JPH1094796A - Treatment of waste water and device therefor - Google Patents
Treatment of waste water and device thereforInfo
- Publication number
- JPH1094796A JPH1094796A JP25022396A JP25022396A JPH1094796A JP H1094796 A JPH1094796 A JP H1094796A JP 25022396 A JP25022396 A JP 25022396A JP 25022396 A JP25022396 A JP 25022396A JP H1094796 A JPH1094796 A JP H1094796A
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- tank
- aerobic
- reaction tank
- vessel
- anoxic
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Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は汚水の生物学的処理
方法に関する。The present invention relates to a biological treatment method for wastewater.
【0002】[0002]
【従来の技術】従来、汚水中から生物学的に窒素成分を
除去する方法としては循環式硝化脱窒法が用いられてき
た。この方法は、脱窒槽及び最終沈殿池を設け、脱窒槽
に硝化槽処理水の一部と沈殿池からの返送汚泥を導入
し、脱窒槽で脱窒細菌の作用によりNO2 −N及び又は
NO3 −N(以下NO2 −NとNO3 −Nを総称してN
OX −Nと記す)を窒素ガスに還元し、汚水からの窒素
成分の除去を行い、硝化槽で好気的条件下で硝化細菌の
作用によりアンモニア性窒素(NH4 −N)や有機性窒
素をNOX −Nに酸化するもので、硝化槽処理液の一部
は前述のように脱窒槽に循環し、残りの硝化槽処理液は
最終沈殿池に導入され、上澄液として処理水が得られ、
沈殿汚泥の一部は前述のように脱窒槽に返送される(返
送汚泥)。返送汚泥の一部は余剰汚泥として引き抜かれ
る。2. Description of the Related Art Conventionally, as a method for biologically removing nitrogen components from wastewater, a circulating nitrification denitrification method has been used. In this method, a denitrification tank and a final sedimentation basin are provided, a part of the nitrification tank treatment water and return sludge from the sedimentation basin are introduced into the denitrification tank, and NO 2 -N and / or NO 3 -N (hereinafter, NO 2 -N and NO 3 -N are collectively referred to as N
The O X referred to as -N) was reduced to nitrogen gas, subjected to removal of nitrogen components from the wastewater, ammonia nitrogen by the action of nitrifying bacteria under aerobic conditions in the nitrification reactor (NH 4 -N) and organic nitrogen those oxidized to NO X -N, some of nitrification tank processing solution is circulated in the aforementioned manner denitrification tank, the remaining nitrification tank treatment liquid is introduced into the settling tank, the treated water as a supernatant Is obtained,
Part of the settled sludge is returned to the denitrification tank as described above (returned sludge). Part of the returned sludge is extracted as excess sludge.
【0003】この処理過程では、脱窒槽で、脱窒のため
の還元剤として、BOD成分が利用されるため、脱窒槽
でもBOD成分の一部が除去されるが、大部分の汚水中
のBOD成分は好気槽において好気的条件下で分解除去
される。[0003] In this treatment process, since the BOD component is used as a reducing agent for denitrification in the denitrification tank, a part of the BOD component is also removed in the denitrification tank. The components are decomposed and removed under aerobic conditions in an aerobic tank.
【0004】さらに、上述の方法において、微生物固定
化担体を用いることにより硝化菌を高濃度に反応槽内に
保持し、反応槽を小型化する技術の開発が行われてき
た。このような技術は文献1、特公平5−46279お
よび特開昭63−97290などにすでに記載されてい
る。これらの技術では、硝化槽に担体を投入することに
より、硝化槽内部に硝化菌を高濃度に維持できるので、
硝化槽を大幅に小型化できるものとされている。Further, in the above-mentioned method, a technique has been developed in which nitrifying bacteria are held in a reaction tank at a high concentration by using a microorganism-immobilized carrier, and the reaction tank is reduced in size. Such a technique has already been described in Document 1, Japanese Patent Publication No. 5-46279, and Japanese Patent Application Laid-Open No. 63-97290. In these technologies, by introducing a carrier into the nitrification tank, nitrifying bacteria can be maintained at a high concentration inside the nitrification tank,
It is said that the nitrification tank can be significantly reduced in size.
【0005】また、特開平7−39899に、脱窒槽と
微生物固定化担体を用いた硝化槽の間に、微生物固定化
担体を投入しな好気槽を設けた例が記載されている。こ
こにおける好気槽の役割は、有機物を分解して担体への
過剰の微生物、特に糸状性細菌の付着を防ぐこととされ
ている。Japanese Patent Application Laid-Open No. Hei 7-39899 describes an example in which an aerobic tank is provided between a denitrification tank and a nitrification tank using a microorganism-immobilized carrier, in which the microorganism-immobilized carrier is not charged. The role of the aerobic tank here is to decompose the organic matter and prevent excessive microorganisms, particularly filamentous bacteria, from adhering to the carrier.
【0006】なお、反応槽に酸素を供給し、反応槽内を
好気性状態に保つ方法としてはジェットエアレータなど
のエアレータを用いる方法、散気板、ディフューザ等を
反応槽内に設置し、これらを通して酸素含有ガスを反応
槽に吹き込む方法等が公知の事実である。As a method of supplying oxygen to the reaction tank and keeping the inside of the reaction tank in an aerobic state, a method using an aerator such as a jet aerator, a diffuser plate, a diffuser, and the like are installed in the reaction tank, and through these, A method of blowing an oxygen-containing gas into a reaction tank is a known fact.
【0007】次に、無酸素条件で反応槽内を撹拌する方
法としては、反応槽内部に水中撹拌機を設置する方法、
反応槽内部循環用ポンプを設置する方法、反応槽上部に
撹拌機を設置する方法、および反応槽の上部空間を密閉
構造とし反応槽に反応槽上部空間に存在する気体を繰り
返し吹き込む方法などがある。Next, as a method of stirring the inside of the reaction tank under oxygen-free conditions, a method of installing a submersible stirrer inside the reaction tank,
There are a method of installing a pump for circulating the inside of the reaction tank, a method of installing a stirrer at the top of the reaction tank, and a method of repeatedly blowing gas existing in the upper space of the reaction tank into the reaction tank by making the upper space of the reaction tank a closed structure. .
【0008】また、反応槽内に粗大径の気泡が発生する
散気装置を設置し、この散気装置に空気を吹き込むこと
によって反応槽内を撹拌する方法も開発されつつある
(文献2)。Further, a method has been developed in which a diffuser for generating bubbles having a large diameter is installed in a reaction tank, and the inside of the reaction tank is stirred by blowing air into the diffuser (Reference 2).
【0009】文献1:包括固定化担体を用いた硝化促進
型循環変法「ペガサス」の評価に関する報告書、日本下
水道事業団技術開発部編著、平成5年6月 文献2:小西ら、散気装置による嫌気タンクの旋回流式
撹拌装置、第33回下水道研究発表会公演集、日本下水
道協会(1995)Reference 1: A report on the evaluation of a modified nitrification-promoting circulating method "Pegasus" using a comprehensive immobilized carrier, edited by the Technology Development Department, Japan Sewerage Corporation, June 1993 Reference 2: Konishi et al. Swirling stirrer for anaerobic tanks using the device, 33rd Sewer Research Conference Performance Collection, Japan Sewer Association (1995)
【0010】[0010]
【発明が解決しようとする課題】従来の技術では、曝気
槽における各反応槽の容積の絶対値および容積比は、プ
ラントが建設されてしまうと常に一定であるため、流入
水の水質や水量の変動に対して必ずしも最適な槽構成と
はなり得ず、処理水質の悪化を招く場合があった。In the prior art, the absolute value and the volume ratio of each reaction tank in the aeration tank are always constant after the plant has been constructed. It was not always possible to obtain an optimum tank configuration with respect to fluctuations, and the quality of treated water was sometimes deteriorated.
【0011】即ち、各反応槽の容積の絶対値および容積
比は、流入水質、流入水量および処理水質を想定したう
えで、BOD除去速度、アンモニア酸化速度(以下、硝
化速度と記す)、および脱窒速度等の反応速度を用い
て、最適解として決定される。このことは、逆に言え
ば、流入水質等の条件が想定値と異なる場合には、想定
値を用いて設計されたプラントの槽構成が最適なもので
はないことを意味する。That is, the absolute value and the volume ratio of the volume of each reaction tank are determined based on the inflow water quality, the inflow water amount and the treated water quality, and the BOD removal rate, ammonia oxidation rate (hereinafter referred to as nitrification rate), and desorption rate. It is determined as an optimal solution using a reaction rate such as a nitrogen rate. Conversely, if conditions such as inflow water quality are different from the assumed values, this means that the tank configuration of the plant designed using the assumed values is not optimal.
【0012】しかるに、実際の排水処理施設の運転状況
は、一日の間に流入水量および流入水質の変動があり、
流入水量および流入水中の汚濁物質の濃度は平均値に対
して50%から150%程度の範囲で変動することが一
般的である。また、流入水質、流入水量の季節変動も見
られ、夏期と比べて冬季は流入水量は10%から20%
程度低下し、流入水中の汚濁物質濃度は10%から20
%程度増大することが一般的である。また、流入水中の
BOD成分と窒素系の汚濁物質の成分の比率も時間変動
および季節変動することが知られている。[0012] However, the actual operation status of the wastewater treatment facility is such that the amount of inflow water and the quality of inflow water fluctuate during one day.
In general, the amount of influent water and the concentration of pollutants in the influent water vary within a range of about 50% to 150% with respect to the average value. In addition, seasonal fluctuations in inflow water quality and inflow volume are also observed. In winter, inflow is 10% to 20% compared to summer.
And the concentration of pollutants in the influent is 10% to 20%.
It is common to increase by about%. It is also known that the ratio of the BOD component and the nitrogen-based pollutant component in the influent varies with time and with season.
【0013】では次に、循環型硝化脱窒法のシステムを
例にとり、流入水質の変動の与える処理水質への影響を
考察する(具体的な実験結果は、実施例の項に記述す
る)。以下に設計の想定条件を記す。Next, the effect of fluctuations in the inflow water quality on the treated water quality will be considered, taking the system of the circulation type nitrification and denitrification method as an example (specific experimental results are described in the Examples section). The assumed conditions of the design are described below.
【0014】流入水のBODをBI(g/m3 )、全窒
素濃度をNI(g/m3 )(全窒素はすべて硝化可能な
窒素と仮定)、反応槽内の汚泥濃度(MLSS)をX
(g/m3 )とする。The BOD of the inflow water is BI (g / m 3 ), the total nitrogen concentration is NI (g / m 3 ) (all nitrogen is assumed to be nitrifying nitrogen), and the sludge concentration (MLSS) in the reaction tank is X
(G / m 3 ).
【0015】処理水の全窒素の目標値をNE(g/m
3 )とする。脱窒槽では流入するNOX −Nをすべて窒
素ガスまで脱窒するものとする。硝化槽では流入する硝
化可能な窒素成分をすべてNOX −Nまで硝化するもの
とする。The target value of the total nitrogen of the treated water is NE (g / m
3 ). In the denitrification tank shall denitrification until all nitrogen gas NO X -N flowing. The nitrification tank shall nitrification nitrification possible nitrogen components flowing until all NO X -N.
【0016】処理水中の窒素成分はNOX −Nの形態で
のみ存在するものとする。硝化槽からの循環比をr1 、
最終沈殿池からの返送比をr2 とし、R=r1 +r2 と
する。It is assumed that the nitrogen component in the treated water exists only in the form of NO x -N. The circulation ratio from the nitrification tank is r1,
The return ratio from the final sedimentation basin is r2, and R = r1 + r2.
【0017】硝化速度をKN(gN/m3 /d)とす
る。脱窒速度KDは脱窒槽および硝化槽を併せた槽での
汚泥量に対するBOD−SS負荷(Ls )の関数として
(1)式で示される。The nitrification rate is defined as KN (gN / m 3 / d). The denitrification rate KD is expressed by the equation (1) as a function of the BOD-SS load (Ls) with respect to the amount of sludge in the combined denitrification tank and nitrification tank.
【0018】 KD=k・Ls (gN/gMLSS/d) (1) ここに、 k:脱窒速度定数(gN/gBOD ) また、Ls は(2)式で表される。KD = k · Ls (gN / gMLSS / d) (1) where, k: denitrification rate constant (gN / gBOD), and Ls is represented by equation (2).
【0019】 Ls =Q・BI/(VD+VN)/X(gBOD /gMLSS/d) (2) ここに、VD:脱窒槽容積(m3 ) VN:硝化槽容積(m3 ) Q:流入水量(m3 /d) 以上の想定条件によりVNおよびVDは、それぞれ
(3)式および(4)式で求めることができる。[0019] Ls = Q · BI / (VD + VN) / X (gBOD / gMLSS / d) (2) Here, VD: denitrification tank volume (m 3) VN: nitrification tank volume (m 3) Q: inflow water amount ( m 3 / d) Under the above assumed conditions, VN and VD can be obtained by equations (3) and (4), respectively.
【0020】 VN=Q・NI/(KN/・X) (3) VD=Q・R・NE/(KD・X) (4) ここに、NE:処理水の全窒素濃度(g/m3 )ところ
で、処理水の全窒素をNE(g/m3 )以下とするため
に必要なRの値は(5)式で与えられる。VN = Q · NI / (KN / · X) (3) VD = Q · R · NE / (KD · X) (4) where NE: total nitrogen concentration of treated water (g / m 3) ) By the way, the value of R required to make the total nitrogen of the treated water equal to or less than NE (g / m 3 ) is given by equation (5).
【0021】 R=(NI−NE)/NE (5) よって、(1)式から(5)式を計算することによっ
て、VNとVDを計算することができる。R = (NI−NE) / NE (5) Therefore, VN and VD can be calculated by calculating Expression (5) from Expression (1).
【0022】次に、以下の数値条件を仮定して容量計算
を行ってみる。 (容量計算に使用する値:ケース1) Q=10000(m3 /d)、NI=40(g/m
3 )、NE=10(g/m3 )、BI=150(g/m
3 ),X=2000(g/m3 )、k=0.48(gN
/gBOD )、KN=0.048(gN/gMLSS/d) 以上の値をを用いて計算すると、VN=4170(m
3 )、VD=2980(m3 )という値が得られ、反応
槽合計容積は7150(m3 )となる。Next, a capacity calculation will be performed on the assumption of the following numerical conditions. (Value used for capacity calculation: Case 1) Q = 10000 (m 3 / d), NI = 40 (g / m
3 ), NE = 10 (g / m 3 ), BI = 150 (g / m 3 )
3 ), X = 2000 (g / m 3 ), k = 0.48 (gN
/ GBOD), KN = 0.048 (gN / gMLSS / d) By using the above values, VN = 4170 (m
3 ), VD = 2980 (m 3 ) is obtained, and the total volume of the reaction tank is 7150 (m 3 ).
【0023】これに対して、流入水量が変化してNIが
35(g/m3 )まで、BIか110(g/m3 )まで
低下した場合(ケース2)を想定し、他の値は上記の容
量計算で使用した値を用いるとVN′=3650(m
3 )、VD′=3280(m3),反応槽合計容積は6
930(m3 )という値が得られる。On the other hand, assuming a case where the amount of inflow water changes and the NI drops to 35 (g / m 3 ) and the BI drops to 110 (g / m 3 ) (case 2), the other values are Using the value used in the above capacity calculation, VN '= 3650 (m
3), VD '= 3280 ( m 3), the reaction vessel total volume 6
A value of 930 (m 3 ) is obtained.
【0024】この試算例では、VN′<VNであるため
100%硝化は行われるが、VD′>VDとなり、ケー
ス1で想定した流入水質を前提として脱窒槽容積をVD
として設計された処理施設に、ケース2で想定した水質
の流入水が流入した場合には脱窒槽容積が不足するた
め、処理水中にNOX −Nが残留して処理水質が悪化す
ることが示されている。In this calculation example, since VN '<VN, 100% nitrification is performed, but VD'> VD, and the volume of the denitrification tank is assumed to be VD on the assumption of the inflow water quality assumed in Case 1.
When the inflow water of the water quality assumed in Case 2 flows into the treatment facility designed as the above, the capacity of the denitrification tank is insufficient, indicating that NO X -N remains in the treated water and the treated water quality deteriorates. Have been.
【0025】ここで、特徴的なことは、ケース2ではB
I,NIともケース1より小さい値を想定しているにも
かかわらず処理水の全窒素濃度はケース2の方が高い値
となることが示されている点であり、従来のBOD成分
除去を中心とする生物学的水処理技術においては、流入
水中の汚濁物質濃度の低下は一般的に処理水質の向上に
結びついていたが、上述した循環式硝化脱窒法や嫌気−
無酸素−好気法の場合には、必ずしも処理水の全窒素濃
度の向上には結びつかないことが示されている。Here, the characteristic point is that in case 2, B
Although it is shown that the total nitrogen concentration of the treated water is higher in Case 2 even though both I and NI are assumed to be smaller than Case 1, the conventional BOD component removal was performed. In biological water treatment technology, which is the center, a decrease in the concentration of pollutants in influent water has generally led to an improvement in the quality of treated water.
It is shown that in the case of the anoxic-aerobic method, it does not necessarily lead to an increase in the total nitrogen concentration of the treated water.
【0026】このように、流入水中の汚濁物質濃度が低
下しても処理水の全窒素濃度が悪化する原因は、(1)
式および(2)式から分かるように、脱窒速度がBIに
比例するためであり、BIの濃度の変動は処理水質に大
きな影響を与える。As described above, even if the concentration of pollutants in the influent water decreases, the cause of the deterioration of the total nitrogen concentration of the treated water is as follows (1).
As can be seen from the equation and the equation (2), this is because the denitrification rate is proportional to the BI, and the fluctuation of the BI concentration greatly affects the quality of the treated water.
【0027】次に、硝化−内生脱窒法と呼ばれる処理方
式の処理フローにおいては、反応槽の構成は好気槽、無
酸化槽および再曝気槽の構成となる。硝化−内生脱窒法
では、好気槽でアンモニア性窒素や有機性窒素等の硝化
可能な窒素成分をNOX −Nに硝化した後、脱窒槽(無
酸素槽)で脱窒して窒素系汚濁物質の処理を行うもので
ある。Next, in the processing flow of the processing method called the nitrification-endogenous denitrification method, the configuration of the reaction tank is an aerobic tank, a non-oxidizing tank, and a re-aeration tank. Nitrification - The endogenous denitrification, after nitrification possible nitrogen components such as ammonia nitrogen and organic nitrogen in aerobic tank and nitrification in NO X -N, nitrogen system and denitrification in the denitrification tank (anoxic tank) It is for treating pollutants.
【0028】この方法は、前述の循環法とは異なり、理
論的には100%の脱窒が可能な方法であるが、脱窒反
応の還元剤であるBOD成分が前段の好気槽で好気的に
分解されるため、脱窒速度が小さくなり、そのために大
型の反応槽が必要であるという欠点がある。脱窒速度を
増大させ、脱窒槽容積を低減する方法として脱窒槽にメ
タノール等の還元剤を投入する方法もあるが、この場合
には処理費用が増大するという問題がある。This method is different from the above-mentioned circulation method, and is theoretically a method capable of denitrification of 100%. However, the BOD component which is a reducing agent for the denitrification reaction is preferably used in the preceding aerobic tank. Since it is decomposed by gas, the denitrification rate is reduced, and thus a large-sized reaction tank is required. As a method of increasing the denitrification rate and reducing the capacity of the denitrification tank, there is also a method of introducing a reducing agent such as methanol into the denitrification tank, but in this case, there is a problem that the processing cost increases.
【0029】また、反応槽を無酸素条件で撹拌する方法
としては粗大気泡を発生する散気装置を反応槽内に設置
する方法があるが、散気量の低減、撹拌エネルギの向上
といった課題がある。As a method of stirring the reaction tank under oxygen-free conditions, there is a method of installing a diffuser for generating coarse bubbles in the reaction tank. However, there are problems such as reduction of the amount of diffused air and improvement of stirring energy. is there.
【0030】本発明は上記のような事情に鑑みてなされ
たもので、流入水質、処理水質および処理水量に応じ
て、安定して良好な処理水質が確保できるようにするこ
と。また、脱窒の還元剤が不足する場合にも、投入還元
性物質の投入量を削減できるようにした廃水の処理方法
を提供することを課題とするものである。The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to ensure a stable and good quality of treated water according to the quality of inflow water, treated water and the amount of treated water. It is another object of the present invention to provide a method for treating wastewater that can reduce the amount of input reducing substances even when the denitrifying reducing agent is insufficient.
【0031】[0031]
【課題を解決するための手段】本発明の廃水の処理方法
は、好気条件下の好気槽において生物的に酸化すること
と、無酸素条件下の無酸素槽で生物的に脱窒することを
組合わせて廃水中の窒素系汚濁物資を除去する廃水の処
理方法において、前記好気槽と無酸素槽の中間に少なく
とも一つの中間反応槽を設け、好気条件と無酸素条件の
いずれの条件においても運転可能とすることができるこ
とを特徴とするものである。SUMMARY OF THE INVENTION The wastewater treatment method of the present invention comprises biologically oxidizing in an aerobic tank under aerobic conditions and biologically denitrifying in an anoxic tank under anoxic conditions. In a wastewater treatment method for removing nitrogen-based pollutants in wastewater by combining the above, at least one intermediate reaction tank is provided between the aerobic tank and the anoxic tank, and any of the aerobic condition and the anoxic condition is provided. It can be operated even under the following conditions.
【0032】これにより、無酸素槽と好気槽の中間に設
置される中間反応槽を、流入水質、処理水質および処理
水量に応じて好気状態あるいは無酸素(嫌気)状態に維
持して、好気槽あるいは無酸素槽の容積を必要に応じて
増大させることによって、安定して良好な処理水質を得
ることができ、またメタノール等の還元剤を用いる場合
でも、還元剤の使用量の削減効果が得られる。Thus, the intermediate reaction tank installed between the anoxic tank and the aerobic tank is maintained in an aerobic state or an anoxic (anaerobic) state depending on the quality of the inflow water, the quality of the treated water, and the amount of treated water. By increasing the capacity of the aerobic tank or the oxygen-free tank as necessary, it is possible to stably obtain good treated water quality, and even when using a reducing agent such as methanol, it is possible to reduce the amount of the reducing agent used. The effect is obtained.
【0033】そして、本発明による廃水の処理装置は、
好気条件下で生物的に酸化を行う好気槽と、無酸素条件
下で生物的に脱窒を行う無酸素槽とを有して、廃水中の
窒素系汚濁物資の除去を行う廃水の処理装置において、
前記好気槽と前記無酸素槽の中間に、散気装置等により
行う好気条件と撹拌装置等により行う無酸素条件のいず
れの条件においても運転可能な少なくとも一つの中間反
応槽を設けて構成されている。The wastewater treatment apparatus according to the present invention
An aerobic tank that oxidizes biologically under aerobic conditions, and an anoxic tank that biologically denitrifies under anoxic conditions, and wastewater that removes nitrogen-based pollutants in the wastewater In the processing device,
In the middle of the aerobic tank and the anoxic tank, at least one intermediate reaction tank operable under any of aerobic conditions performed by a diffuser or anoxic conditions performed by a stirrer is provided. Have been.
【0034】この廃水の処理装置で、前記好気槽は微生
物固定化担体を有している。これによって、好気槽を大
幅に小型化することができる。また、中間反応槽が好気
条件で運転されている場合には、微生物固定化担体に硝
化細菌が優先種として付着するため硝化処理の高速化と
安定化という効果が得られる。In this wastewater treatment apparatus, the aerobic tank has a microorganism-immobilized carrier. Thereby, the size of the aerobic tank can be significantly reduced. In addition, when the intermediate reaction tank is operated under aerobic conditions, nitrifying bacteria adhere to the microorganism-immobilized carrier as a preferential species, so that the effect of increasing the speed and stabilizing the nitrification treatment can be obtained.
【0035】また、中間反応槽に設けた撹拌装置は、粗
大気泡を発生する散気装置となっている。この散気装置
に空気を吹き込むことにより、中間反応槽を無酸素条件
で撹拌する。これにより、水中への酸素の溶解を制限し
つつ中間槽を撹拌することができる。Further, the stirring device provided in the intermediate reaction tank is a diffuser for generating coarse bubbles. By blowing air into the air diffuser, the intermediate reaction tank is stirred under oxygen-free conditions. Thereby, the intermediate tank can be stirred while limiting the dissolution of oxygen in water.
【0036】また、粗大気泡を発生する散気装置が設け
られた中間反応槽には槽内の液が上昇する部分と下降す
る部分とに区分する、ドラフトチューブやバッフル板等
が設けられている。In the intermediate reaction tank provided with a diffuser for generating coarse bubbles, a draft tube, a baffle plate, and the like are provided for dividing the liquid in the tank into a rising part and a falling part. .
【0037】これにより、気泡が液の上昇流に同伴され
て上昇し、かつ、気泡が液流速に対して上向きのスリッ
プ速度を有するため、気泡の液中での滞留時間(気液接
触時間)が短くなり、酸素の溶解量をさらに低減させる
ことができると共に、槽内の撹拌エネルギも増大し、よ
り良好な撹拌状態を得ることができる。As a result, the bubbles rise along with the upward flow of the liquid, and the bubbles have an upward slip speed with respect to the liquid flow velocity, so that the residence time of the bubbles in the liquid (gas-liquid contact time) , The amount of dissolved oxygen can be further reduced, and the stirring energy in the tank increases, so that a better stirring state can be obtained.
【0038】また、粗大気泡を発生する散気装置が設け
られた中間反応槽の底部の少なくとも一部が凹形状にな
っている。これにより、汚泥は凹部に沈降、集積し、エ
アリフト効果によって再び中間槽上部に移送されるた
め、底部への汚泥の堆積を防ぎつつ、槽内の良好な撹拌
状態を得ることができる。Further, at least a part of the bottom of the intermediate reaction tank provided with an air diffuser for generating coarse bubbles has a concave shape. Thereby, the sludge settles and accumulates in the concave portion, and is again transferred to the upper portion of the intermediate tank by the air lift effect. Therefore, it is possible to obtain a good stirring state in the tank while preventing sludge from accumulating on the bottom portion.
【0039】また、中間反応槽における粗大気泡を発生
する散気装置が間欠的に運転されるようになっている。
これにより、中間槽内への酸素の溶解量を低減した運転
が可能となり、良好な窒素除去が達成される。A diffuser for generating coarse bubbles in the intermediate reaction tank is operated intermittently.
As a result, an operation in which the amount of dissolved oxygen in the intermediate tank is reduced becomes possible, and good nitrogen removal is achieved.
【0040】また、中間反応槽の上部空間が密閉構造と
され、この槽の上部空間に存在する気体を繰り返し槽内
に吹き込む装置が設けられている。この構成により、上
部空間に存在する気体を繰り返し槽内に吹き込むことに
よって、吹き込みガス中の酸素濃度が徐々に低下し、中
間槽内への酸素の溶解量を大幅に低減させた運転が可能
となり、良好な窒素除去が達成される。The upper space of the intermediate reaction tank has a closed structure, and a device for repeatedly blowing gas existing in the upper space of the tank into the tank is provided. With this configuration, the gas present in the upper space is repeatedly blown into the tank, whereby the oxygen concentration in the blown gas gradually decreases, and the operation in which the amount of dissolved oxygen in the intermediate tank is greatly reduced becomes possible. , Good nitrogen removal is achieved.
【0041】[0041]
【発明の実施の形態】図1は本発明の実施の形態の一例
を示す全体構成図である。これは、循環型硝化脱窒法の
無酸素槽と硝化層の間に中間槽を設けたもので、流入水
1は、無酸素槽3,中間槽4および好気層6で処理を受
ける。FIG. 1 is an overall configuration diagram showing an example of an embodiment of the present invention. This is provided with an intermediate tank between the anoxic tank of the circulating type nitrification and denitrification method and the nitrification layer, and the inflow water 1 is treated in the anoxic tank 3, the intermediate tank 4, and the aerobic layer 6.
【0042】好気層6では、流入水1中のアンモニア性
窒素や有機性窒素等がNOX −Nに酸化され、その一部
はは循環ライン9を経て無酸素槽3に循環され、ここで
脱窒処理がなされる。In the aerobic layer 6, ammonia nitrogen, organic nitrogen and the like in the influent 1 are oxidized to NO x -N, and a part thereof is circulated to the anoxic tank 3 through the circulation line 9. Denitrification treatment is performed.
【0043】中間槽4は、流入水質や水温、処理水質な
どに応じて無酸素条件あるいは好気条件で運転される。
中間槽4を無酸素条件で運転する場合には撹拌機8が用
いられ、好気条件で運転で運転する場合には散気装置5
から酸素含有ガスが吹き込まれる。The intermediate tank 4 is operated under anoxic condition or aerobic condition depending on the quality of inflow water, water temperature, treated water quality, and the like.
The stirrer 8 is used when the intermediate tank 4 is operated in an oxygen-free condition, and the diffuser 5 is used when the intermediate tank 4 is operated in an aerobic condition.
, An oxygen-containing gas is blown.
【0044】図2は、硝化−内生脱窒法の好気槽(硝化
槽)と無酸素槽(脱窒槽)の中間に中間槽を設けたもの
で、流入水1は、好気層11,中間槽12,無酸素槽1
3及び再曝気槽14の順に処理を受ける。FIG. 2 shows an intermediate tank provided between an aerobic tank (nitrification tank) and an anoxic tank (denitrification tank) in the nitrification-endogenous denitrification method. Intermediate tank 12, oxygen-free tank 1
3 and the re-aeration tank 14 in this order.
【0045】流入水1中のアンモニア性窒素や有機性窒
素等は、好気層11でNOX −Nに酸化される。中間槽
12は、好気槽11でほぼ100%に硝化が達成されて
いる場合には無酸素条件で、また、好気槽11での硝化
が不十分な場合には好気条件で運転される。中間槽12
を無酸素条件で運転する場合には、粗大気泡発生装置1
5から散気を行うことにより中間槽12の撹拌を行う。
一方、中間槽12を好気条件で運転する場合には、散気
装置5から酸素含有ガスが吹き込まれる。Ammonia nitrogen, organic nitrogen and the like in the influent 1 are oxidized to NO x -N in the aerobic layer 11. The intermediate tank 12 is operated under anoxic condition when nitrification is achieved to almost 100% in the aerobic tank 11, and is operated under aerobic condition when nitrification in the aerobic tank 11 is insufficient. You. Intermediate tank 12
Is operated under oxygen-free conditions, the coarse bubble generator 1
By aeration from step 5, the intermediate tank 12 is stirred.
On the other hand, when the intermediate tank 12 is operated under aerobic conditions, an oxygen-containing gas is blown from the air diffuser 5.
【0046】無酸素槽13においてはNOX −Nの脱窒
処理が行われる。脱窒速度を上昇させるために無酸素槽
13にメタノール等の還元剤を投入することもできる。
メタノール等の還元剤は、中間槽12を無酸素条件で運
転する場合には中間槽12に、一方、中間槽12を好気
条件で運転する場合には、無酸素槽13に投入する。The denitrification of NO X -N in the anoxic tank 13 is performed. In order to increase the denitrification rate, a reducing agent such as methanol can be introduced into the anoxic tank 13.
A reducing agent such as methanol is charged into the intermediate tank 12 when the intermediate tank 12 is operated under oxygen-free conditions, and is charged into the oxygen-free tank 13 when the intermediate tank 12 is operated under aerobic conditions.
【0047】再曝気槽14は、利用されなかったメタノ
ールを分解することや、無酸素槽13で発生した窒素ガ
スを汚泥から剥離させて、最終沈殿池7における汚泥の
分離を改善することを目的として設置されるが、要求処
理水質によっては再曝気槽14は不必要となる場合もあ
る。The re-aeration tank 14 aims to decompose unused methanol and to separate nitrogen gas generated in the oxygen-free tank 13 from sludge to improve the separation of sludge in the final sedimentation tank 7. However, the re-aeration tank 14 may not be required depending on the required quality of treated water.
【0048】ところで、硝化−内生脱窒法における好気
槽は一般的に窒素系汚濁物質の濃度が高く、かつ硝化速
度の低下する水温の低い冬季の条件を元に設計されるた
め、硝化速度が高くなる水温の高い時期や、流入水の窒
素系汚泥物質濃度が低い場合には必要以上の処理装置と
なっていることになる。Incidentally, the aerobic tank in the nitrification-endogenous denitrification method is generally designed on the basis of winter conditions in which the concentration of nitrogen-based pollutants is high and the nitrification rate is low and the water temperature is low. When the water temperature is high, or when the concentration of the nitrogen-based sludge substance in the inflow water is low, the processing apparatus is more than necessary.
【0049】このような高水温あるいは流入水の窒素系
汚泥物質が低濃度の場合、中間反応槽を設けた本発明に
おいては、小型の好気槽にあっても100%の硝化が達
成されるため、中間槽を無酸素槽として利用でき、無酸
素槽の総槽容積が増大するため、脱窒が十分に行われ、
流入水中のBOD成分あるいは汚泥の含有しているBO
D成分が還元剤として有効に利用されるため、メタノー
ル等の還元剤を投入する場合においても、その使用量を
削減できるという利点がある。When the nitrogen sludge substance at such a high water temperature or inflow water has a low concentration, in the present invention provided with an intermediate reaction tank, 100% nitrification can be achieved even in a small aerobic tank. Therefore, the intermediate tank can be used as an oxygen-free tank, and the total tank volume of the oxygen-free tank increases, so that denitrification is sufficiently performed.
BO containing influent BOD component or sludge
Since the D component is effectively used as a reducing agent, there is an advantage that the amount of the reducing agent can be reduced even when a reducing agent such as methanol is introduced.
【0050】また、硝化−内生脱窒法において、好気条
件での処理が進むほど内生脱窒速度は低下することが知
られているが、中間槽を無酸素槽として利用すると好気
槽容積が小さくなるため、内生脱窒速度が大となり、さ
らに無酸素槽の槽容積が中間槽の容積分だけ増大するた
めにメタノールの添加量を大幅に低減でき、またメタノ
ールの添加を行わない場合においても、処理水質は大幅
に改善される。In the nitrification-endogenous denitrification method, it is known that the rate of endogenous denitrification decreases as the treatment under aerobic conditions progresses. Because the volume is small, the rate of endogenous denitrification is high, and the volume of the oxygen-free tank is increased by the volume of the intermediate tank, so that the amount of methanol can be significantly reduced, and methanol is not added. Even in such cases, treated water quality is greatly improved.
【0051】なお、図1及び図2は本発明の例を示した
ものであり、本発明の効果は、無酸素槽と好気槽の中間
に設置される中間反応槽を、流入水質、処理水質や流入
水量に応じてフレキシブルに好気状態あるいは嫌気状態
に維持することによって得られるものであるため、図1
及び図2の他にも、嫌気−無酸素−好気法、UCT法や
嫌気−無酸素−好気−第2脱窒−再曝気といった無酸素
槽と好気槽あるいは好気槽と無酸素槽が結ばれたすべて
のシステムで効果が得られる。FIGS. 1 and 2 show an example of the present invention. The effect of the present invention is that an intermediate reaction tank installed between an oxygen-free tank and an aerobic tank is used for controlling inflow water quality and treatment Since it is obtained by maintaining the aerobic state or the anaerobic state flexibly according to the water quality and the amount of inflow water, FIG.
In addition to FIG. 2 and the anaerobic-anoxic-aerobic method, the UCT method and the anaerobic-anoxic-aerobic-second denitrification-re-aeration method, an aerobic tank and an aerobic tank or an aerobic tank and anoxic The effect is obtained in all systems where tanks are connected.
【0052】本発明において中間槽を好気条件で運転す
る方法としては反応槽に酸素供給装置を設置する。酸素
供給方法としてはジェットエアレータ等のエアレータを
用いる方法、散気板、ディフューザ等を反応槽内に設置
し、これらを通して酸素含有ガスを反応槽内に吹き込む
方法などがある。In the present invention, as a method of operating the intermediate tank under aerobic conditions, an oxygen supply device is installed in the reaction tank. Examples of the oxygen supply method include a method using an aerator such as a jet aerator, a method in which a diffuser plate, a diffuser, and the like are installed in a reaction tank, and an oxygen-containing gas is blown into the reaction tank through these.
【0053】次に、無酸素条件で反応槽内を撹拌する方
法としては、反応槽内部に水中撹拌機8を設置する方
法、反応槽上部に撹拌機を設置する方法、反応槽内部循
環用ポンプ設置する方法、反応槽上部空間を密閉構造と
し、反応槽に反応槽上部空間に存在する気体を繰り返し
吹き込む方法等がある。Next, as a method of stirring the inside of the reaction tank under oxygen-free conditions, a method of installing a submersible stirrer 8 inside the reaction tank, a method of installing a stirrer above the reaction tank, a pump for circulating the inside of the reaction tank, There is a method of installing, a method of making the upper space of the reaction tank a closed structure, and repeatedly blowing gas existing in the upper space of the reaction tank into the reaction tank.
【0054】また、反応槽内に粗大径の気泡が発生する
散気装置5を設置し、この散気装置に空気を吹き込むこ
とによって反応槽内を撹拌することもできる。この方法
では、吹き込み空気中の酸素の溶解が問題となるが、散
気装置の気泡発散部の孔径を大として、散気される気泡
の径を大とすること、あるいは(および)散気水深を浅
くすることによって酸素の溶解量を低減し、反応槽内を
脱窒反応が生じる条件に保つこことも可能である。Further, a diffuser 5 for generating bubbles having a large diameter may be provided in the reaction tank, and the inside of the reaction tank may be stirred by blowing air into the diffuser. In this method, although the dissolution of oxygen in the blown air poses a problem, the diameter of bubbles to be diffused should be increased by increasing the pore diameter of the bubble diffusion portion of the diffuser, or (and) the depth of the diffused water. It is also possible to reduce the amount of oxygen dissolved by reducing the depth of the reaction vessel and keep the inside of the reaction tank under conditions that cause a denitrification reaction.
【0055】なお、粗大径の散気装置から空気を吹き込
む方法において、酸素の溶解量を低減させるには吹き込
み空気量を低減すれば良いが、その場合には反応槽内部
の撹拌動力も低減するという問題がある。In the method of blowing air from a large-diameter diffuser, the amount of dissolved oxygen can be reduced by reducing the amount of blown air. In this case, the power for stirring inside the reaction tank is also reduced. There is a problem.
【0056】しかしながら、図3に示したように、反応
槽内の片側あるいは中心部等の一部のみから散気を行う
ことによって、反応槽内を液が上昇する部分と下降する
部分とに分け、反応槽内に旋回流を生じさせることによ
って酸素の溶解量を低減しつつ、反応槽内部に十分な撹
拌流速を得ることができる。However, as shown in FIG. 3, by diffusing air from only one side or the center of the reaction tank, the inside of the reaction tank is divided into a rising part and a falling part. By generating a swirling flow in the reaction vessel, a sufficient stirring flow rate can be obtained inside the reaction vessel while reducing the amount of dissolved oxygen.
【0057】これは、旋回流が生じている場合には、液
の上昇流に同伴される形で気泡が上昇し、気泡自体も液
の流れに対してさらに上向きのスリップ速度を有するた
め、気泡の液中における滞留時間(気液接触時間)が減
少するために酸素溶解効率が低下することと、旋回流方
式の方が全面散気方式より高い撹拌力を有することによ
るものである。This is because when the swirling flow is generated, the bubbles rise in the form accompanied by the rising flow of the liquid, and the bubbles themselves have a further upward slip speed with respect to the flow of the liquid. This is because the residence time in the liquid (gas-liquid contact time) is reduced and the oxygen dissolving efficiency is reduced, and the swirling flow method has a higher stirring power than the full air diffusion method.
【0058】また、図4のように、ドラフトチューブや
仕切り板16を反応槽内部に設置するなどし、空気を吹
き込み、そのエアリフト効果によって反応槽内を液が上
昇する部分と下降する部分とに明確に分離することによ
っても同様の効果が得られる。Further, as shown in FIG. 4, a draft tube or a partition plate 16 is installed inside the reaction tank, and air is blown into the reaction tank so that the liquid rises and falls in the reaction tank due to the air lift effect. A similar effect can be obtained by clear separation.
【0059】さらに、図5及び図6に示すように、反応
槽の底部に凹部17を設け、沈降した汚泥を凹部に集め
た後、凹部からエアリフト効果を利用して底部に沈降し
た汚泥を反応槽上部に移送することによって、より底部
への汚泥の沈積のない反応槽内の撹拌が可能である。Further, as shown in FIGS. 5 and 6, a concave portion 17 is provided at the bottom of the reaction tank, and the settled sludge is collected in the concave portion. By transferring to the upper part of the tank, it is possible to stir the inside of the reaction tank without depositing sludge on the bottom part.
【0060】ドラフトチューブや仕切り板を反応槽内に
設置するに当たっては、複数のドラフトチューブや仕切
り板を反応槽内に設置することによって反応槽内を細か
く区分することも可能である。In installing the draft tubes and the partition plates in the reaction tank, it is possible to finely divide the inside of the reaction tank by installing a plurality of draft tubes and partition plates in the reaction tank.
【0061】さらに、粗大径の散気装置15から空気を
吹き込む方法においては、曝気を間欠的に行うことも効
果がある。これは間欠曝気によって、さらに酸素の反応
槽内への溶解量を低減でき、かつ間欠曝気方式において
も十分な反応槽内の撹拌が可能であるためである。Furthermore, in the method of blowing air from the diffuser 15 having a large diameter, intermittent aeration is also effective. This is because the amount of oxygen dissolved in the reaction tank can be further reduced by intermittent aeration, and sufficient stirring in the reaction tank is possible even in the intermittent aeration method.
【0062】間欠曝気の周期の設定については、反応槽
の嫌気度と撹拌状態によって決められ、経験値から周期
を決定することも可能であるが、溶存酸素(DO)計、
酸化還元電位(ORP)計、汚泥濃度計および汚泥界面
計等を利用して自動制御することもできる。The setting of the intermittent aeration cycle is determined by the anaerobic degree and the stirring state of the reaction tank, and it is possible to determine the cycle from empirical values.
Automatic control can also be performed using an oxidation-reduction potential (ORP) meter, a sludge concentration meter, a sludge interface meter, or the like.
【0063】なお、上述の散気による撹拌方式すべてに
共通する事項として、散気装置の水深を浅くすることに
よって、酸素の溶解量を低減することが可能である。ま
た、上述の散気による撹拌方式すべてに共通する事項と
して、生物学的脱窒反応は、液側に若干の溶存酸素が存
在しても反応が進行することが知られており、脱窒反応
を進行させるために反応槽内を完全に無酸素状態にする
必要はない。目安としては、反応槽内の溶存酸素濃度
(DO)を0.5(g/m3 )程度以下とすればよい。Incidentally, as a matter common to all of the above-mentioned agitation methods using aeration, it is possible to reduce the amount of dissolved oxygen by making the water depth of the aeration device shallow. In addition, as a matter common to all the above-described agitation methods using aeration, it is known that the biological denitrification reaction proceeds even if there is some dissolved oxygen on the liquid side. It is not necessary to make the inside of the reaction tank completely oxygen-free in order to advance the reaction. As a guide, the dissolved oxygen concentration (DO) in the reaction tank may be set to about 0.5 (g / m 3 ) or less.
【0064】また、中間槽の上部空間を密閉構造とし
て、上部空間に存在する気体を繰り返し反応槽に吹き込
むことによっても無酸素状態での撹拌が可能である。こ
の場合、初期においては反応槽上部に酸素ガスが存在し
ていても、酸素ガスは液側に溶解して、ガス中の酸素濃
度は徐々に低下するため無酸素条件が確保される。ま
た、上部空間へは、溶解した量に相当する体積分の空気
を補充すればよい。なお、上述のように若干のDOが存
在しても脱窒反応は進行するため、上部空間の密閉度は
完全である必要はない。The oxygen-free agitation can also be achieved by making the upper space of the intermediate tank a closed structure and repeatedly blowing gas present in the upper space into the reaction tank. In this case, even if oxygen gas is present in the upper part of the reaction tank in the initial stage, the oxygen gas dissolves in the liquid side, and the oxygen concentration in the gas gradually decreases, so that the oxygen-free condition is ensured. In addition, the upper space may be supplemented with a volume of air corresponding to the dissolved amount. As described above, the denitrification reaction proceeds even if a small amount of DO is present, so that the airtightness of the upper space does not need to be perfect.
【0065】本発明で設けた無酸素槽と硝化槽の間に設
置される中間反応槽は好気条件で運転するか、あるいは
無酸素条件で運転するかは、流入水および処理水の水質
をモニターして決定することができる。The intermediate reaction tank provided between the oxygen-free tank and the nitrification tank provided in the present invention is operated under aerobic conditions or under oxygen-free conditions depending on the quality of the inflow water and the treated water. You can monitor and decide.
【0066】一般的には、硝化槽流出液にアンモニア性
窒素が残留する場合には、中間反応槽は好気条件で運転
し、無酸素槽流出液にNOX −Nが残留する場合には無
酸素条件で運転を行う。また、アンモニア性窒素やNO
X −Nの測定装置、DO計、ORP計等を利用して自動
制御を行うことも可能である。In general, when ammonia nitrogen remains in the nitrification tank effluent, the intermediate reaction tank is operated under aerobic conditions, and when NO X -N remains in the oxygen-free tank effluent, Operate under anoxic conditions. In addition, ammonia nitrogen or NO
It is also possible to perform automatic control using an X- N measuring device, DO meter, ORP meter and the like.
【0067】さらに、本発明は、硝化槽に微生物固定化
担体を投入したシステムにおいても効果があり、中間反
応槽を好気条件で運転する場合には、BOD成分が中間
反応槽中で浮遊汚泥によって除去されるため、微生物固
定化担体の表面では硝化反応が主として起こり、微生物
固定化担体に硝化細菌を中心とする生物膜が形成され、
硝化の高速化と安定化が達成されるというメリツトが生
ずる。Furthermore, the present invention is also effective in a system in which a microorganism-immobilized carrier is charged into a nitrification tank. When the intermediate reaction tank is operated under aerobic conditions, the BOD component is suspended in the intermediate reaction tank. Due to the removal, the nitrification reaction mainly occurs on the surface of the microorganism-immobilized carrier, a biofilm mainly formed of nitrifying bacteria is formed on the microorganism-immobilized carrier,
There is an advantage that nitrification can be speeded up and stabilized.
【0068】さらに、複数の中間槽を設けることによっ
て、より細かい制御を行うことが可能となり、より大き
な処理水質の向上が達成される。また、反応槽の水深は
5m程度が一般的であるが、深層曝気方式とよばれるよ
うな水深10mから20m程度の曝気槽においても可能
であり、同様の効果が得られる。Further, by providing a plurality of intermediate tanks, finer control can be performed, and a greater improvement in treated water quality can be achieved. The water depth of the reaction tank is generally about 5 m. However, the same effect can be obtained in an aeration tank having a water depth of about 10 m to about 20 m, which is called a deep aeration method.
【0069】以上に示したように、本法では従来法と比
較して、流入水の水量および水質の変動に対してより安
易した高い窒素除去率が達成され、さらにメタノールを
添加する場合においてはメタノールの添加量を大幅に低
減することができる。As described above, compared to the conventional method, the present method achieves a high nitrogen removal rate that is easier with respect to fluctuations in the amount and quality of the influent water. The amount of methanol added can be significantly reduced.
【0070】[0070]
【実施例】以下に本発明の一実施例を説明する。実施例
1は、図1に示した本法を適用した循環型硝化脱窒法の
処理システムと、従来法である循環型硝化脱窒法の処理
システム(図1のフローで中間反応槽を取り除いたフロ
ー)との並列比較実験を行ったものであり、実験条件及
び実験結果は表1に示した通りである。An embodiment of the present invention will be described below. In Example 1, the treatment system of the circulating nitrification and denitrification method to which the present method shown in FIG. 1 is applied and the treatment system of the circulating nitrification and denitrification method which is a conventional method (the flow chart of FIG. 1 from which the intermediate reaction tank is removed) ) Were performed, and the experimental conditions and experimental results are as shown in Table 1.
【0071】[0071]
【表1】 [Table 1]
【0072】反応槽の総槽容積は表1に示されるように
両者は等しい値となっている。本法ではRUN1におい
ては中間反応槽を好気条件に、RUN2およびRUN3
では中間反応槽を無酸素条件に保っている。As shown in Table 1, the total volume of the reaction tanks is equal to each other. In this method, in RUN1, the intermediate reaction tank is placed under aerobic conditions, and RUN2 and RUN3 are run.
, The intermediate reaction tank is maintained in an oxygen-free condition.
【0073】実験結果をみると、RUN1の用にBOD
成分の濃度が高い場合には、高い脱窒速度が得られるた
め、本法と従来法で処理水質に大きな差は見られなかっ
た。これに対して、水温が上昇し流入水のBOD濃度お
よびT−N濃度が低くなったRUN2およびRUN3に
おいては、好気槽を0.9(m3 )としても十分な硝化
反応がは進行していた。Looking at the experimental results, it was found that BOD was used for RUN1.
When the concentration of the components is high, a high denitrification rate can be obtained, so that there is no significant difference in the treated water quality between the present method and the conventional method. On the other hand, in RUN2 and RUN3 in which the BOD concentration and the TN concentration of the influent water decreased due to the rise in water temperature, a sufficient nitrification reaction proceeded even if the aerobic tank was set to 0.9 (m 3 ). I was
【0074】RUN2およびRUN3においては、流入
水のBOD濃度の低下のために脱窒速度が低下したが、
本法では中間槽を無酸素条件で運転しているため、従来
法と比較して処理水のT−Nは3(g/m3 )程度小さ
い値となっており、本法による処理水質の改善効果は顕
著であった。In RUN2 and RUN3, the denitrification rate decreased due to the decrease in the BOD concentration of the inflow water.
In this method, since the intermediate tank is operated under anoxic condition, the TN of the treated water is about 3 (g / m 3 ) smaller than that of the conventional method. The improvement effect was remarkable.
【0075】また、中間槽を無酸素条件に保つ方法とし
てRUN2では水中撹拌機、RUN3では粗大気泡曝気
装置を用いたが、いずれによっても中間槽のDOを0.
1(g/m3 )以下とすることができ、中間槽は脱窒槽
として利用された。As a method for keeping the intermediate tank in an oxygen-free condition, an underwater stirrer was used for RUN2, and a coarse bubble aerator was used for RUN3.
1 (g / m 3 ) or less, and the intermediate tank was used as a denitrification tank.
【0076】実施例2は、図2に示した本法を適用した
硝化−内生脱窒法の処理システムと、従来法の処理シス
テム(図2の中間反応槽を取り除いたもの)との並列比
較実験を行ったものであり、実験条件および実験結果は
表2に示した通りである。Example 2 is a side-by-side comparison of a nitrification-endogenous denitrification treatment system to which the present method shown in FIG. 2 is applied and a conventional treatment system (with the intermediate reaction tank of FIG. 2 removed). The experiment was performed, and the experimental conditions and results are as shown in Table 2.
【0077】[0077]
【表2】 [Table 2]
【0078】反応槽の総槽容積は表2に示されるように
両者は等しい値となっている。本法ではRUN4におい
ては中間反応槽を好気条件に、RUN5およびRUN6
では中間反応槽を無酸素条件に保っている。As shown in Table 2, the total volume of the reaction tanks is equal to each other. In the present method, in RUN4, the intermediate reaction tank is placed under aerobic conditions, and RUN5 and RUN6
, The intermediate reaction tank is maintained in an oxygen-free condition.
【0079】実験結果を見ると、RUN4では流入水濃
度が比較的高かったため、本法においても100%の硝
化を行うために1.5(m3 )の好気槽容積が必要であ
るため、中間槽は好気条件で運転されており、本法と従
来法の好気条件となる反応槽の総槽容積が等しいため、
本法と従来法では処理水質に大きな差は見られなかっ
た。According to the experimental results, since the inflow water concentration was relatively high in RUN4, an aerobic tank volume of 1.5 (m 3 ) was required to perform 100% nitrification even in this method. Since the intermediate tank is operated under aerobic conditions, and the total tank volume of the reaction tank under the aerobic conditions of the present method and the conventional method is equal,
There was no significant difference in the treated water quality between this method and the conventional method.
【0080】これに対して、流入水質が低下したRUN
5およびRUN6では,好気槽容積を1.0(m3 )と
してても100%硝化が達成されており、中間槽は無酸
素槽として利用した。On the other hand, the RUN in which the quality of
In No. 5 and RUN 6, 100% nitrification was achieved even when the volume of the aerobic tank was 1.0 (m 3 ), and the intermediate tank was used as an oxygen-free tank.
【0081】このため、本法では従来法より無酸素槽容
積が17%程度増大しており、メタノール添加量を同一
としたRUN5では、本法の処理水のT−Nは従来法に
比べて1.1(g/m3 )程度改善されていた。For this reason, in the present method, the capacity of the anoxic tank is increased by about 17% compared to the conventional method, and in RUN5 with the same amount of methanol added, the TN of the treated water of the present method is higher than that of the conventional method. It was improved by about 1.1 (g / m 3 ).
【0082】さらに、本法のメタノール添加量を従来法
の同添加量の3分の1としたRUN6においても本法と
従来法の処理水のT−N値は同等であり、処理水質を同
等とする条件では、メタノールの使用量の削減効果、言
い換えれば処理費用の低減効果が得られることが実験的
にも確認された。Further, in RUN 6 in which the amount of methanol added in the present method was one third of the same amount in the conventional method, the TN values of the treated water of the present method and the conventional method were equivalent, and the treated water quality was equivalent. It was also experimentally confirmed that under the conditions described above, the effect of reducing the amount of methanol used, in other words, the effect of reducing the processing cost, was obtained.
【0083】なお、本実験では好気槽、無酸素槽の容積
は表1および表2に記載した値で行ったが、実施設での
反応槽容積は流入水の水質や、要求される処理水水質、
施設面積の制限などを考慮して決定される。In this experiment, the volumes of the aerobic tank and the anoxic tank were set at the values shown in Tables 1 and 2. However, the volume of the reaction tank in the actual installation was determined by the quality of the inflow water and the required treatment. Water quality,
It is determined in consideration of the facility area limit.
【0084】[0084]
【発明の効果】以上のように、本発明によれば、無酸素
槽と好気槽あるいは好気槽と無酸素槽の中間に、好気条
件および無酸素条件のいずれの条件にも設定可能な中間
槽を設け、流入水質および処理水質などに応じて中間槽
の運転条件を適切に切り替えることができるようにした
ため、安定して良好な処理水質を確保できるという効果
が得られる。As described above, according to the present invention, it is possible to set any of the aerobic condition and the anaerobic condition between the anaerobic tank and the aerobic tank or between the aerobic tank and the anaerobic tank. Since an intermediate tank is provided so that the operating conditions of the intermediate tank can be appropriately switched according to the quality of the inflow water and the quality of the treated water, the effect of stably ensuring good treated water quality can be obtained.
【0085】また、脱窒の還元剤が不足し、メタノール
等の還元性物質を投入する場合においても、本発明では
脱窒槽の容積を大きくとることができるためメタノール
等の還元性物質の投入量を削減することができる。Also, in the case where a reducing agent for denitrification is insufficient and a reducing substance such as methanol is charged, the capacity of the denitrification tank can be increased in the present invention. Can be reduced.
【図1】本発明の実施の態様の一例を示す概略的フロー
図。FIG. 1 is a schematic flow chart showing an example of an embodiment of the present invention.
【図2】本発明を利用した汚水処理フローの概略図。FIG. 2 is a schematic diagram of a wastewater treatment flow using the present invention.
【図3】粗大気泡吹き込み方式における反応槽構造の一
例。FIG. 3 shows an example of a reaction tank structure in a coarse bubble blowing system.
【図4】粗大気泡吹き込み方式における反応槽構造の一
例。FIG. 4 shows an example of a reaction tank structure in a coarse bubble blowing system.
【図5】粗大気泡吹き込み方式における反応槽構造の一
例。FIG. 5 shows an example of a reaction tank structure in a coarse bubble blowing system.
【図6】粗大気泡吹き込み方式における反応槽構造の一
例。FIG. 6 shows an example of a reaction tank structure in a coarse bubble blowing system.
1…流入水,2…処理水、3…無酸素槽、4…中間槽、
5…散気装置、6…好気槽,8…撹拌機、15…粗大気
泡発生装置、16…バッフル板あるいはドラフトチュー
ブ、17…凹部。1 ... inflow water, 2 ... treated water, 3 ... oxygen-free tank, 4 ... intermediate tank,
5: diffuser, 6: aerobic tank, 8: stirrer, 15: coarse bubble generator, 16: baffle plate or draft tube, 17: recess.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 澤田 豊志 東京都千代田区丸の内一丁目1番2号 日 本鋼管株式会社内 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Toyoshi Sawada 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Inside Nihon Kokan Co., Ltd.
Claims (8)
化することと、無酸素条件下の無酸素槽で生物的に脱窒
することを組合わせて廃水中の窒素系汚濁物資を除去す
る廃水の処理方法において、前記好気槽と無酸素槽の中
間に少なくとも一つの中間反応槽を設け、好気条件と無
酸素条件のいずれの条件においても運転可能とすること
ができることを特徴とする廃水の処理方法。1. A combination of biologically oxidizing in an aerobic tank under aerobic conditions and biologically denitrifying in an anaerobic tank under anoxic conditions to reduce nitrogen-based pollutants in wastewater. In the method for treating wastewater to be removed, at least one intermediate reaction tank is provided between the aerobic tank and the anoxic tank, and can be operated under any of aerobic conditions and anoxic conditions. Wastewater treatment method.
と、無酸素条件下で生物的に脱窒を行う無酸素槽とを有
して、廃水中の窒素系汚濁物資の除去を行う廃水の処理
装置において、前記好気槽と前記無酸素槽の中間に、散
気装置等により行う好気条件と撹拌装置等により行う無
酸素条件のいずれの条件においても運転可能な少なくと
も一つの中間反応槽を設けたことを特徴とする廃水の処
理装置。2. An aerobic tank for biologically oxidizing under aerobic conditions and an anoxic tank for biologically denitrifying under anoxic conditions to remove nitrogen-based pollutants in wastewater. In the wastewater treatment apparatus for removal, at least in the middle of the aerobic tank and the anoxic tank, at least operable under any of aerobic conditions performed by a diffuser or anoxic conditions performed by a stirrer or the like. A wastewater treatment device comprising one intermediate reaction tank.
おいて、前記好気槽が微生物固定化担体を有することを
特徴とする廃水の処理装置。3. An apparatus for treating wastewater according to claim 2, wherein said aerobic tank has a microorganism-immobilized carrier.
水の処理装置において、前記中間反応槽に設けた撹拌装
置が粗大気泡を発生する散気装置であることを特徴とす
る廃水の処理装置。4. The wastewater treatment apparatus according to claim 2, wherein the stirring device provided in the intermediate reaction tank is a diffuser for generating coarse bubbles. Processing equipment.
おいて、前記中間反応槽に槽内の液が上昇する部分と下
降する部分とに区分する、ドラフトチューブやバッフル
板等を設けたことを特徴とする廃水の処理装置。5. The wastewater treatment apparatus according to claim 4, wherein a draft tube, a baffle plate, and the like are provided in the intermediate reaction tank to divide the liquid in the tank into a rising part and a falling part. Waste water treatment apparatus characterized by the above-mentioned.
水の処理装置において、前記中間反応槽の底部の少なく
とも一部を凹形状としたことを特徴とする廃水の処理装
置。6. The wastewater treatment apparatus according to claim 4, wherein at least a part of a bottom of the intermediate reaction tank is concave.
た廃水の処理装置を用い、前記中間反応槽における粗大
気泡を発生させる散気を間欠的に行うことを特徴とする
廃水の処理方法。7. The wastewater treatment apparatus according to claim 4, wherein the diffuser for generating coarse bubbles in the intermediate reaction tank is intermittently performed. Processing method.
た廃水の処理装置において、前記中間反応槽の上部空間
が密閉構造とされ、この槽の上部空間に存在する気体を
繰り返し槽内に吹き込む装置を設けたことを特徴とする
廃水の処理装置。8. The wastewater treatment apparatus according to claim 2, wherein an upper space of the intermediate reaction tank has a closed structure, and a gas existing in the upper space of the tank is repeatedly discharged. An apparatus for treating wastewater, comprising a device for blowing air into the inside.
Priority Applications (1)
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JP25022396A JPH1094796A (en) | 1996-09-20 | 1996-09-20 | Treatment of waste water and device therefor |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP25022396A JPH1094796A (en) | 1996-09-20 | 1996-09-20 | Treatment of waste water and device therefor |
Publications (1)
Publication Number | Publication Date |
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JPH1094796A true JPH1094796A (en) | 1998-04-14 |
Family
ID=17204676
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Application Number | Title | Priority Date | Filing Date |
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JP25022396A Pending JPH1094796A (en) | 1996-09-20 | 1996-09-20 | Treatment of waste water and device therefor |
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Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2007326075A (en) * | 2006-06-09 | 2007-12-20 | Sharp Corp | Waste water treatment method and waste water treatment equipment |
JP2010264435A (en) * | 2009-05-15 | 2010-11-25 | Shenzhen Jdl Environmental Protection Ltd | Method of forming facultative organism-adapted membrane bioreactor |
JP2011110501A (en) * | 2009-11-27 | 2011-06-09 | Hitachi Ltd | Water treatment equipment |
JP2013212490A (en) * | 2011-11-08 | 2013-10-17 | Toshiba Corp | Nitrogen/phosphor removal treatment method and nitrogen/phosphor removal treatment apparatus |
JP2015024369A (en) * | 2013-07-26 | 2015-02-05 | 株式会社クボタ | Aerobic-cum-anaerobic reaction tank and operation method of the same |
-
1996
- 1996-09-20 JP JP25022396A patent/JPH1094796A/en active Pending
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2007326075A (en) * | 2006-06-09 | 2007-12-20 | Sharp Corp | Waste water treatment method and waste water treatment equipment |
JP2010264435A (en) * | 2009-05-15 | 2010-11-25 | Shenzhen Jdl Environmental Protection Ltd | Method of forming facultative organism-adapted membrane bioreactor |
JP2011110501A (en) * | 2009-11-27 | 2011-06-09 | Hitachi Ltd | Water treatment equipment |
JP2013212490A (en) * | 2011-11-08 | 2013-10-17 | Toshiba Corp | Nitrogen/phosphor removal treatment method and nitrogen/phosphor removal treatment apparatus |
JP2015024369A (en) * | 2013-07-26 | 2015-02-05 | 株式会社クボタ | Aerobic-cum-anaerobic reaction tank and operation method of the same |
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