ、ガスリフトポンプ等の従来公知の
いずれの手段を採用しても良いが、特に担体を用いた場
合には、開口部の大きいガスリフトポンプを用いるのが
好ましい。この場合、ガスリフトポンプに吹き込むガス
は酸素を含有しないガスであることが好ましく、ＡＮＡ
ＭＭＯＸ反応により生成した窒素ガスを主体とするガス
などが好適に用いられる。The separated sludge in the sedimentation tank 3 containing the concentrated ANAMMOX bacteria can be returned to any upstream denitrification tank, but it is generally preferable to return it to the most upstream denitrification tank 1. As the sludge returning method, any conventionally known means such as a centrifugal pump, a snake pump, and a gas lift pump may be adopted, but when a carrier is used, a gas lift pump with a large opening is used. preferable. In this case, the gas blown into the gas lift pump is preferably a gas containing no oxygen.
A gas mainly containing nitrogen gas produced by the MMOX reaction is preferably used.
【００４３】なお、空気等の酸素含有ガスであっても、
エアリフトポンプ通過後に窒素ガスと接触させたり、亜
硫酸塩などの脱酸素剤を加えたり、従属栄養細菌の作用
でＤＯ濃度を下げるなどの処理を施すことにより、返送
汚泥を速やかに無酸素状態に戻すことにより、使用する
ことができる。Even if the gas contains oxygen, such as air,
The returned sludge can be quickly returned to anoxic state by contacting it with nitrogen gas after passing through the air lift pump, adding a deoxidizer such as sulfite, and reducing DO concentration by the action of heterotrophic bacteria. Therefore, it can be used.
【００４４】沈殿槽３の水面積負荷又は上昇流速は０．
１〜１００ｍ／ｄａｙ、特に３〜２０ｍ／ｄａｙとする
のが好ましく、汚泥の滞留時間は０．５〜２４時間、特
に１〜１２時間程度とするのが好ましい。The water area load or the rising flow velocity of the settling tank 3 is 0.
It is preferably 1 to 100 m / day, particularly 3 to 20 m / day, and the retention time of sludge is preferably 0.5 to 24 hours, particularly preferably 1 to 12 hours.
【００４５】本発明においては、沈殿槽に流入する脱窒
処理液のアンモニア性窒素濃度又は亜硝酸性窒素濃度の
いずれか一方又は双方を低く抑えることで、このような
条件において、沈殿槽における汚泥の浮上、流出を確実
に防止することができる。In the present invention, by controlling either one or both of the ammonia nitrogen concentration and the nitrite nitrogen concentration of the denitrification treatment liquid flowing into the settling tank to be low, the sludge in the settling tank is set under such conditions. It is possible to surely prevent the floating and the outflow.
【００４６】図１の生物脱窒装置は、２槽の脱窒槽を直
列に設けたものであるが、本発明の方法は図２に示す如
く、脱窒槽を１槽のみ設けた生物脱窒装置であっても実
施することができる。なお、図２の生物脱窒装置は図１
の生物脱窒装置における第２の脱窒槽を省略したもので
あり、図２において、図１の生物脱窒装置と同一機能を
奏する部材には同一符号を付してある。Although the biological denitrification apparatus of FIG. 1 is provided with two denitrification tanks in series, the method of the present invention is a biological denitrification apparatus having only one denitrification tank as shown in FIG. Can be implemented even if. The biological denitrification device in FIG. 2 is shown in FIG.
The second denitrification tank in the biological denitrification device of 1 is omitted, and in FIG. 2, members having the same functions as those of the biological denitrification device of FIG. 1 are denoted by the same reference numerals.
【００４７】ただし、沈殿槽に流入する脱窒処理液のア
ンモニア性窒素濃度又は亜硝酸性窒素濃度と窒素負荷の
制御の点からは、２槽以上の脱窒槽を直列に設けた生物
脱窒装置が好適に使用される。この場合、脱窒槽の数が
過度に多くても生物脱窒装置が過大となり好ましくな
い。一般的には、１０槽以下、特に２〜６槽の脱窒槽を
用いるのが好ましい。また、脱窒槽は２槽以上直列に配
置される部分があれば良く、２槽以上の脱窒槽が並列に
設置されている部分があっても良い。However, from the viewpoint of controlling the nitrogen load and the ammonia nitrogen concentration or nitrite nitrogen concentration of the denitrification treatment liquid flowing into the settling tank, a biological denitrification apparatus having two or more denitrification tanks in series is provided. Is preferably used. In this case, even if the number of denitrification tanks is excessively large, the biological denitrification device becomes excessively large, which is not preferable. Generally, it is preferable to use a denitrification tank having 10 or less tanks, particularly 2 to 6 tanks. Further, the denitrification tank may have a portion where two or more tanks are arranged in series, and may have a portion where two or more tanks are arranged in parallel.
【００４８】２槽以上の脱窒槽を直列に設ける場合、前
述の如く、沈殿槽からの返送汚泥は最も上流側の脱窒槽
に返送するのが好ましい。When two or more denitrification tanks are provided in series, it is preferable that the sludge returned from the settling tank is returned to the most upstream denitrification tank as described above.
【００４９】また、このように２槽以上の脱窒槽を直列
に設けた場合、原水は第１段目の脱窒槽のみに導入する
場合に限らず、複数の脱窒槽に分割して導入しても良
く、この場合には高濃縮されたＡＮＡＭＭＯＸ菌を含む
返送汚泥が第１段目の脱窒槽で原水により低濃度に希釈
されるのを防止することができ、生物脱窒装置全体の容
積負荷を大きくして生物脱窒装置を小型化することがで
きる。ただし、沈殿槽の直前の脱窒槽には、原水を導入
しないか、或いは導入する場合でも、他の脱窒槽よりも
少なくすることが好ましく、従って、沈殿槽の直前の脱
窒槽以外の脱窒槽に、下流側の脱窒槽ほど原水流入量が
少なくなるように、原水を分割注入するのが好ましい。When two or more denitrification tanks are provided in series in this way, the raw water is not limited to being introduced into only the first-stage denitrification tank, and the raw water may be divided into a plurality of denitrification tanks and introduced. In this case, it is possible to prevent the returned sludge containing highly concentrated ANAMMOX bacteria from being diluted to a low concentration by the raw water in the first-stage denitrification tank. The size of the biological denitrification device can be increased by downsizing. However, it is preferable not to introduce raw water into the denitrification tank immediately before the settling tank, or even if it is introduced, the raw water should be smaller than other denitrification tanks. It is preferable that the raw water is dividedly injected so that the raw water inflow amount becomes smaller in the downstream denitrification tank.
【００５０】なお、２槽以上の脱窒槽を直列に設ける場
合、各槽の容積比は、原水の分割注入の有無、原水水
質、目標とする水質、各槽の負荷等に応じて適宜決定さ
れる。When two or more denitrification tanks are provided in series, the volume ratio of each tank is appropriately determined according to the presence or absence of split injection of raw water, raw water quality, target water quality, load of each tank, etc. It
【００５１】本発明において、脱窒槽内にはＡＮＡＭＭ
ＯＸ菌以外の他の脱窒細菌や硝化細菌、その他の菌体や
活性汚泥が存在しても良く、脱窒槽において、これらの
菌体によりＡＮＡＭＭＯＸ反応以外の反応を行わせても
良い。特に脱窒細菌との組み合わせは好適である。In the present invention, ANAMM is provided in the denitrification tank.
Other denitrifying bacteria other than OX bacteria, nitrifying bacteria, other fungi and activated sludge may be present, and in the denitrification tank, these fungi may perform reactions other than the ANAMMOX reaction. Particularly, a combination with denitrifying bacteria is preferable.
【００５２】本発明において、処理対象となる原水は、
アンモニア性窒素及び亜硝酸性窒素を含む水であり、有
機物及び有機性窒素を含むものであってもよいが、これ
らは脱窒処理前に予めアンモニア性窒素になる程度まで
分解しておくことが好ましく、また、溶存酸素濃度が高
い場合には、必要に応じて溶存酸素を除去しておくこと
が好ましい。原水は無機物を含んでいてもよい。また、
原水はアンモニア性窒素を含む液と亜硝酸性窒素を含む
液を混合したものであってもよい。例えば、アンモニア
性窒素を含む排水を硝化細菌の存在下に好気性処理を行
い、アンモニア性窒素の一部、好ましくはその４５〜７
０％、特に５０〜６０％を亜硝酸に部分酸化したものを
原水とすることができる。更には、アンモニア性窒素を
含む排水の一部を硝化細菌の存在下に好気性処理を行
い、アンモニア性窒素を亜硝酸に酸化し、アンモニア性
窒素を含む排水の残部と混合したものを原水としても良
い。In the present invention, the raw water to be treated is
Water containing ammoniacal nitrogen and nitrite nitrogen, which may contain organic matter and organic nitrogen, but these must be decomposed in advance to the extent of becoming ammoniacal nitrogen before denitrification treatment. Preferably, when the dissolved oxygen concentration is high, it is preferable to remove the dissolved oxygen as needed. Raw water may contain an inorganic substance. Also,
The raw water may be a mixture of a liquid containing ammoniacal nitrogen and a liquid containing nitrite nitrogen. For example, wastewater containing ammoniacal nitrogen is subjected to aerobic treatment in the presence of nitrifying bacteria, and a part of the ammoniacal nitrogen, preferably 45 to 7% thereof.
Raw water can be obtained by partially oxidizing 0%, particularly 50 to 60% of nitrous acid. Further, a part of the wastewater containing ammoniacal nitrogen is subjected to aerobic treatment in the presence of nitrifying bacteria, the ammoniacal nitrogen is oxidized to nitrite, and the mixture with the rest of the wastewater containing ammoniacal nitrogen is used as raw water. Is also good.
【００５３】一般的には、下水、し尿、汚泥消化脱離
液、その他工場排水、埋立浸出水等のアンモニア性窒
素、有機性窒素及び有機物を含む排水が処理対象となる
場合が多いが、この場合、これらを好気性又は嫌気性処
理して有機物を分解し、有機性窒素をアンモニア性窒素
に分解し、さらに部分亜硝酸化或いは、一部についての
亜硝酸化を行った液を原水とすることが好ましい。Generally, sewage, human waste, sludge digestion and desorption solution, other factory wastewater, landfill leachate, and other wastewater containing ammoniacal nitrogen, organic nitrogen and organic matter are often treated. In this case, these are subjected to aerobic or anaerobic treatment to decompose organic substances, decompose organic nitrogen into ammonia nitrogen, and further carry out partial nitration or a part of nitrite is used as raw water. It is preferable.
【００５４】[0054]
【実施例】以下に実験例及び実施例を挙げて本発明をよ
り具体的に説明する。EXAMPLES The present invention will be described more specifically with reference to experimental examples and examples.
【００５５】実験例１
図２に示す生物脱窒装置を用いて、アンモニア性窒素濃
度１００ｍｇ／Ｌ、亜硝酸性窒素濃度１４０ｍｇ／Ｌ、
重炭酸ナトリウム２００ｍｇ／Ｌ、及び微量のカルシウ
ムイオン、マグネシウムイオンその他の微量元素を含有
する合成排水を、窒素ガスで脱酸素した水を原水として
処理を行った。用いた生物脱窒装置の脱窒槽１の容積は
１Ｌ、沈殿槽３の容積は０．５Ｌで沈殿槽３の面積は５
０ｃｍ２である。Experimental Example 1 Using the biological denitrification apparatus shown in FIG. 2, ammoniacal nitrogen concentration 100 mg / L, nitrite nitrogen concentration 140 mg / L,
Synthetic wastewater containing 200 mg / L of sodium bicarbonate and a trace amount of calcium ions, magnesium ions, and other trace elements was treated with water deoxidized with nitrogen gas as raw water. The biological denitrification apparatus used had a denitrification tank 1 having a volume of 1 L, a sedimentation tank 3 having a volume of 0.5 L, and the sedimentation tank 3 having an area of 5 L.
It is 0 cm 2 .
【００５６】脱窒槽１と沈殿槽３は各々密閉し、上部の
気相部分を連通して、脱窒により発生した窒素ガスは系
外へ排出した。この排ガス排出管は、外気が逆流しない
ように水封した。The denitrification tank 1 and the precipitation tank 3 were hermetically sealed, the upper gas phase portion was connected, and the nitrogen gas generated by denitrification was discharged to the outside of the system. This exhaust gas discharge pipe was water-sealed so that the outside air would not flow backward.
【００５７】脱窒槽１内にはｐＨ計を設け、槽内液のｐ
Ｈが上昇したら炭酸ガスを導入することにより、槽内液
をｐＨ７．５に調整した。A pH meter is provided in the denitrification tank 1 so that the p
When H increased, carbon dioxide gas was introduced to adjust the pH of the liquid in the tank to 7.5.
【００５８】脱窒槽１内に、別の反応槽でフィル＆ドロ
ー方式で培養したＡＮＡＭＭＯＸ菌を主体とする汚泥を
１０００ｍｇ−ＶＳＳ／Ｌとなるように投入し、原水を
３Ｌ／ｄａｙの流量で通水した。また、沈殿槽３の分離
汚泥は２Ｌ／ｄａｙで脱窒槽１に返送した。In the denitrification tank 1, sludge mainly composed of ANAMMOX bacteria cultivated in a separate reaction tank by the fill-and-draw method was charged so as to be 1000 mg-VSS / L, and raw water was passed at a flow rate of 3 L / day. Watered The separated sludge in the settling tank 3 was returned to the denitrification tank 1 at 2 L / day.
【００５９】その結果、運転開始から２日以内に沈殿槽
３での汚泥の浮上が観察され、処理水中に汚泥が流出し
た。As a result, the sludge floated in the settling tank 3 was observed within 2 days after the start of the operation, and the sludge flowed out into the treated water.
【００６０】このときの沈殿槽３内液のアンモニア性窒
素濃度を測定したところ、汚泥が浮上し始めたときに７
ｍｇ／Ｌであり、その後急速に上昇して２０ｍｇ／Ｌと
なった。なお、亜硝酸性窒素濃度は、２５〜３５ｍｇ／
Ｌであった。When the ammonia nitrogen concentration of the liquid in the settling tank 3 at this time was measured, it was 7 when the sludge started to float.
mg / L, and then rapidly increased to 20 mg / L. The nitrite nitrogen concentration is 25-35 mg /
It was L.
【００６１】沈殿槽３での汚泥の浮上により、脱窒槽１
内の汚泥濃度が急速に低下したために、運転開始から３
回目に運転を停止したが、このときの脱窒槽１内の汚泥
濃度は８００ｍｇ−ＶＳＳ／Ｌに低下していた。As the sludge floats in the settling tank 3, the denitrification tank 1
Since the sludge concentration inside the tank decreased rapidly, 3
Although the operation was stopped for the second time, the sludge concentration in the denitrification tank 1 at this time was lowered to 800 mg-VSS / L.
【００６２】実験例２
実験例１の運転停止後、流出した汚泥を回収し、脱窒槽
１内の汚泥濃度が１００ｍｇ−ＶＳＳ／Ｌとなるように
脱窒槽１に投入し、原水を２Ｌ／ｄａｙの流量で通水し
て運転を再開した。Experimental Example 2 After the operation of Experimental Example 1 was stopped, the sludge that had flowed out was collected and put into the denitrification tank 1 so that the sludge concentration in the denitrification tank 1 was 100 mg-VSS / L, and the raw water was 2 L / day. Water was passed at the flow rate of and the operation was restarted.
【００６３】その結果、沈殿槽３内での汚泥の浮上を生
じることなく運転を行うことができた。このときの沈殿
槽３内液のアンモニア性窒素濃度は１ｍｇ／Ｌ以下であ
った。なお、亜硝酸性窒素濃度は１３０〜１３５ｍｇ／
Ｌであった。As a result, the operation could be performed without causing the sludge to float in the settling tank 3. At this time, the ammonia nitrogen concentration of the liquid in the precipitation tank 3 was 1 mg / L or less. The nitrite nitrogen concentration is 130-135 mg /
It was L.
【００６４】その後、脱窒槽１内の汚泥濃度の上昇に応
じて、原水の通水流量を徐々に増加させたところ、運転
開始から約２ヶ月後には脱窒槽内の汚泥濃度は２０００
ｍｇ−ＶＳＳ／Ｌにまで増加し、原水流量も４Ｌ／ｄａ
ｙまで増やすことができた。After that, when the flow rate of raw water was gradually increased in accordance with the increase in the sludge concentration in the denitrification tank 1, the sludge concentration in the denitrification tank was 2000 after about 2 months from the start of the operation.
Increased to mg-VSS / L and the raw water flow rate was also 4 L / da
I was able to increase to y.
【００６５】ただし、この間、数回、負荷（原水流入
量）が過剰となることにより、沈殿槽３内液のアンモニ
ア性窒素濃度が６〜１０ｍｇ／Ｌとなり、その都度汚泥
が浮上して流出する問題が生じた。この場合には、流出
した汚泥を回収して脱窒槽１に戻し、負荷を若干下げる
ことで対応した。However, during this time, the load (inflow of raw water) becomes excessive several times, so that the ammonia nitrogen concentration in the liquid in the settling tank 3 becomes 6 to 10 mg / L, and the sludge floats up and flows out each time. There was a problem. In this case, the sludge that had flowed out was collected and returned to the denitrification tank 1, and the load was slightly reduced.
【００６６】この結果、アンモニア性窒素の容積当たり
の負荷０．４ｋｇ−Ｎ／ｍ３／ｄａｙ、亜硝酸性窒素の
容積当たりの負荷０．５２ｋｇ−Ｎ／ｍ３／ｄａｙまで
負荷を高めることができた。なお、硝酸性窒素は０．１
ｋｇ−Ｎ／ｍ３／ｄａｙで増加したため、窒素の除去速
度は０．８２ｋｇ−Ｎ／ｍ３／ｄａｙとなった。沈殿槽
３の水面積負荷は０．８ｍ／ｄａｙであった。[0066] is possible to enhance the results, load 0.4kg-N / m 3 / day per volume of ammonium nitrogen load until the load 0.52kg-N / m 3 / day per volume of nitrite nitrogen did it. Nitrate nitrogen is 0.1
Since it increased at kg-N / m 3 / day, the removal rate of nitrogen was 0.82 kg-N / m 3 / day. The water area load of the settling tank 3 was 0.8 m / day.
【００６７】このときの沈殿槽３の汚泥のＳＶＩ（スラ
ッジ容積指数）を測定したところ、２０〜５０ｍＬ／ｇ
であり、比較的沈降性が良好なために沈殿槽３の水面積
負荷は活性汚泥と同程度で良いことを確認した。但し、
分散状態で浮遊し、上澄み側に残るフロックが存在する
ために、活性汚泥の場合よりもやや水面積負荷を低く取
ることが安全であると判断された。The SVI (sludge volume index) of the sludge in the settling tank 3 at this time was measured to be 20 to 50 mL / g.
It was confirmed that the water area load of the settling tank 3 is about the same as that of the activated sludge because the settling property is relatively good. However,
Since there are flocs that float in a dispersed state and remain on the supernatant side, it was judged safe to take a slightly lower water area load than in the case of activated sludge.
【００６８】実施例１
実験例２では、沈殿槽３における一応の汚泥浮上防止効
果が得られるが、負荷の管理が困難であり、負荷が過剰
になることでアンモニア性窒素の残留による汚泥の浮上
が起きた。Example 1 In Experimental Example 2, although a temporary sludge floating prevention effect in the settling tank 3 is obtained, it is difficult to manage the load, and the excess load causes sludge floating due to residual ammoniacal nitrogen. Happened.
【００６９】そこで、実験例１，２で用いた生物脱窒装
置の脱窒槽１と沈殿槽３との間に、図１に示す如く、容
積０．５Ｌの第２の脱窒槽２を直列に設けた生物脱窒装
置で原水の処理を行った。なお、沈殿槽３の分離汚泥は
第１の脱窒槽１に返送した。Therefore, as shown in FIG. 1, a second denitrification tank 2 having a volume of 0.5 L is connected in series between the denitrification tank 1 and the precipitation tank 3 of the biological denitrification apparatus used in Experimental Examples 1 and 2. Raw water was treated with the provided biological denitrification equipment. The separated sludge in the settling tank 3 was returned to the first denitrification tank 1.
【００７０】この生物脱窒装置では、第１の脱窒槽１で
原水のアンモニア性窒素の８０％以上が除去されている
ことを確認した後、５％負荷を上げ、その後第１の脱窒
槽１で負荷の８０％以上が除去されるまでＡＮＡＭＭＯ
Ｘ菌の増殖を行うことを繰り返して負荷を上げていった
ところ、沈殿槽３内液のアンモニア性窒素は常に１ｍｇ
／Ｌ以下に保つことができ、沈殿槽３での汚泥の浮上、
流出の問題は全く生じなかった。In this biological denitrification equipment, after confirming that 80% or more of the ammonia nitrogen in the raw water was removed in the first denitrification tank 1, the load was increased by 5%, and then the first denitrification tank 1 Until 80% or more of the load is removed by ANAMMO
When the load was increased by repeating the multiplication of X bacteria, the amount of ammonia nitrogen in the settling tank 3 was always 1 mg.
/ L or less, floating sludge in the settling tank 3,
There were no spill problems.
【００７１】第１の脱窒槽１と第２の脱窒槽２とでは同
じ汚泥濃度であるため、容積当たりのアンモニア性窒素
除去能力は同じである。従って、第１の脱窒槽１と第２
の脱窒槽２との合計のアンモニア性窒素除去能力に等し
い負荷をかけた場合には、第１の脱窒槽１の容積は、第
１の脱窒槽１と第２の脱窒槽２との合計の容積の６７％
であるから、第１の脱窒槽１におけるアンモニア性窒素
の除去率も全体の６７％となる。Since the first denitrification tank 1 and the second denitrification tank 2 have the same sludge concentration, they have the same ammonia nitrogen removal capacity per volume. Therefore, the first denitrification tank 1 and the second denitrification tank 1
When a load equal to the total ammonia nitrogen removal capacity with the denitrification tank 2 of No. 1 is applied, the volume of the first denitrification tank 1 is equal to the total volume of the first denitrification tank 1 and the second denitrification tank 2. 67% of volume
Therefore, the removal rate of ammoniacal nitrogen in the first denitrification tank 1 is 67% of the whole.
【００７２】しかし、本実施例では、ＡＮＡＭＭＯＸ菌
の増殖に応じて、ＡＮＡＭＭＯＸ菌のアンモニア性窒素
除去能力に余裕を残して負荷をかけるために、第１の脱
窒槽１におけるアンモニア性窒素の除去率を全体の７５
〜８０％に設定した。この場合、残りの２０〜２５％を
第２の脱窒槽２で除去するために必要な第２の容積は、
第１の脱窒槽と同じ汚泥濃度において、第１の脱窒槽２
の容積の２５〜３３％、即ち、２５０〜３３０ｍＬであ
る。However, in the present embodiment, the ammonia nitrogen removal rate in the first denitrification tank 1 is set so that the ammonia nitrogen removal capacity of the ANAMMOX bacteria is loaded with a margin in accordance with the growth of the ANAMMOX bacteria. The whole 75
It was set to -80%. In this case, the second volume required to remove the remaining 20 to 25% in the second denitrification tank 2 is
At the same sludge concentration as the first denitrification tank, the first denitrification tank 2
25-33% of the volume, i.e. 250-330 mL.
【００７３】しかし、本実施例では、第２の脱窒槽２の
容積を５００ｍＬとしたため、１７０〜２５０ｍＬの容
積分の余裕を確保することができ、アンモニア性窒素を
高度に除去することができたために、沈殿槽３内液のア
ンモニア性窒素濃度を１ｍｇ／Ｌ以下に安定させること
ができ、これにより、沈殿槽３内の汚泥の浮上、流出を
確実に防止することができた。However, in this embodiment, since the volume of the second denitrification tank 2 was set to 500 mL, it was possible to secure a margin for the volume of 170 to 250 mL and to highly remove ammonia nitrogen. In addition, the ammonia nitrogen concentration in the liquid in the settling tank 3 could be stabilized at 1 mg / L or less, and thus the floating and outflow of sludge in the settling tank 3 could be reliably prevented.
【００７４】実験例２のように、脱窒槽を１槽のみ設け
た場合には、流入負荷を管理することが困難であり、過
剰負荷によるアンモニア性窒素の残留、それによる汚泥
の浮上、流出を防止することができない場合があるが、
本実施例のように、脱窒槽を２槽直列に設けることで、
確実な負荷管理を行って、アンモニア性窒素濃度を安定
して低く抑え、沈殿槽における汚泥の浮上、流出を確実
に防止することができる。In the case where only one denitrification tank is provided as in Experimental Example 2, it is difficult to control the inflow load, and ammonia nitrogen remains due to excess load, and the sludge floats and flows out. It may not be possible to prevent it,
By providing two denitrification tanks in series as in this embodiment,
By performing reliable load management, the ammonia nitrogen concentration can be stably suppressed to a low level, and it is possible to reliably prevent floating and outflow of sludge in the settling tank.
【００７５】本実施例では、ＡＮＡＭＭＯＸ菌の増殖に
応じて、適宜負荷を増加することができ、また、汚泥の
流出の問題もないために、従来法に比べて汚泥の増殖速
度を２倍にすることができ、従来において、窒素除去能
力が２倍に上がるまでに約４０日を要していたのに対
し、その日数を約２０日に短縮することができた。そし
て、アンモニア性窒素の容積当たりの負荷０．８ｋｇ−
Ｎ／ｍ３／ｄａｙ、亜硝酸性窒素の容積当たりの負荷
１．０ｋｇ−Ｎ／ｍ３／ｄａｙまで処理可能であること
が確認された。なお、硝酸性窒素は０．２ｋｇ−Ｎ／ｍ
３／ｄａｙで増加したため、総合的な窒素の除去速度は
１．６ｋｇ−Ｎ／ｍ３／ｄａｙであった。In this example, the load can be appropriately increased according to the growth of the ANAMMOX bacteria, and since there is no problem of sludge outflow, the growth rate of sludge is doubled as compared with the conventional method. In the past, it took about 40 days until the nitrogen removal capacity doubled, whereas the number of days could be shortened to about 20 days. And the load per volume of ammonia nitrogen is 0.8 kg-
N / m 3 / day, it was confirmed that can be processed to the load 1.0kg-N / m 3 / day per volume of nitrite nitrogen. Nitrate nitrogen is 0.2 kg-N / m
The total removal rate of nitrogen was 1.6 kg-N / m 3 / day because it increased at 3 / day.
【００７６】以上の結果から明らかなように、本発明に
よれば、沈殿槽におけるＡＮＡＭＭＯＸ菌の浮上を効果
的に防止することができ、浮遊状態のＡＮＡＭＭＯＸ菌
を安定的に利用しつつ増殖させることが出来る。この結
果、脱窒槽の迅速な立ち上げが可能になり、脱窒槽内の
ＡＮＡＭＭＯＸ菌が持つ活性を有効に利用することがで
きる。また、ＡＮＡＭＭＯＸ菌の運搬を安価に行うこと
も可能である。As is clear from the above results, according to the present invention, it is possible to effectively prevent the flotation of ANAMMOX bacteria in the settling tank, and to grow the ANAMMOX bacteria in a suspended state while stably utilizing them. Can be done. As a result, the denitrification tank can be quickly started up, and the activity of the ANAMMOX bacteria in the denitrification tank can be effectively used. It is also possible to carry the ANAMMOX bacteria at low cost.
【００７７】また、２槽以上直列に脱窒槽を設けること
で、最大活性に対して現在かかっている負荷を把握し易
くなり、負荷の余裕分を容易に把握でき、常に適切な負
荷をかけることが可能となる。Further, by providing denitrification tanks in series with two or more tanks, it becomes easy to grasp the load that is currently applied to the maximum activity, the margin of the load can be easily grasped, and an appropriate load is always applied. Is possible.
【００７８】[0078]
【発明の効果】以上詳述した通り、本発明の生物脱窒方
法及び生物脱窒装置によれば、ＡＮＡＭＭＯＸ菌を懸濁
状態で増殖させて生物脱窒を行い、脱窒処理液からＡＮ
ＡＭＭＯＸ菌を沈殿分離する際に、沈殿槽におけるＡＮ
ＡＭＭＯＸ菌の浮上を防止し、系内にＡＮＡＭＭＯＸ菌
を高濃度に保持することにより高負荷で効率的な生物脱
窒を行うことができる。As described in detail above, according to the biological denitrification method and the biological denitrification apparatus of the present invention, ANAMMOX bacteria are grown in a suspended state to perform biological denitrification, and the AN is removed from the denitrification treatment liquid.
When the AMMOX bacteria are separated by precipitation, the AN in the precipitation tank is used.
By preventing the floating of AMMOX bacteria and keeping the ANAMMOX bacteria at a high concentration in the system, efficient biological denitrification can be performed under a high load.
【００７９】特に、請求項４の生物脱窒方法及び請求項
６の生物脱窒装置によれば、沈殿槽からの返送汚泥が原
水により希釈されるのを防止して、前段の脱窒槽に高濃
度でＡＮＡＭＭＯＸ菌を保持してより一層高負荷の生物
脱窒処理を行うことが可能となる。In particular, according to the biological denitrification method of claim 4 and the biological denitrification apparatus of claim 6, it is possible to prevent the sludge returned from the settling tank from being diluted with the raw water, so that the denitrification tank of the preceding stage can be highly protected. It becomes possible to carry out an even higher load of biological denitrification by holding the ANAMMOX bacteria at a concentration.
【図１】本発明の生物脱窒方法及び生物脱窒装置の実施
の形態を示す系統図である。FIG. 1 is a system diagram showing an embodiment of a biological denitrification method and a biological denitrification apparatus of the present invention.
【図２】本発明の生物脱窒方法の他の実施の形態を示す
系統図である。FIG. 2 is a system diagram showing another embodiment of the biological denitrification method of the present invention.
１ 第１の脱窒槽（脱窒槽） ２ 第２の脱窒槽 ３ 沈殿槽 1 First denitrification tank (denitrification tank) 2 Second denitrification tank 3 settling tank
─────────────────────────────────────────────────────
─────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成１３年７月２６日（２００１．７．２
６）[Submission date] July 26, 2001 (2001.7.2)
6)
【手続補正１】[Procedure Amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００６３[Correction target item name] 0063
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【００６３】その結果、沈殿槽３内での汚泥の浮上を生
じることなく運転を行うことができた。このときの沈殿
槽３内液のアンモニア性窒素濃度は１ｍｇ／Ｌ以下であ
った。なお、亜硝酸性窒素濃度は５〜１０ｍｇ／Ｌであ
った。As a result, the operation could be performed without causing the sludge to float in the settling tank 3. At this time, the ammonia nitrogen concentration of the liquid in the precipitation tank 3 was 1 mg / L or less. The nitrite nitrogen concentration was 5 to 10 mg / L.
Claims (6)
ンモニア性窒素を電子供与体とし、亜硝酸性窒素を電子
受容体とする脱窒微生物の作用により亜硝酸性窒素の存
在下に生物脱窒する脱窒工程と、 脱窒工程の処理液を固液分離し、分離液を処理水として
排出する固液分離工程と、を有する生物脱窒方法におい
て、 固液分離する脱窒工程の処理液中のアンモニア性窒素濃
度と亜硝酸性窒素濃度の両方又はいずれか一方を０〜５
ｍｇ／Ｌとすることを特徴とする生物脱窒方法。1. Biodenitrification of raw water containing ammoniacal nitrogen in the presence of nitrite nitrogen by the action of a denitrifying microorganism using ammoniacal nitrogen as an electron donor and nitrite nitrogen as an electron acceptor. In the biological denitrification method including a denitrification step of performing solid-liquid separation of the denitrification process and a solid-liquid separation step of discharging the separated liquid as treated water, the treatment liquid of the denitrification step of solid-liquid separation Either or both of the ammonia nitrogen concentration and the nitrite nitrogen concentration in 0 to 5
A biological denitrification method characterized in that the amount is mg / L.
ンモニア性窒素を電子供与体とし、亜硝酸性窒素を電子
受容体とする脱窒微生物の作用により亜硝酸性窒素の存
在下に生物脱窒する脱窒槽に導入して脱窒処理し、該脱
窒槽の流出液を沈殿槽に導入して固液分離し、分離液を
処理水として排出すると共に分離汚泥を前記脱窒槽に返
送する生物脱窒方法において、 脱窒槽を複数直列に設け、最後段の脱窒槽の流出液を該
沈殿槽に導入することを特徴とする生物脱窒方法。2. Biodenitrification of raw water containing ammoniacal nitrogen in the presence of nitrite nitrogen by the action of a denitrifying microorganism using ammoniacal nitrogen as an electron donor and nitrite nitrogen as an electron acceptor. The effluent of the denitrification tank is introduced into the sedimentation tank for solid-liquid separation, the separated liquid is discharged as treated water, and the separated sludge is returned to the denitrification tank. In the nitrification method, a plurality of denitrification tanks are provided in series, and the effluent of the final denitrification tank is introduced into the settling tank.
液中のアンモニア性窒素濃度と亜硝酸性窒素濃度の両方
又はいずれか一方を０〜５ｍｇ／Ｌとすることを特徴と
する請求項２に記載の生物脱窒方法。3. The concentration of ammonia nitrogen and / or nitrite nitrogen in the effluent of the final denitrification tank introduced into the precipitation tank is set to 0 to 5 mg / L. Item 2. The biological denitrification method according to Item 2.
割注入することを特徴とする請求項２又は３に記載の生
物脱窒方法。4. The biological denitrification method according to claim 2, wherein the raw water is dividedly injected into a plurality of denitrification tanks provided in series.
口と処理液の流出口を有し、アンモニア性窒素を電子供
与体とし、亜硝酸性窒素を電子受容体とする脱窒微生物
の作用により亜硝酸性窒素の存在下に原水を生物脱窒す
る複数の脱窒槽と、 該脱窒槽の処理液を固液分離する沈殿槽と、 該沈殿槽で分離された分離液を処理水として排出する手
段と、 該沈殿槽で分離された分離汚泥を前記第１の脱窒槽へ返
送する手段とを備えてなり、 前記複数の脱窒槽は、前段側の脱窒槽の処理水が後段側
の脱窒槽に導入されて脱窒処理されるように直列に接続
されており、 最終段の脱窒槽の処理液が前記沈殿槽に導入されること
を特徴とする生物脱窒装置。5. A denitrifying microorganism having an inlet for raw water containing ammonia nitrogen and an outlet for a treatment solution, wherein ammonia nitrogen is used as an electron donor and nitrite nitrogen is used as an electron acceptor. A plurality of denitrification tanks for biologically denitrifying raw water in the presence of nitrite nitrogen, a settling tank for solid-liquid separation of the treatment liquid in the denitrification tank, and the separated liquid separated in the settling tank is discharged as treated water. And a means for returning the separated sludge separated in the settling tank to the first denitrification tank, wherein the plurality of denitrification tanks are the denitrification tank in which the treated water in the denitrification tank in the front side is in the rear side. A biological denitrification apparatus, which is connected in series so as to be introduced into the denitrification process and is introduced into the precipitation tank of the treatment liquid in the final denitrification tank.
を備えたことを特徴とする請求項５に記載の生物脱窒装
置。6. The biological denitrification apparatus according to claim 5, further comprising means for separately injecting raw water into a plurality of denitrification tanks.
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2003033789A (en) * | 2001-07-26 | 2003-02-04 | Kurita Water Ind Ltd | Method for denitrificaton treatment using living organisms and device therefor |
| JP2003039093A (en) * | 2001-07-31 | 2003-02-12 | Kurita Water Ind Ltd | Denitrification method and denitrification apparatus |
| JP2004230225A (en) * | 2003-01-28 | 2004-08-19 | Kurita Water Ind Ltd | Method for treating ammonia-containing water |
| JP2007244932A (en) * | 2006-03-13 | 2007-09-27 | Hitachi Plant Technologies Ltd | Nitrogen elimination process and wastewater treatment method |
| CN103121752A (en) * | 2013-01-05 | 2013-05-29 | 北京工业大学 | Method for processing urban sewage nitrifying liquid by sludge fermentation and denitrification coupled with anaerobic ammonia oxidation |
| CN105481210A (en) * | 2016-02-26 | 2016-04-13 | 北京化工大学 | Combined sewage denitrification process and device having automatic cyclic flowing function |
| KR20190036658A (en) * | 2017-09-28 | 2019-04-05 | 홍원방 | Wastewater nitrogen treatment system using denitrification tower |
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|---|---|---|---|---|
| JP2001104992A (en) * | 1999-10-12 | 2001-04-17 | Kurita Water Ind Ltd | Method and apparatus for bilogically removing nitrogen |
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2001
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001104992A (en) * | 1999-10-12 | 2001-04-17 | Kurita Water Ind Ltd | Method and apparatus for bilogically removing nitrogen |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003033789A (en) * | 2001-07-26 | 2003-02-04 | Kurita Water Ind Ltd | Method for denitrificaton treatment using living organisms and device therefor |
| JP2003039093A (en) * | 2001-07-31 | 2003-02-12 | Kurita Water Ind Ltd | Denitrification method and denitrification apparatus |
| JP2004230225A (en) * | 2003-01-28 | 2004-08-19 | Kurita Water Ind Ltd | Method for treating ammonia-containing water |
| JP4613474B2 (en) * | 2003-01-28 | 2011-01-19 | 栗田工業株式会社 | Method for treating ammonia-containing water |
| JP2007244932A (en) * | 2006-03-13 | 2007-09-27 | Hitachi Plant Technologies Ltd | Nitrogen elimination process and wastewater treatment method |
| CN103121752A (en) * | 2013-01-05 | 2013-05-29 | 北京工业大学 | Method for processing urban sewage nitrifying liquid by sludge fermentation and denitrification coupled with anaerobic ammonia oxidation |
| CN105481210A (en) * | 2016-02-26 | 2016-04-13 | 北京化工大学 | Combined sewage denitrification process and device having automatic cyclic flowing function |
| KR20190036658A (en) * | 2017-09-28 | 2019-04-05 | 홍원방 | Wastewater nitrogen treatment system using denitrification tower |
| KR102097471B1 (en) * | 2017-09-28 | 2020-04-06 | 홍원방 | Wastewater nitrogen treatment system using denitrification tower |
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