JP2003053382A - Nitrification-denitrification treatment method - Google Patents
Nitrification-denitrification treatment methodInfo
- Publication number
- JP2003053382A JP2003053382A JP2001242451A JP2001242451A JP2003053382A JP 2003053382 A JP2003053382 A JP 2003053382A JP 2001242451 A JP2001242451 A JP 2001242451A JP 2001242451 A JP2001242451 A JP 2001242451A JP 2003053382 A JP2003053382 A JP 2003053382A
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- Japan
- Prior art keywords
- nitrification
- nitrogen
- nitrite
- cod
- denitrification
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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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
及びＣＯＤ成分を含む原水をアンモニア酸化細菌により
硝化した後脱窒する方法に係り、特に、硝化工程におい
て亜硝酸酸化細菌とＣＯＤ分解細菌を抑制して亜硝酸型
硝化を行った後、脱窒工程において、残留するＣＯＤを
電子供与体として亜硝酸性窒素を脱窒細菌により効率的
に脱窒する硝化脱窒処理方法に関する。TECHNICAL FIELD The present invention relates to a method for denitrifying raw water containing ammoniacal nitrogen and COD components after nitrification with ammonia-oxidizing bacteria, and particularly to suppressing nitrite-oxidizing bacteria and COD-degrading bacteria in the nitrification process. The present invention relates to a nitrification / denitrification treatment method of efficiently denitrifying nitrite nitrogen by denitrifying bacteria using COD remaining as an electron donor in the denitrification step after performing nitrite-type nitrification.
【０００２】[0002]
【従来の技術】排水中に含まれるアンモニア性窒素は河
川、湖沼及び海洋などにおける富栄養化の原因物質の一
つであり、排水処理工程で効率的に除去する必要があ
る。一般に、排水中のアンモニア性窒素は、アンモニア
性窒素をアンモニア酸化細菌により亜硝酸性窒素に酸化
し、更にこの亜硝酸性窒素を亜硝酸酸化細菌により硝酸
性窒素に酸化する硝化工程と、生成した硝酸性窒素を従
属栄養性細菌である脱窒菌により窒素ガスにまで分解す
る脱窒工程との２段階の生物反応を経て窒素ガスにまで
分解される。2. Description of the Related Art Ammoniacal nitrogen contained in wastewater is one of the causative substances of eutrophication in rivers, lakes and oceans, and it is necessary to efficiently remove it in the wastewater treatment process. In general, ammoniacal nitrogen in wastewater is generated by a nitrification process in which ammoniacal nitrogen is oxidized to nitrite nitrogen by ammonia-oxidizing bacteria, and the nitrite nitrogen is further oxidized to nitrate nitrogen by nitrite-oxidizing bacteria. The nitrogen is decomposed into nitrogen gas through a two-step biological reaction with a denitrification process of decomposing nitrate nitrogen into nitrogen gas by a denitrifying bacterium which is a heterotrophic bacterium.
【０００３】硝化工程において、アンモニア性窒素を酸
化するためには、多量の酸素を供給する必要があり、曝
気コストが高くつく。また、従来の硝化脱窒法では、曝
気のためのコストのみならず、脱窒工程において電子供
与体としてメタノールなどの炭素源を多量に必要とす
る。In the nitrification process, in order to oxidize ammoniacal nitrogen, it is necessary to supply a large amount of oxygen, and the aeration cost is high. Further, in the conventional nitrification denitrification method, not only the cost for aeration but also a large amount of a carbon source such as methanol as an electron donor is required in the denitrification step.
【０００４】排水中にＣＯＤ成分が含有されている場
合、このＣＯＤ成分を脱窒工程における炭素源として利
用することも考えられるが、好気性条件の硝化工程にお
いては、ＣＯＤ分解細菌も活発に活動するため、排水中
のＣＯＤ成分は硝化工程でＣＯ ２まで酸化分解される。
このため、後段の脱窒工程において、新たに必要な炭素
源を添加する必要がある。When the COD component is contained in the waste water
When this COD component is used as a carbon source in the denitrification process,
Although it can be used for nitrification process under aerobic conditions,
In addition, COD-degrading bacteria are also active in the wastewater.
COD component of CO in the nitrification process TwoOxidatively decomposes to
Therefore, in the denitrification process in the latter stage, newly required carbon
The source needs to be added.
【０００５】このようなことから、従来の硝化脱窒処理
では、硝化工程における曝気動力と脱窒工程における炭
素源の添加コストが運転コストのうちの大部分を占めて
いる。From the above, in the conventional nitrification and denitrification treatment, the aeration power in the nitrification step and the carbon source addition cost in the denitrification step occupy most of the operating cost.
【０００６】特に高濃度にアンモニア性窒素を含有する
排水を処理する場合には、アンモニア性窒素を硝酸性窒
素にまで酸化するために大量の酸素を必要とすることか
ら、曝気コストが高騰し、また、硝酸性窒素を窒素ガス
にまで脱窒する反応を行うために、メタノール等の炭素
源を大量に供給する必要があり、運転コストが高いもの
となっていた。Particularly when treating wastewater containing ammoniacal nitrogen at a high concentration, a large amount of oxygen is required to oxidize the ammoniacal nitrogen to nitrate nitrogen, so the aeration cost rises. Further, in order to carry out the reaction of denitrifying nitrate nitrogen into nitrogen gas, it is necessary to supply a large amount of carbon source such as methanol, resulting in high operating cost.
【０００７】硝化工程における曝気コストを低減する方
法として、アンモニア性窒素の酸化を亜硝酸性窒素で止
め、硝酸性窒素を生成させない亜硝酸型硝化を行い、亜
硝酸性窒素を脱窒する方法がある。As a method for reducing the aeration cost in the nitrification process, there is a method of denitrifying nitrite nitrogen by stopping the oxidation of ammonia nitrogen with nitrite nitrogen and performing nitrite type nitrification without producing nitrate nitrogen. is there.
【０００８】この場合には、下記反応式からも明らかな
ように、アンモニア性窒素の酸化に必要な酸素量は２５
％低減することができ、また、脱窒に必要な炭素源も４
０％低減することができる。
ＮＨ４ ＋＋３／２Ｏ２→ＮＯ２＋Ｈ２Ｏ＋２Ｈ＋
ＮＯ２ −＋１／２Ｏ２→ＮＯ３ −
ＮＯ３＋ＣＯＤ→Ｎ２ In this case, as is clear from the following reaction formula, the amount of oxygen required for the oxidation of ammoniacal nitrogen is 25.
%, And the carbon source required for denitrification is 4%
It can be reduced by 0%. NH 4 + + 3 / 2O 2 → NO 2 + H 2 O + 2H + NO 2 - + 1 / 2O 2 → NO 3 - NO 3 + COD → N 2
【０００９】従来、亜硝酸型硝化を行う方法としては、
アンモニア性窒素を硝化槽内に残留させ、アンモニ
ア性窒素による亜硝酸酸化細菌の阻害を利用する方法
硝化槽内の溶存酸素（ＤＯ）量を低く抑える方法
高温でのアンモニア酸化細菌と亜硝酸酸化細菌との
増殖速度の差を利用した方法（ＳＨＡＲＯＮプロセス）
などが提案されている。Conventionally, as a method of performing nitrite type nitrification, a method of leaving ammonia nitrogen in the nitrification tank and utilizing inhibition of nitrite-oxidizing bacteria by the ammonia nitrogen, dissolved oxygen (DO) amount in the nitrification tank Method to control low temperature Method utilizing difference in growth rate between ammonia-oxidizing bacteria and nitrite-oxidizing bacteria at high temperature (SHARON process)
Have been proposed.
【００１０】[0010]
【発明が解決しようとする課題】しかし、このうち、ア
ンモニア性窒素による阻害を利用する方法は、硝化処理
液中にアンモニア性窒素が残留することとなるため適当
ではない。また、ＳＨＡＲＯＮプロセスは、ケモスタッ
ト処理であるため、汚泥濃度を高くすることができず、
このために硝化槽が大型化するという欠点がある。亜硝
酸型硝化を行うためにはＤＯを低く抑えることが有効で
あると考えられるが、ＤＯを低く抑えると硝化に必要な
ＤＯが不足する恐れがある。However, among these methods, the method of utilizing inhibition by ammoniacal nitrogen is not suitable because the ammoniacal nitrogen remains in the nitrification treatment solution. Moreover, since the SHARON process is a chemostat process, it is not possible to increase the sludge concentration,
Therefore, there is a drawback that the nitrification tank becomes large. It is considered effective to suppress DO to be low in order to carry out nitrite type nitrification, but if DO is suppressed to be low, DO required for nitrification may be insufficient.
【００１１】このようなことから、従来において、亜硝
酸型硝化を安定に維持し得る制御方法が提供されておら
ず、このことが亜硝酸型硝化の実用化を阻む原因となっ
ていた。From the above, a control method capable of stably maintaining the nitrite type nitrification has not been provided so far, which has been a cause of impeding the practical use of the nitrite type nitrification.
【００１２】また、前述の如く、硝化工程におけるＣＯ
Ｄ成分の分解を抑制することにより、原水中のＣＯＤ成
分を脱窒工程における電子供与体として利用することで
脱窒工程の炭素源の供給量の低減を図ることが考えられ
る。Further, as described above, CO in the nitrification process
By suppressing the decomposition of the D component, it is considered that the COD component in the raw water is used as an electron donor in the denitrification process to reduce the supply amount of the carbon source in the denitrification process.
【００１３】従って、ＣＯＤ成分の分解を抑制した上
で、安定な亜硝酸型硝化を行う方法が望まれる。Therefore, it is desired to provide a method for carrying out stable nitrite type nitrification while suppressing the decomposition of COD components.
【００１４】本発明は上記従来の実情に鑑みてなされた
ものであって、アンモニア性窒素とＣＯＤ成分を含む原
水を硝化脱窒処理するに当たり、硝化工程においてＣＯ
Ｄ成分の分解を抑制した上で亜硝酸型硝化を安定に行う
ことにより、硝化工程での曝気コストの低減と、脱窒工
程での炭素源添加コストの低減を図る硝化脱窒処理方法
を提供することを目的とする。The present invention has been made in view of the above-mentioned conventional circumstances, and when raw water containing ammoniacal nitrogen and COD components is subjected to nitrification / denitrification treatment, CO
Providing a nitrification denitrification treatment method that reduces the aeration cost in the nitrification process and the carbon source addition cost in the denitrification process by stabilizing the nitrite type nitrification while suppressing the decomposition of the D component The purpose is to do.
【００１５】[0015]
【課題を解決するための手段】本発明の硝化脱窒処理方
法は、アンモニア性窒素及びＣＯＤ成分を含む原水を硝
化脱窒処理する方法において、原水中の溶存酸素を低濃
度に保持しながら、アンモニア酸化細菌の存在下に亜硝
酸型硝化反応を行うと共に蓄積した亜硝酸性窒素の濃度
阻害によりＣＯＤ分解細菌を抑制する硝化工程と、該硝
化工程で生成した亜硝酸性窒素を、残留するＣＯＤ成分
を電子供与体として脱窒細菌の作用により脱窒する脱窒
工程とを有することを特徴とする。Means for Solving the Problems The nitrification denitrification treatment method of the present invention is a method for nitrifying denitrification treatment of raw water containing ammoniacal nitrogen and COD components, while maintaining a low concentration of dissolved oxygen in the raw water, A nitrification step of performing a nitrite-type nitrification reaction in the presence of ammonia-oxidizing bacteria and suppressing COD-degrading bacteria by inhibiting the concentration of accumulated nitrite nitrogen, and a COD remaining in the nitrification nitrogen produced in the nitrification step And a denitrification step of denitrifying the component as an electron donor by the action of denitrifying bacteria.
【００１６】脱窒細菌は、通性嫌気性菌で、ＤＯが存在
しない場合は硝酸性窒素ないし亜硝酸性窒素の結合酸素
を利用してＣＯＤ成分（有機物）を酸化分解するが、Ｄ
Ｏが存在する場合には、ＤＯを利用してＣＯＤ成分を酸
化分解する。このため、硝化工程においてＤＯ濃度が高
いとＣＯＤ分解細菌によりＣＯＤ成分が分解されてしま
う。The denitrifying bacterium is a facultative anaerobic bacterium, and when DO is not present, it oxidatively decomposes COD components (organic substances) by utilizing the bound oxygen of nitrate nitrogen or nitrite nitrogen.
When O is present, DO is used to oxidatively decompose the COD component. Therefore, if the DO concentration is high in the nitrification step, the COD components will be decomposed by the COD-decomposing bacteria.
【００１７】一方、亜硝酸化合物は食品添加物としても
使用されており微生物の活動を抑える作用を有する。On the other hand, the nitrite compound is also used as a food additive and has the action of suppressing the activity of microorganisms.
【００１８】本発明では、硝化工程においてＤＯ濃度を
低く維持して亜硝酸型硝化を行うと共に亜硝酸性窒素を
高濃度に蓄積させ、低濃度ＤＯと高濃度亜硝酸性窒素条
件下において、ＣＯＤ分解細菌の活動を抑制し、原水中
のＣＯＤ成分を殆ど分解することなく脱窒工程に送給す
る。また、このような低濃度ＤＯ及び高濃度亜硝酸性窒
素条件は亜硝酸型硝化の安定化にも有効である。In the present invention, the nitrite type nitrification is carried out while keeping the DO concentration low in the nitrification step, and the nitrite nitrogen is accumulated at a high concentration, and COD is obtained under the conditions of low DO and high nitrite nitrogen. It suppresses the activity of degrading bacteria and sends COD components in raw water to the denitrification process with almost no decomposition. Further, such low concentration DO and high concentration nitrite nitrogen conditions are also effective for stabilizing nitrite type nitrification.
【００１９】このため、脱窒工程においては、残留した
ＣＯＤ成分を電子供与体として利用して硝化により生成
した亜硝酸性窒素を脱窒処理することができる。Therefore, in the denitrification step, the residual COD component can be used as an electron donor to denitrify the nitrite nitrogen produced by nitrification.
【００２０】本発明では、硝化工程において、亜硝酸型
硝化を行うことにより曝気コストを低減すると共に、脱
窒工程における炭素源の必要量を低減することができ
る。しかも、硝化工程においてＣＯＤ成分の分解を抑制
してこれを脱窒工程に導入することで、原水中のＣＯＤ
成分を脱窒工程の炭素源として利用することができ、脱
窒工程において、炭素源の供給量をより一層低減するか
或いは全く不要とすることができる。In the present invention, by performing nitrite type nitrification in the nitrification step, the aeration cost can be reduced and the required amount of carbon source in the denitrification step can be reduced. Moreover, by suppressing the decomposition of the COD component in the nitrification process and introducing it into the denitrification process, COD in the raw water is reduced.
The component can be used as a carbon source in the denitrification process, and the supply amount of the carbon source can be further reduced or eliminated altogether in the denitrification process.
【００２１】[0021]
【発明の実施の形態】以下に本発明の硝化脱窒処理方法
の実施の形態を詳細に説明する。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the nitrification denitrification treatment method of the present invention will be described in detail below.
【００２２】図１は本発明の硝化脱窒処理方法の実施の
形態を示す系統図である。FIG. 1 is a system diagram showing an embodiment of the nitrification denitrification treatment method of the present invention.
【００２３】本発明においては、亜硝酸性窒素とＣＯＤ
成分を含む原水を、まず硝化槽１に導入して曝気下アン
モニア酸化細菌によりアンモニア性窒素を亜硝酸性窒素
に酸化する。In the present invention, nitrite nitrogen and COD
Raw water containing the components is first introduced into the nitrification tank 1, and ammonia nitrogen is oxidized to nitrite nitrogen by ammonia-oxidizing bacteria under aeration.
【００２４】この硝化槽１においては、亜硝酸型硝化を
行うと共にＣＯＤ分解細菌の活動を抑制してＣＯＤ成分
の分解を防止するために、低ＤＯ濃度かつ高濃度亜硝酸
性窒素条件下で硝化を行う。In this nitrification tank 1, in order to carry out nitrite type nitrification and suppress the activity of COD-degrading bacteria to prevent the decomposition of COD components, nitrification under low DO concentration and high concentration nitrite nitrogen conditions is carried out. I do.
【００２５】この硝化条件は、ＤＯ濃度として０．１〜
０．３ｍｇ／Ｌ、亜硝酸性窒素濃度として５０ｍｇ−Ｎ
／Ｌ以上であることが好ましい。ＤＯ濃度が上記範囲よ
りも高いと亜硝酸性窒素が更に酸化された硝酸性窒素が
生成する恐れがあり、また、ＣＯＤ分解細菌の活動が活
発になりＣＯＤ成分の分解が進行する。ＤＯ濃度が上記
範囲よりも低いと硝化反応のための酸素が不足してアン
モニア性窒素の酸化が進行しにくくなる。また、亜硝酸
性窒素濃度が上記範囲よりも低いとＣＯＤ分解細菌の活
動を十分に抑制し得ずＣＯＤ成分の分解が進行し、ま
た、硝化反応が亜硝酸型硝化とならず、硝酸性窒素が生
成する。従って、硝化槽１においては上記ＤＯ濃度条件
となるように曝気量を抑制すると共に、亜硝酸性窒素濃
度が上記濃度以上となるように、必要に応じて処理開始
時に硝化槽１に亜硝酸性窒素を添加する。この亜硝酸性
窒素としては、薬品としての亜硝酸や亜硝酸ナトリウム
等の亜硝酸塩であっても良く、また、アンモニアを含む
排水を亜硝酸型硝化により亜硝酸性窒素を生成させたも
のであっても良く、他系統の亜硝酸性窒素含有排水であ
っても良い。This nitrification condition is 0.1 to 0.1 in terms of DO concentration.
0.3 mg / L, as nitrite nitrogen concentration 50 mg-N
/ L or more is preferable. If the DO concentration is higher than the above range, nitrate nitrogen, which is further oxidized nitrite nitrogen, may be produced, and the activity of COD-degrading bacteria becomes active, and the decomposition of COD components proceeds. When the DO concentration is lower than the above range, oxygen for nitrification reaction is insufficient and it becomes difficult for the oxidation of ammoniacal nitrogen to proceed. When the concentration of nitrite nitrogen is lower than the above range, the activity of COD-degrading bacteria cannot be sufficiently suppressed, the decomposition of COD components proceeds, and the nitrification reaction does not result in nitrite-type nitrification. Is generated. Therefore, in the nitrification tank 1, the amount of aeration is suppressed so that the DO concentration condition is satisfied, and the nitrite nitrogen concentration in the nitrification tank 1 is increased as necessary at the start of the treatment so that the nitrite nitrogen concentration is equal to or higher than the above concentration. Add nitrogen. The nitrite nitrogen may be nitrite such as nitrous acid or sodium nitrite as a chemical, and nitrite nitrogen is produced by nitrite type nitrification of wastewater containing ammonia. Alternatively, the nitrite nitrogen-containing waste water of another system may be used.
【００２６】なお、亜硝酸性窒素濃度の上限については
特に制限はないが、通常の場合、２０００ｍｇ／Ｌ程度
である。The upper limit of the nitrite nitrogen concentration is not particularly limited, but it is usually about 2000 mg / L.
【００２７】硝化槽１では、上記条件において、原水中
に含有されるアンモニア性窒素の９０％以上を亜硝酸性
窒素に転換すると共に、ＣＯＤ成分の８０％以上を分解
せずに残留させることが好ましい。In the nitrification tank 1, under the above conditions, 90% or more of the ammoniacal nitrogen contained in the raw water can be converted to nitrite nitrogen, and 80% or more of the COD component can be left without being decomposed. preferable.
【００２８】硝化槽１のその他の条件としては、ｐＨ
７．０〜８．０、温度２５〜３５℃であることが安定し
た亜硝酸型硝化のために好ましい。Other conditions for the nitrification tank 1 include pH.
A temperature of 7.0 to 8.0 and a temperature of 25 to 35 ° C. are preferable for stable nitrite type nitrification.
【００２９】硝化槽１の処理水は次いで脱窒槽２に送給
し、嫌気条件にて脱窒菌の作用により、残留するＣＯＤ
成分を電子供与体として硝化反応で生成した亜硝酸性窒
素を窒素ガスに脱窒する。The treated water in the nitrification tank 1 is then fed to the denitrification tank 2, and COD remaining under the anaerobic condition by the action of denitrifying bacteria.
The nitrite nitrogen produced by the nitrification reaction is denitrified into nitrogen gas by using the component as an electron donor.
【００３０】この脱窒処理に当たり、硝化槽１の処理水
中に残留するＣＯＤ成分のみでは、電子供与体量が不足
する場合には、別途メタノール等の有機物を脱窒槽２に
添加して不足分を補う。In this denitrification treatment, when the amount of the electron donor is insufficient with only the COD component remaining in the treated water of the nitrification tank 1, an organic substance such as methanol is separately added to the denitrification tank 2 to make up the shortage. compensate.
【００３１】この脱窒槽２では、脱窒処理により亜硝酸
性窒素が除去されると共に、ＣＯＤ成分が脱窒処理に使
用されることで、ＣＯＤ成分の除去も行われる。In the denitrification tank 2, the nitrite nitrogen is removed by the denitrification process, and the COD component is also used for the denitrification process to remove the COD component.
【００３２】脱窒槽２の処理水は、必要に応じて、再曝
気槽３に送給して好気条件下処理することにより、残留
するＣＯＤ成分を分解除去した後、沈殿槽４で固液分離
し、分離液を処理水として取り出す。一方、分離汚泥は
必要に応じて一部を余剰汚泥として系外に排出し、残部
を硝化槽１に返送する。なお、再曝気槽３は必ずしも必
要とされず、脱窒処理後に残留するＣＯＤ成分が少ない
場合には、再曝気槽３は省略しても良い。The treated water in the denitrification tank 2 is, if necessary, fed to the re-aeration tank 3 and treated under aerobic conditions to decompose and remove the remaining COD components, and then solid-liquid in the precipitation tank 4. Separate and take out the separated liquid as treated water. On the other hand, a part of the separated sludge is discharged outside the system as a surplus sludge as necessary, and the rest is returned to the nitrification tank 1. The re-aeration tank 3 is not always necessary, and the re-aeration tank 3 may be omitted when the COD component remaining after the denitrification process is small.
【００３３】なお、硝化槽や脱窒槽の型式には特に制限
はなく、汚泥懸濁式の他、固定床、流動床、グラニュー
ル法、担体添加法等の生物膜式等を採用することがで
き、このような反応槽であれば、後段の沈殿槽を省略す
ることができる。また、曝気装置の近傍では溶存酸素濃
度が局所的に高くなり、亜硝酸酸化細菌やＣＯＤ分解細
菌の活動が活発になるため、活性汚泥のような分散型の
増殖においてはＤＯを制御するためには槽内の分布も考
慮に入れた細かな制御が必要なるが、生物膜を利用した
方法では膜内では酸素の浸透が少ないので、より効果的
にＤＯを下げることができる。There are no particular restrictions on the type of nitrification tank or denitrification tank, and in addition to sludge suspension type, fixed bed, fluidized bed, biofilm type such as granulation method, carrier addition method, etc. may be adopted. With such a reaction tank, the subsequent precipitation tank can be omitted. In addition, the dissolved oxygen concentration locally increases near the aeration device, and the activity of nitrite-oxidizing bacteria and COD-decomposing bacteria becomes active. Therefore, in order to control DO in the dispersed type growth such as activated sludge. Requires a fine control in consideration of the distribution in the tank, but the method using a biofilm can reduce the DO more effectively because the oxygen permeation in the film is small.
【００３４】本発明の方法は、亜硝酸型硝化を行うと共
に、原水中のＣＯＤ成分を脱窒反応の電子供与体として
利用することにより曝気コスト及び炭素源の添加コスト
を低減するものであり、一般的にはＣＯＤ成分を５０ｍ
ｇ／Ｌ以上、特に５００〜１０００ｍｇ／Ｌ、アンモニ
ア性窒素を２００〜５００ｍｇ／Ｌ程度含む原水、例え
ば、食品工場排水等の排水処理に有効である。The method of the present invention reduces the aeration cost and the carbon source addition cost by utilizing the COD component in the raw water as an electron donor for the denitrification reaction while performing the nitrite type nitrification. Generally, COD component is 50m
It is effective for treating raw water containing g / L or more, particularly 500 to 1000 mg / L, and ammoniacal nitrogen of about 200 to 500 mg / L, for example, waste water such as food factory waste water.
【００３５】[0035]
【実施例】以下に実施例及び比較例を挙げて本発明をよ
り具体的に説明する。EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples below.
【００３６】実施例１
ペプトン、酵母エキスを主体とした合成排水に（Ｎ
Ｈ４）２ＳＯ４を添加し、ＣＯＤ濃度を１０００ｍｇ／
Ｌ、アンモニア性窒素濃度を５００ｍｇ／Ｌに調整した
ものを原水として、本発明に従って硝化脱窒処理を行っ
た。汚泥は硝化脱窒処理を行っている下水処理場の汚泥
を濃度約３０００ｍｇ／Ｌに調整して用いた。Example 1 A synthetic wastewater mainly containing peptone and yeast extract (N
H 4 ) 2 SO 4 was added, and the COD concentration was 1000 mg /
L, the ammoniacal nitrogen concentration adjusted to 500 mg / L was used as raw water, and the nitrification denitrification treatment was performed according to the present invention. The sludge used was a sludge from a sewage treatment plant that had been subjected to nitrification and denitrification treatment, after being adjusted to a concentration of about 3000 mg / L.
【００３７】容積１０Ｌの曝気槽を２槽に仕切り、第１
槽で曝気下に亜硝酸型硝化を行い、第２槽で嫌気条件下
に脱窒反応を行った。原水は１日１０Ｌの流量で通水し
た。The aeration tank with a volume of 10 L is divided into two tanks,
Nitrite type nitrification was performed under aeration in the tank, and denitrification reaction was performed under anaerobic conditions in the second tank. Raw water was passed at a flow rate of 10 L per day.
【００３８】第１槽においては運転開始時に亜硝酸ナト
リウムをＮＯ２−Ｎとして５００ｍｇ／Ｌになるように
投入し、ＣＯＤ成分の分解細菌を阻害した状態で実験を
開始した。また、その後は曝気量を制限してＤＯ濃度を
０．４ｍｇ／Ｌ程度に保ち、亜硝酸型硝化を維持した。
第２槽では炭素源としてメタノールを添加した。また、
第２槽のＯＲＰを計測してその値を用いてメタノール添
加量を制御した。第２槽の流出液を固液分離して処理水
を得、分離汚泥を第１槽へ返送した。汚泥のＳＲＴ（汚
泥滞留時間）は１５日になるように、適宜余剰汚泥を引
き抜いた。In the first tank, sodium nitrite was added as NO 2 —N so as to be 500 mg / L at the start of operation, and the experiment was started in a state where the COD component-decomposing bacteria were inhibited. Further, thereafter, the aeration amount was limited to maintain the DO concentration at about 0.4 mg / L to maintain the nitrite type nitrification.
In the second tank, methanol was added as a carbon source. Also,
The ORP in the second tank was measured and the value was used to control the amount of methanol added. The effluent of the second tank was subjected to solid-liquid separation to obtain treated water, and the separated sludge was returned to the first tank. The excess sludge was appropriately withdrawn so that the SRT (sludge retention time) of the sludge was 15 days.
【００３９】この処理において、第１槽及び第２槽の処
理水のＣＯＤ、アンモニア性窒素、亜硝酸性窒素及び硝
酸性窒素濃度と、第２槽のメタノール添加量は表１に示
す通りであった。In this treatment, the COD, the ammonia nitrogen, the nitrite nitrogen and the nitrate nitrogen concentration of the treated water in the first tank and the second tank and the amount of methanol added in the second tank are as shown in Table 1. It was
【００４０】比較例１
実施例１において、運転開始時に亜硝酸ナトリウムを添
加せず、また、第１槽のＤＯ濃度を１．０〜１．５ｍｇ
／Ｌとしたこと以外は同様にして処理を行ったところ、
各槽の処理水の水質とメタノール添加量は、表１に示す
通りであった。Comparative Example 1 In Example 1, sodium nitrite was not added at the start of operation, and the DO concentration in the first tank was 1.0 to 1.5 mg.
When processed in the same manner except that / L was set,
The quality of treated water in each tank and the amount of methanol added were as shown in Table 1.
【００４１】[0041]
【表１】 [Table 1]
【００４２】表１より明らかなように、実施例１では第
１槽（硝化槽）において亜硝酸型硝化を行うと共に、Ｃ
ＯＤの分解を抑制したために、比較例１に比べて第２槽
（脱窒槽）のメタノール添加量を大幅に低減することが
できた。As is clear from Table 1, in Example 1, nitrite type nitrification was performed in the first tank (nitrification tank), and C
Since the decomposition of OD was suppressed, the addition amount of methanol in the second tank (denitrification tank) could be significantly reduced as compared with Comparative Example 1.
【００４３】また、亜硝酸型硝化を行ったことにより、
第１槽（硝化槽）の曝気量も比較例１に比べて大幅に低
減することができた。Further, by performing nitrite type nitrification,
The aeration amount in the first tank (nitrification tank) was also able to be significantly reduced as compared with Comparative Example 1.
【００４４】なお、得られた処理水の水質は実施例１と
比較例１とで殆ど差異はなく、良好な水質の処理水を得
ることができた。The quality of the treated water obtained was almost the same as that of Example 1 and Comparative Example 1, and treated water of good quality could be obtained.
【００４５】[0045]
【発明の効果】以上詳述した通り、本発明の硝化脱窒処
理方法によれば、アンモニア性窒素及びＣＯＤ成分を含
む原水の硝化脱窒処理に当たり、硝化工程において、亜
硝酸型硝化を行うことにより曝気コストを低減すると共
に、脱窒工程における炭素源の必要量を低減することが
できる。しかも、硝化工程においてＣＯＤ成分の分解を
抑制してこれを脱窒工程に導入することで、原水中のＣ
ＯＤ成分を脱窒工程の炭素源として利用することがで
き、脱窒工程において、炭素源の供給量を低減するか或
いは全く不要とすることができる。As described in detail above, according to the nitrification denitrification treatment method of the present invention, in the nitrification denitrification treatment of raw water containing ammoniacal nitrogen and COD components, nitrite type nitrification is performed in the nitrification step. As a result, the aeration cost can be reduced and the required amount of carbon source in the denitrification process can be reduced. Moreover, by suppressing the decomposition of the COD component in the nitrification process and introducing it into the denitrification process, C in the raw water is reduced.
The OD component can be used as a carbon source in the denitrification step, and in the denitrification step, the supply amount of the carbon source can be reduced or eliminated altogether.
【００４６】このため、従来、硝化脱窒処理において運
転コストの大部分を占めていた曝気コストと炭素源の添
加コストを大幅に低減して低コストで効率的な処理を行
える。Therefore, the aeration cost and the carbon source addition cost, which conventionally occupy most of the operation cost in the nitrification denitrification process, can be greatly reduced, and the low-cost and efficient process can be performed.
【図１】本発明の硝化脱窒処理方法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 nitrification denitrification treatment method of the present invention.
【符号の説明】 １ 硝化槽 ２ 脱窒槽 ３ 再曝気槽 ４ 沈殿槽[Explanation of symbols] 1 Nitrification tank 2 denitrification tank 3 re-aeration tank 4 settling tank
───────────────────────────────────────────────────── フロントページの続き (72)発明者 今城 麗 東京都新宿区西新宿三丁目４番７号 栗田 工業株式会社内 Ｆターム(参考） 4D040 BB02 BB52 BB91 BB92 BB93 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Rei Imajo Kurita, 3-4-3 Nishi-Shinjuku, Shinjuku-ku, Tokyo Industry Co., Ltd. F-term (reference) 4D040 BB02 BB52 BB91 BB92 BB93
Claims (2)
原水を硝化脱窒処理する方法において、 原水中の溶存酸素を低濃度に保持しながら、アンモニア
酸化細菌の存在下に亜硝酸型硝化反応を行うと共に蓄積
した亜硝酸性窒素の濃度阻害によりＣＯＤ分解細菌を抑
制する硝化工程と、 該硝化工程で生成した亜硝酸性窒素を、残留するＣＯＤ
成分を電子供与体として脱窒細菌の作用により脱窒する
脱窒工程とを有することを特徴とする硝化脱窒処理方
法。1. A method for nitrifying and denitrifying raw water containing ammoniacal nitrogen and COD components, wherein nitrite-type nitrification reaction is carried out in the presence of ammonia-oxidizing bacteria while keeping dissolved oxygen in the raw water at a low concentration. The nitrification step of suppressing COD-degrading bacteria by inhibiting the concentration of nitrite nitrogen accumulated with the COD remaining in the nitrification nitrogen produced in the nitrification step.
And a denitrification step of denitrifying the components as electron donors by the action of denitrifying bacteria.
性窒素濃度が所定濃度となるように亜硝酸性窒素を添加
する請求項１に記載の硝化脱窒処理方法。2. The nitrification denitrification treatment method according to claim 1, wherein at the start of the treatment, nitrite nitrogen is added so that the concentration of nitrite nitrogen in the nitrification step becomes a predetermined concentration.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005131451A (en) * | 2003-10-28 | 2005-05-26 | Kobelco Eco-Solutions Co Ltd | Nitrification method for ammonia nitrogen-containing wastewater |
| JP2008049283A (en) * | 2006-08-25 | 2008-03-06 | Japan Organo Co Ltd | Water treatment apparatus |
| CN102417272A (en) * | 2011-02-18 | 2012-04-18 | 江苏省纯江环保科技有限公司 | Coking waste water treatment method and A / O technology apparatus |
| KR101208190B1 (en) | 2011-09-01 | 2012-12-04 | 서울시립대학교 산학협력단 | Analizing methods of chemical oxygen demand(cod) using ultrasound digestion and oxidation-reduction potential based titration |
| KR20200090265A (en) | 2017-12-13 | 2020-07-28 | 각코호진 토요다이가쿠 | Anamox bacteria support carrier for wastewater treatment and anomax flora attachment, and wastewater treatment apparatus using the attachment |
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| KR101208190B1 (en) | 2011-09-01 | 2012-12-04 | 서울시립대학교 산학협력단 | Analizing methods of chemical oxygen demand(cod) using ultrasound digestion and oxidation-reduction potential based titration |
| KR20200090265A (en) | 2017-12-13 | 2020-07-28 | 각코호진 토요다이가쿠 | Anamox bacteria support carrier for wastewater treatment and anomax flora attachment, and wastewater treatment apparatus using the attachment |
| US11427489B2 (en) | 2017-12-13 | 2022-08-30 | Toyo University | Carrier for retaining anammox bacteria for use in wastewater treatment, anammox bacteria-adhered particle, and wastewater treatment apparatus using the carrier |
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