JP2003136092A - Method and apparatus for treating exhaust gas desulfurization wastewater - Google Patents
Method and apparatus for treating exhaust gas desulfurization wastewaterInfo
- Publication number
- JP2003136092A JP2003136092A JP2001337267A JP2001337267A JP2003136092A JP 2003136092 A JP2003136092 A JP 2003136092A JP 2001337267 A JP2001337267 A JP 2001337267A JP 2001337267 A JP2001337267 A JP 2001337267A JP 2003136092 A JP2003136092 A JP 2003136092A
- Authority
- JP
- Japan
- Prior art keywords
- wastewater
- toxic substance
- activated carbon
- gas desulfurization
- nitrification
- 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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- Purification Treatments By Anaerobic Or Anaerobic And Aerobic Bacteria Or Animals (AREA)
- Water Treatment By Sorption (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、排煙脱硫排水の処理方
法に関する。詳細には、本発明は、バイオセンサを用い
て排水中の毒性物質を連続的に検知することを特徴とす
る排煙脱硫排水の処理方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating flue gas desulfurization wastewater. More specifically, the present invention relates to a method for treating flue gas desulfurization wastewater, which is characterized by continuously detecting toxic substances in wastewater using a biosensor.
【0002】[0002]
【従来技術】スート混合方式排煙脱硫装置から排出され
る排水には、アンモニア性窒素化合物が大量に含有され
ているため、微生物によりかかるアンモニア性窒素化合
物硝化脱窒処理し、窒素にまで分解して除去する処理方
法が知られている。2. Description of the Related Art Wastewater discharged from a soot mixing type flue gas desulfurization device contains a large amount of ammoniacal nitrogen compounds. Therefore, the ammoniacal nitrogen compounds are nitrified and denitrified by microorganisms and decomposed into nitrogen. There is known a processing method of removing by removing.
【0003】しかし、このような排水中には、アンモニ
ア性窒素化合物に加えて、過硫酸(ペルオキソ硫酸S2
O8 2-)、COD物質等が含まれている。COD物質と
は、水中に含まれる化学物質であって、酸化されて水の
汚染の原因になる物質をいう。これらの物質のうち、過
硫酸は強力な酸化剤であるため、微生物の作用によるア
ンモニア性窒素化合物の硝化脱窒工程において微生物に
毒性を与えたり、COD吸着樹脂を劣化させたりすると
いった問題があり、排水処理における阻害要因となって
いる。従って、過硫酸をあらかじめ除去しておく必要が
ある。However, in such waste water, in addition to the ammoniacal nitrogen compound, persulfuric acid (peroxosulfate S 2
O 8 2- ), COD substances, etc. are included. The COD substance is a chemical substance contained in water and is a substance that is oxidized and causes pollution of water. Among these substances, persulfuric acid is a strong oxidant, so there is a problem that it poisons the microorganisms in the nitrifying and denitrifying process of ammoniacal nitrogen compounds by the action of the microorganisms and deteriorates the COD adsorption resin. , Is an obstacle to wastewater treatment. Therefore, it is necessary to remove persulfuric acid in advance.
【0004】また、このような排水中の過硫酸の濃度
は、排煙脱硫装置の運転条件に応じて変化することが多
い。例えば、排煙脱硫装置のスタートアップ時やシャッ
トダウン時には過硫酸濃度が高いが、通常運転時には低
いといったことがある。このような場合、連続的に排水
中の過硫酸を監視し、運転条件の変化に応じ、過硫酸が
存在する場合には効率的に除去することができるように
処理工程を自在に変更させることが必要となる。The concentration of persulfuric acid in the waste water often changes according to the operating conditions of the flue gas desulfurization device. For example, the concentration of persulfuric acid may be high during startup or shutdown of the flue gas desulfurization device, but low during normal operation. In such a case, the persulfuric acid in the wastewater should be continuously monitored, and the treatment process can be freely changed according to changes in operating conditions so that the persulfuric acid can be efficiently removed if it exists. Is required.
【0005】他方、上水道、下水道、及び発酵、食品プ
ロセスなどの分野では、有害化学物質の流入に対する監
視対策として、近年、バイオセンサが注目されてきてい
る(田中良春、田中宏明著、「用水と排水」Vol 40, N
o.4, pp.306-309 (1998)参照)。バイオセンサは、試験
水中に微生物を生育させてその活動状態、例えば溶存酸
素の消費量の変化から毒性物質の存在を検知するもので
ある。特開平6-222041号公報、特開平7-63725号公報、
特公平7-85072号公報、特開平9-89839号公報には、それ
ぞれ、水道水中のフェノール、シアン化カリウム、トリ
クロロエチレンなどの毒性物質を検知するバイオセンサ
が開示されている。On the other hand, in the fields of water supply, sewerage, fermentation, food processing, etc., biosensors have been drawing attention in recent years as monitoring measures against inflow of harmful chemical substances (Yoshiharu Tanaka, Hiroaki Tanaka, "Water and Drainage "Vol 40, N
o.4, pp.306-309 (1998)). The biosensor detects the presence of a toxic substance by growing a microorganism in test water and detecting its activity state, for example, a change in consumption of dissolved oxygen. JP 6-222041 JP, JP 7-63725 JP,
Japanese Patent Publication No. 7-85072 and Japanese Unexamined Patent Publication No. 9-89839 disclose biosensors for detecting toxic substances such as phenol, potassium cyanide, and trichlorethylene in tap water.
【0006】[0006]
【発明が解決しようとする課題】本発明は、排煙脱硫排
水中に含まれる毒性物質、特に過硫酸の濃度を検知し、
その結果に応じて排水の処理工程を変化させて、微生物
による排水の硝化脱窒処理を効率的に行うための方法及
び装置を提供することを目的とする。SUMMARY OF THE INVENTION The present invention detects the concentration of toxic substances, especially persulfuric acid, contained in flue gas desulfurization wastewater,
An object of the present invention is to provide a method and an apparatus for efficiently performing nitrification / denitrification treatment of wastewater by microorganisms by changing the wastewater treatment process according to the result.
【0007】[0007]
【課題を解決するための手段】微生物の代謝を阻害する
毒性物質の存在により変化する溶存酸素濃度を測定する
バイオセンサによって、排煙脱硫排水中の毒性物質を検
知する工程と、該毒性物質又は該排水中に含まれる有機
物を除去する活性炭処理工程と、該排水中のアンモニア
性窒素化合物を分解する硝化脱窒工程とを含み、該バイ
オセンサによる毒性物質の検知結果に応じて、該活性炭
処理工程と該硝化脱窒工程の順序を変えて該排水を処理
することを特徴とする排煙脱硫排水の処理方法を提供す
る。前記毒性物質が過硫酸であり、前記バイオセンサが
微生物の代謝を阻害する毒性物質の存在により変化する
溶存酸素濃度を測定するものであり、該微生物が亜硝酸
菌であることが好ましい。前記バイオセンサで測定され
る溶存酸素濃度変化の値が基準値以上であるときは、前
記硝化脱窒工程後に前記活性炭処理工程を行い、前記溶
存酸素濃度変化の値が基準値以下であるときは、前記活
性炭処理工程後に前記硝化脱窒工程を行うことを特徴と
する排煙脱硫排水の処理方法を提供する。さらに本発明
は、微生物の代謝を阻害する毒性物質の存在により変化
する溶存酸素濃度を測定することにより、排煙脱硫排水
の毒性物質を検知するバイオセンサと、該毒性物質ある
いは該排水中に含まれる有機物を除去する活性炭処理装
置と、該排水中のアンモニア性窒素化合物を分解する硝
化脱窒装置とを備えてなる上述の方法により該排水を処
理するための排煙脱硫排水の処理装置を提供する。前記
活性炭処理装置と前記硝化脱窒装置との間に設けられた
1以上のバルブと、該バルブの開閉を制御する手段とを
さらに備えてなることが好ましい。ここで、前記活性炭
処理装置と前記硝化脱窒装置との間とは、かかる活性炭
処理装置と硝化脱窒装置とを備えてなる排煙脱硫排水の
処理装置内に存在するあらゆる連結の間が含まれ、直接
に活性炭処理装置と硝化脱窒装置との間に限定されるも
のではない。[Means for Solving the Problems] A step of detecting a toxic substance in flue gas desulfurization effluent by a biosensor for measuring a dissolved oxygen concentration which changes due to the presence of a toxic substance that inhibits microbial metabolism, and the toxic substance or An activated carbon treatment step of removing organic matter contained in the wastewater, and a nitrification denitrification step of decomposing ammoniacal nitrogen compounds in the wastewater are included, and the activated carbon treatment is carried out according to the detection result of the toxic substance by the biosensor. Provided is a method for treating flue gas desulfurization wastewater, which comprises treating the wastewater by changing the order of the steps and the nitrification / denitrification step. It is preferable that the toxic substance is persulfuric acid, the biosensor measures a dissolved oxygen concentration that changes due to the presence of a toxic substance that inhibits metabolism of a microorganism, and the microorganism is a nitrite. When the value of the dissolved oxygen concentration change measured by the biosensor is equal to or higher than the reference value, the activated carbon treatment step is performed after the nitrification denitrification step, and when the value of the dissolved oxygen concentration change is equal to or lower than the reference value. Provided is a method for treating flue gas desulfurization wastewater, which comprises performing the nitrification denitrification step after the activated carbon treatment step. Furthermore, the present invention includes a biosensor for detecting a toxic substance in flue gas desulfurization wastewater by measuring a dissolved oxygen concentration which changes due to the presence of a toxic substance that inhibits metabolism of a microorganism, and a biosensor included in the toxic substance or the wastewater. Provided is a flue gas desulfurization wastewater treatment apparatus for treating the wastewater by the above-mentioned method, which comprises an activated carbon treatment apparatus for removing organic matter and a nitrification denitrification apparatus for decomposing ammoniacal nitrogen compounds in the wastewater. To do. It is preferable that the apparatus further comprises one or more valves provided between the activated carbon treatment apparatus and the nitrification / denitrification apparatus, and means for controlling opening / closing of the valves. Here, the term "between the activated carbon treatment device and the nitrification denitrification device" includes any connection existing in the treatment device for flue gas desulfurization wastewater comprising the activated carbon treatment device and the nitrification denitrification device. However, it is not limited directly to the activated carbon treatment device and the nitrification denitrification device.
【0008】[0008]
【発明の実施の態様】次に図面を用いて本発明を詳細に
説明する。以下の説明は本発明を限定するものではな
い。BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail with reference to the drawings. The following description does not limit the invention.
【0009】本発明では、亜硝酸菌を用いて過硫酸を検
出するバイオセンサを好適に用いることができる。本発
明者らは、排煙脱硫装置の排水中に含まれる過硫酸が、
硝化菌、特に亜硝酸菌に対し毒性物質として作用するこ
とを見出した。これまでのバイオセンサで検知可能な毒
性物質は、シアン化合物、フェノール、有機塩素化合物
にとどまっており、排煙脱硫排水処理、ことに過硫酸を
毒性物質として検知することに応用されている例はなか
った。In the present invention, a biosensor for detecting persulfate using nitrite can be preferably used. The present inventors have found that the persulfuric acid contained in the wastewater of the flue gas desulfurizer is
It was found that it acts as a toxic substance against nitrifying bacteria, especially nitrite bacteria. So far, the only toxic substances that can be detected by biosensors are cyan compounds, phenols, and organic chlorine compounds, and examples of application to flue gas desulfurization wastewater treatment, especially persulfuric acid detection as a toxic substance are given below. There wasn't.
【0010】亜硝酸菌は阻害物質が含まれていない場合
は、呼吸によって、水中の溶存酸素を一定の速度で消費
し、アンモニア性窒素化合物を亜硝酸塩に変換すること
が知られている。しかし、排水中に過硫酸が含まれてい
ると、亜硝酸菌の代謝活動が阻害されて呼吸速度が鈍
り、排水中の溶存酸素の消費速度が低下する。このた
め、阻害物質が存在するとき、排水中の溶存酸素濃度変
化をバイオセンサで測定すると、阻害物質が存在しない
ときの排水中の溶存酸素濃度変化と比べ小さくなってい
る。It is known that when nitrite bacteria contain no inhibitory substance, they consume dissolved oxygen in water at a constant rate by respiration to convert ammoniacal nitrogen compounds into nitrite. However, if persulfate is contained in the waste water, the metabolic activity of nitrite bacteria is inhibited, the respiratory rate becomes slow, and the consumption rate of dissolved oxygen in the waste water decreases. Therefore, when a change in the dissolved oxygen concentration in the wastewater when the inhibitor is present is measured by a biosensor, it is smaller than the change in the dissolved oxygen concentration in the wastewater when the inhibitor is not present.
【0011】従って、本発明ではバイオセンサを用い
て、次のようにして阻害物質の存在を検知する。亜硝酸
菌の固定化微生物膜に、排水の一部を通過させて溶存酸
素濃度の変化の値を測定する。ここで、亜硝酸菌の酸素
消費速度に比例する溶存酸素濃度変化の値が基準値以上
のときは亜硝酸菌の代謝阻害が小さく、試験排水には活
性炭処理を必要とする程の阻害物質が含まれていないこ
とがわかる。基準値とは、微生物の生息状況や排水温度
等の運転条件により適宜定められる、阻害物質の有無を
判断する基準となる値である。一方、阻害物質が存在す
ると、亜硝酸菌の酸素消費速度が大幅に減少するため、
溶存酸素濃度の変化の値は小さくなり、阻害物質の存在
の検知が可能となる。Therefore, in the present invention, a biosensor is used to detect the presence of an inhibitor as follows. A part of the wastewater is passed through an immobilized microbial membrane of nitrite to measure the change in dissolved oxygen concentration. Here, when the value of the change in dissolved oxygen concentration proportional to the oxygen consumption rate of nitrite is greater than or equal to the reference value, the inhibition of metabolism of nitrite is small, and the test effluent contains an inhibitor such that activated carbon treatment is required. You can see that it is not included. The reference value is a value that is appropriately determined depending on operating conditions such as habitation of microorganisms and drainage temperature, and is a reference value for determining the presence or absence of an inhibitor. On the other hand, the presence of inhibitors significantly reduces the oxygen consumption rate of nitrite bacteria,
The value of the change in the dissolved oxygen concentration becomes small, and it becomes possible to detect the presence of the inhibitor.
【0012】このようなバイオセンサは、亜硝酸菌を多
孔性膜などのマトリクスに固定した固定化微生物膜と、
適切な溶存酸素電極などを用い、公知技術を利用して作
製することができる。亜硝酸菌は、アンモニア性窒素化
合物を代謝により酸化して、亜硝酸性窒素化合物にまで
変換する性質を有する微生物であり、その反応は次式で
表される。Such a biosensor comprises an immobilized microbial membrane in which nitrite bacteria are immobilized on a matrix such as a porous membrane,
It can be produced using a known technique using an appropriate dissolved oxygen electrode or the like. Nitrite bacteria are microorganisms that have the property of oxidizing ammoniacal nitrogen compounds by metabolism to convert them into nitrite nitrogen compounds, and the reaction is represented by the following formula.
【化1】 [Chemical 1]
【0013】亜硝酸菌には、学名、ニトロソモナス・ユ
ーロピアなどがあるが、本発明は、これに限定されるも
のではない。特に、本発明のバイオセンサでは、公知の
固定化微生物膜式のものを使用することが好ましい。The nitrite bacteria have scientific names such as Nitrosomonas europia, but the present invention is not limited thereto. In particular, in the biosensor of the present invention, it is preferable to use a known immobilized microbial membrane type sensor.
【0014】本発明によれば、バイオセンサによる毒性
物質の検知結果に応じ、後続の処理工程を変化させるこ
とができる。図1に、バイオセンサを用いた本発明の排
煙脱硫排水の処理装置8を示して、全体の工程を説明す
る。前処理装置2において、排煙脱硫装置から排出され
るアンモニア性窒素化合物を含む脱硫排水1中のフッ素
やカルシウム化合物などが除去される。これらを除去さ
れた排水のごく一部が、次にバイオセンサ3に導入され
る。バイオセンサ3で、微生物の代謝により変化する溶
存酸素濃度を測定することにより、当該排水中の毒性物
質の有無を検知する。According to the present invention, subsequent processing steps can be changed according to the detection result of the toxic substance by the biosensor. FIG. 1 shows a flue gas desulfurization wastewater treatment apparatus 8 of the present invention using a biosensor, and the overall steps will be described. In the pretreatment device 2, fluorine, calcium compounds, etc. in the desulfurization effluent 1 containing the ammoniacal nitrogen compound discharged from the flue gas desulfurization device are removed. A small part of the wastewater from which these have been removed is then introduced into the biosensor 3. The presence / absence of a toxic substance in the wastewater is detected by measuring the dissolved oxygen concentration, which changes due to the metabolism of microorganisms, with the biosensor 3.
【0015】バイオセンサ3により毒性物質が検知され
た場合は、例えば変換器など、バルブの制御手段4によ
り、バルブの開閉が表1の「切替時」に記載のように制
御される。毒性物質が検知されると、バルブ11は閉ま
り、バルブ12が開いて、前処理装置2を経た排水は、
活性炭処理装置6に導入され、ここで毒性物質である過
硫酸が活性炭触媒等により分解除去される。活性炭処理
工程を経て過硫酸を除去された排水は、バルブ14およ
びバルブ15が閉じられ、バルブ13が開いているた
め、硝化脱窒装置5で、含有するアンモニア性窒素化合
物が分解処理されて、処理済水7は、本発明の装置の系
外へ放出される。When a toxic substance is detected by the biosensor 3, the valve control means 4 such as a converter controls the opening and closing of the valve as described in "at the time of switching" in Table 1. When a toxic substance is detected, the valve 11 is closed, the valve 12 is opened, and the wastewater passing through the pretreatment device 2 is
It is introduced into the activated carbon treatment device 6, where persulfuric acid which is a toxic substance is decomposed and removed by an activated carbon catalyst or the like. The wastewater from which the persulfuric acid has been removed through the activated carbon treatment step has the valve 14 and the valve 15 closed and the valve 13 open, so that the nitrifying and denitrifying device 5 decomposes the contained ammoniacal nitrogen compound, The treated water 7 is discharged out of the system of the device of the present invention.
【0016】[0016]
【表1】 [Table 1]
【0017】一方、バイオセンサ3により毒性物質が検
知されなかった場合は、バルブの制御手段4により、活
性炭処理装置6と硝化脱窒装置5との間に設けられたバ
ルブの開閉が表1に示す「通常時」のように制御され
る。このとき、バルブ11が開いて、バルブ12は閉じ
られており、前処理装置2を経た排水は、硝化脱窒装置
5において、微生物の作用によりアンモニア性窒素化合
物が分解される。含有するアンモニア性窒素化合物が分
解除去された排水は、バルブ14が開いて、バルブ16
が閉まっているため、活性炭処理装置6に導入され、活
性炭処理により工業用水由来の残留している有機物等が
除去される。このとき、硝化脱窒装置5の後続に活性炭
処理装置6を設置するのは、硝化脱窒工程においても、
かかる工業用水由来の有機物等が若干分解されるので、
後続の活性炭処理工程での活性炭の吸着力の低下を防止
することができるといった理由からである。活性炭処理
装置を経た排水は、バルブ13が閉まっており、バルブ
15が開いているため、処理済水7として系外へ放出さ
れる。ここで、図1に示す排煙脱硫排水の処理装置8に
おけるバルブの配置及び数は、例示であって、本発明は
かかる形態に限定されるものではない。On the other hand, when no toxic substance is detected by the biosensor 3, the valve control means 4 opens and closes the valve provided between the activated carbon treatment device 6 and the nitrification denitrification device 5 in Table 1. It is controlled as shown in "normal time". At this time, the valve 11 is opened and the valve 12 is closed, and the wastewater that has passed through the pretreatment device 2 is decomposed into ammoniacal nitrogen compounds by the action of microorganisms in the nitrification denitrification device 5. The wastewater from which the contained ammoniacal nitrogen compound has been decomposed and removed opens the valve 14 and opens the valve 16
Since it is closed, it is introduced into the activated carbon treatment device 6 and residual organic substances derived from industrial water are removed by the activated carbon treatment. At this time, the activated carbon treatment device 6 is installed after the nitrification denitrification device 5 even in the nitrification denitrification process.
Since organic matter derived from such industrial water is slightly decomposed,
This is because it is possible to prevent the adsorption force of activated carbon from being lowered in the subsequent activated carbon treatment step. Since the valve 13 is closed and the valve 15 is opened, the wastewater that has passed through the activated carbon treatment device is discharged outside the system as treated water 7. Here, the arrangement and number of valves in the flue gas desulfurization wastewater treatment apparatus 8 shown in FIG. 1 are merely examples, and the present invention is not limited to such an embodiment.
【0018】このように、バイオセンサ3によって微生
物代謝の阻害物質を検知し、その結果に応じて、その後
の処理工程を制御することができるのが本発明の特長と
するところである。制御は、バイオセンサ3に連結され
た交換器などの制御手段4によって、処理装置間に設け
られたバルブを開閉し、処理工程の順序を変えることに
よって行うことができる。ここで、処理装置間とは、排
煙脱硫排水の処理装置8に含まれる硝化脱窒装置5や活
性炭処理装置6など個々の装置間をいうが、特定の装置
間を直接に連結するもののみには限定されない。図1に
示すバルブ11〜16のように、処理を受ける排水の処
理工程の順序を変えることを目的として設けられるあら
ゆるバルブを含む。以下に、阻害物質の有無に応じて排
水が処理を受ける工程を詳細に説明する。As described above, it is a feature of the present invention that the biosensor 3 can detect an inhibitor of microbial metabolism, and the subsequent processing steps can be controlled according to the result. The control can be performed by changing the order of processing steps by opening and closing valves provided between the processing devices by the control means 4 such as an exchanger connected to the biosensor 3. Here, the term “between treatment devices” refers to individual devices such as the nitrification denitrification device 5 and the activated carbon treatment device 6 included in the flue gas desulfurization wastewater treatment device 8, but only those that directly connect specific devices. It is not limited to The valves 11 to 16 shown in FIG. 1 include all valves provided for the purpose of changing the order of the treatment process of wastewater to be treated. The process of treating wastewater according to the presence or absence of an inhibitor will be described in detail below.
【0019】[過硫酸が検出された場合]バイオセンサ
3で測定した試料水中の溶存酸素濃度変化の値が基準値
以下であるときには、過硫酸が存在することを示す。こ
のとき、前処理工程2を経た排水は、過硫酸を除去する
ために活性炭処理装置6に導入される。活性炭処理装置
6において、過硫酸は、触媒を用いて以下の式で表され
る分解反応により分解され、除去される。[When Persulfate is Detected] When the change in the dissolved oxygen concentration in the sample water measured by the biosensor 3 is less than the reference value, it indicates that persulfate is present. At this time, the wastewater that has passed through the pretreatment step 2 is introduced into the activated carbon treatment device 6 in order to remove the persulfuric acid. In the activated carbon treatment device 6, persulfuric acid is decomposed and removed by a decomposition reaction represented by the following formula using a catalyst.
【0020】[0020]
【化2】 [Chemical 2]
【0021】活性炭処理装置6で用いる触媒としては、
活性炭、活性炭や還元剤等を担持させたセラミックス等
が好ましく用いられる。本発明は、これに限定されるも
のではないが、過硫酸の分解を触媒する機能と、排水中
に存在する有機物等を吸着除去する機能とが必要とされ
る。活性炭を用いる場合には、活性炭は、どのような形
状、大きさのものでも使用することができるが、好まし
くは粒径0.1〜2mm程度の活性炭を用いる。活性炭
吸着は、反応槽における処理または通水接触のどちらの
方法によっても行うことができる。通水接触の場合は、
0.1〜2mm程度の粒状活性炭を充填させた吸着塔
を、SV=1〜20hr-1程度の通水条件で行うのが好
ましい。As the catalyst used in the activated carbon treatment device 6,
Activated carbon, ceramics carrying activated carbon, a reducing agent and the like are preferably used. The present invention is not limited to this, but it is required to have a function of catalyzing the decomposition of persulfuric acid and a function of adsorbing and removing organic substances and the like existing in the wastewater. When activated carbon is used, activated carbon having any shape and size can be used, but activated carbon having a particle size of about 0.1 to 2 mm is preferably used. The activated carbon adsorption can be carried out by either the treatment in the reaction tank or the contact with water. In case of water contact,
It is preferable to carry out the adsorption tower filled with the granular activated carbon of about 0.1 to 2 mm under the water flow condition of SV = 1 to 20 hr −1 .
【0022】活性炭処理装置6を経た排水は、硝化脱窒
装置5に送られる。硝化脱窒装置5では、微生物処理が
行われ、硝化菌や脱窒素菌を用いて最終的に窒素ガスに
まで分解される。硝化菌は、アンモニア性窒素化合物を
硝酸塩にまで酸化する働きをし、これには、(1)式に
示すようにアンモニア性窒素化合物を亜硝酸塩にする亜
硝酸菌、(2)式に示すように亜硝酸塩を硝酸塩にする
硝酸菌がある。このような硝化工程は、水酸化ナトリウ
ムのようなアルカリ剤によりpHを弱アルカリ性、例え
ばpHを約7〜8程度に調整し、好気性条件下で行うの
が望ましい。硝化工程は、例えば、硝酸菌及び亜硝酸菌
を含む活性汚泥を担体に付着させた硝化槽において反応
させることによって達成される。Wastewater that has passed through the activated carbon treatment device 6 is sent to the nitrification and denitrification device 5. In the nitrification / denitrification device 5, microbial treatment is performed, and finally it is decomposed into nitrogen gas by using nitrifying bacteria and denitrifying bacteria. Nitrifying bacteria function to oxidize ammoniacal nitrogen compounds to nitrates, which include nitrite bacteria that convert ammoniacal nitrogen compounds to nitrites as shown in formula (1) and formula (2) as shown in formula (2). There are nitric acid bacteria that turn nitrite into nitrate. It is desirable that such a nitrification step is carried out under aerobic conditions by adjusting the pH to weakly alkaline, for example, about 7 to 8 with an alkaline agent such as sodium hydroxide. The nitrification step is achieved, for example, by reacting in an nitrification tank in which activated sludge containing nitric acid bacteria and nitrite bacteria is attached to a carrier.
【0023】脱窒工程は、脱窒菌により、生じた硝酸ま
たは亜硝酸を還元して、窒素ガスに変える工程である。
脱窒素菌は、以下の(3)式に示すように硝酸塩を窒素
ガスに変換する。The denitrification step is a step of reducing the generated nitric acid or nitrous acid by a denitrifying bacterium and converting it into nitrogen gas.
The denitrifying bacterium converts nitrate into nitrogen gas as shown in the following formula (3).
【化3】 [Chemical 3]
【0024】脱窒工程は、好ましくは、嫌気条件下で行
い、有機炭素源として、メタノール、酢酸、エタノー
ル、グルコース等の純物質の他、他の排水のBODや廃
糖蜜等があげられるが取り扱いや注入設備の簡素化、お
よび運転費用の低廉さから、メタノールが特に好まし
い。脱窒工程は、硝化工程同様に脱窒菌を含む活性汚泥
を担体に付着させた脱窒槽において反応させることによ
り行うことができる。The denitrification step is preferably carried out under anaerobic conditions, and as organic carbon sources, pure substances such as methanol, acetic acid, ethanol and glucose, as well as BOD from other waste water and molasses can be mentioned. Methanol is particularly preferable because of its simple injection equipment and low operating cost. The denitrification step can be carried out by reacting it in a denitrification tank in which activated sludge containing denitrifying bacteria is attached to a carrier as in the nitrification step.
【0025】このような硝化脱窒装置5については、特
開平11-090485号公報や、特開平10-296296号公報などに
詳述されており、かかる従来から用いられている装置を
用いることができるがそれらには限定されない。本発明
では、硝化脱窒装置5に導入される排水は、過硫酸が除
去されている。従って、硝化脱窒装置5において硝化菌
等の微生物の働きが阻害されることはない。Such a nitrification / denitrification apparatus 5 is described in detail in JP-A-11-090485 and JP-A-10-296296, and it is possible to use such a conventionally used apparatus. Yes, but not limited to. In the present invention, the waste water introduced into the nitrification / denitrification device 5 is free from persulfuric acid. Therefore, the functions of microorganisms such as nitrifying bacteria are not hindered in the nitrification / denitrification device 5.
【0026】硝化脱窒装置5を経た排水は、過硫酸、ア
ンモニア性窒素化合物が除去されている処理済水7であ
る。Wastewater that has passed through the nitrification / denitrification device 5 is treated water 7 from which persulfuric acid and ammoniacal nitrogen compounds have been removed.
【0027】[過硫酸が検出されなかった場合]バイオ
センサ3により、試料水中の溶存酸素濃度変化の値が基
準値以上であることが検知されたときは、過硫酸が所定
濃度以上に存在しないことを示す。従って、活性炭処理
装置6による過硫酸分解の工程を経ることなく、排水は
硝化脱窒装置5に導入され、排水中のアンモニア性窒素
化合物は硝化菌や脱窒素菌等の微生物によって分解除去
される。アンモニア性窒素化合物が除去された後の排水
は、過硫酸を除去するために用いたのと同一の活性炭処
理装置6によって排水中に溶存する有機物、例えば排水
の成因である工業用水中にもともと含まれていた有機物
などが除去される。[When Persulfate is not Detected] When the biosensor 3 detects that the value of the change in the dissolved oxygen concentration in the sample water is above the reference value, the persulfate does not exist above the predetermined concentration. Indicates that. Therefore, the wastewater is introduced into the nitrification denitrification device 5 without passing through the step of persulfate decomposition by the activated carbon treatment device 6, and the ammoniacal nitrogen compounds in the wastewater are decomposed and removed by microorganisms such as nitrifying bacteria and denitrifying bacteria. . The wastewater after the removal of the ammoniacal nitrogen compound is originally contained in the organic matter dissolved in the wastewater by the same activated carbon treatment device 6 used for removing the persulfuric acid, for example, industrial water that is the cause of the wastewater. The organic substances that had been removed are removed.
【0028】排水中の過硫酸濃度は、脱硫排煙装置の稼
動状況によって変化する。従って、本発明の装置におい
ては、脱硫排煙装置の稼動中、連続的に過硫酸の濃度を
モニタリングし、必要に応じて処理工程を切替えること
ができるように制御する。これにより、一つの装置で、
排水に含まれる過硫酸の量により異なる有効な排水処理
工程の実現が可能となり、効率的に排水処理を行うこと
ができる。The concentration of persulfuric acid in the waste water changes depending on the operating conditions of the desulfurization smoke exhaust device. Therefore, in the device of the present invention, the concentration of persulfuric acid is continuously monitored during the operation of the desulfurization smoke exhaust device, and the process steps are controlled so that they can be switched as necessary. This allows one device to
It is possible to realize an effective wastewater treatment process that varies depending on the amount of persulfuric acid contained in the wastewater, so that wastewater treatment can be performed efficiently.
【0029】[0029]
【実施例】次に、実施例を挙げて、本発明をさらに詳細
に説明する。実施例は本発明を限定するものではない。EXAMPLES Next, the present invention will be described in more detail with reference to examples. The examples do not limit the invention.
【0030】〔実施例1〕排煙脱硫装置の排水を、本発
明の処理装置および従来型の処理装置で処理し、その結
果を比較した。Example 1 Wastewater of a flue gas desulfurization apparatus was treated by the treatment apparatus of the present invention and a conventional treatment apparatus, and the results were compared.
【0031】過硫酸を含まず、アンモニア性窒素化合物
由来の窒素を100mg/Lの濃度で含む排水を、表1
に示す通常時のバルブ開閉制御条件で処理した。試験条
件は、SV=10L/h、LV=3m/hとした。使用
した活性炭は、三菱化学ダイヤホープである。前処理装
置で処理した後の水について硝化脱窒処理を行い、全窒
素(T−N)を測定した。硝化脱窒処理工程では、微生
物の栄養源として、メタノールを200mg/L(C/
N=2.5)となるように添加した。このときの運転結
果を表2の実施例1に示す。表2中、S2O8は過硫酸イ
オンあるいは過硫酸塩を、NH3−Nはアンモニア性窒
素化合物由来の窒素を、T−Nはアンモニア、亜硝酸
性、硝酸窒素性の各々の化合物由来の窒素量である全窒
素を示す。明らかに、硝化脱窒工程でアンモニア性窒素
化合物由来の窒素が除去されていることがわかった。Waste water containing no persulfuric acid and containing nitrogen derived from an ammoniacal nitrogen compound at a concentration of 100 mg / L is shown in Table 1.
The processing was performed under the normal valve opening / closing control conditions shown in. The test conditions were SV = 10 L / h and LV = 3 m / h. The activated carbon used is Mitsubishi Kagaku Diamond Hope. The water after treated with the pretreatment device was subjected to nitrification denitrification treatment, and total nitrogen (TN) was measured. In the nitrification and denitrification process, 200 mg / L of methanol (C /
N = 2.5) was added. The operation result at this time is shown in Example 1 of Table 2. In Table 2, S 2 O 8 is persulfate ion or persulfate, NH 3 -N is nitrogen derived from ammoniacal nitrogen compound, and TN is ammonia, nitrite-derived, or nitrate-nitrogen-derived compound. The total nitrogen, which is the amount of nitrogen, is shown. Clearly, it was found that the nitrogen derived from the ammoniacal nitrogen compound was removed in the nitrification denitrification step.
【0032】〔実施例2〕次に、過硫酸イオンを100
mg/L、アンモニア性窒素化合物由来の窒素を100
mg/Lの濃度で含む排水を、表1に示す切替時のバル
ブ開閉制御条件で処理した。このときの運転結果を表2
の実施例2に示す。脱硫排水が硝化脱窒工程に流入する
前に活性炭処理工程で過硫酸が完全に除去されていた。
従って、過硫酸が含まれていないため、微生物の代謝阻
害はなく、過硫酸を含まない実施例1の排水と同程度
に、硝化脱窒工程で窒素が除去されていることがわかっ
た。Example 2 Next, 100 persulfate ions were added.
mg / L, 100% nitrogen derived from ammoniacal nitrogen compounds
The wastewater containing at a concentration of mg / L was treated under the valve opening / closing control conditions at the time of switching shown in Table 1. Table 2 shows the operation results at this time.
Example 2 of Persulfuric acid was completely removed in the activated carbon treatment process before the desulfurization wastewater flowed into the nitrification and denitrification process.
Therefore, it was found that, since persulfate was not contained, there was no inhibition of microbial metabolism, and nitrogen was removed in the nitrification and denitrification step to the same extent as the wastewater of Example 1 containing no persulfate.
【0033】〔比較例〕過硫酸を100mg/L、アン
モニア性窒素化合物由来の窒素を100mg/Lの濃度
で含む排水を、過硫酸が検出されているにもかかわら
ず、通常時と同じフローで処理した場合の運転結果を表
2の比較例に示す。この場合、硝化脱窒工程で硝化脱窒
機能が低下し、やがて脱硫排水中のアンモニア性窒素化
合物由来の窒素は全く処理されなくなった。[Comparative Example] Waste water containing 100 mg / L of persulfuric acid and 100 mg / L of nitrogen derived from an ammoniacal nitrogen compound was subjected to the same flow as in the normal state even though persulfuric acid was detected. The operation results when treated are shown in the comparative example of Table 2. In this case, the nitrifying and denitrifying function was deteriorated in the nitrifying and denitrifying step, and eventually the nitrogen derived from the ammoniacal nitrogen compound in the desulfurization wastewater was not treated at all.
【0034】[0034]
【表2】 [Table 2]
【0035】これらの結果から、本発明の排水処理装置
8により、微生物の硝化脱窒反応を阻害する過硫酸をバ
イオセンサ3で検知し予め除去することにより、効率的
に排水の処理を行うことが可能であることがわかった。Based on these results, the wastewater treatment device 8 of the present invention detects the persulfuric acid which inhibits the nitrifying and denitrifying reaction of microorganisms by the biosensor 3 and removes it in advance, thereby efficiently treating the wastewater. It turns out that is possible.
【0036】[0036]
【発明の効果】バイオセンサを用い、予め毒性物質の存
在の有無を確認して工程順序を選択することにより、排
煙脱硫排水中に過硫酸が含まれている場合も確実に検知
し、予め過硫酸を除去した後、微生物の代謝に悪影響を
及ぼすことなく窒素化合物を効率よく処理することがで
きる。また、バルブ操作のみによって工程順序を容易に
変更することができる。これにより、排水性状の変化に
対して、活性炭などの触媒による活性炭処理装置の過硫
酸除去機能と有機物除去機能とを使い分けすることがで
きる。[Effects of the Invention] By using a biosensor to confirm the presence or absence of toxic substances in advance and select the process sequence, it is possible to reliably detect even the case where persulfuric acid is contained in the flue gas desulfurization wastewater. After removing persulfate, nitrogen compounds can be efficiently treated without adversely affecting the metabolism of microorganisms. Further, the process sequence can be easily changed only by operating the valve. This makes it possible to properly use the persulfuric acid removal function and the organic matter removal function of the activated carbon treatment device using a catalyst such as activated carbon, with respect to changes in the drainage property.
【図1】図1は、本発明による排煙脱硫排水の処理装置
の一例を示す図である。FIG. 1 is a diagram showing an example of a flue gas desulfurization wastewater treatment apparatus according to the present invention.
1 脱硫排水 2 前処理装置 3 バイオセンサ 4 制御手段 5 硝化脱窒装置 6 活性炭処理装置 7 処理済水 8 排煙脱硫排水の処理装置 11 バルブ 12 バルブ 13 バルブ 14 バルブ 15 バルブ 16 バルブ 1 desulfurization drainage 2 Pretreatment equipment 3 biosensor 4 Control means 5 Nitrification and denitrification equipment 6 Activated carbon processing equipment 7 treated water 8 Flue gas desulfurization wastewater treatment equipment 11 valves 12 valves 13 valves 14 valves 15 valves 16 valves
───────────────────────────────────────────────────── フロントページの続き Fターム(参考) 4D024 AA04 AB04 BA02 DA03 DA04 DB15 DB16 4D040 BB12 BB22 BB91 BB93 ─────────────────────────────────────────────────── ─── Continued front page F-term (reference) 4D024 AA04 AB04 BA02 DA03 DA04 DB15 DB16 4D040 BB12 BB22 BB91 BB93
Claims (5)
により変化する溶存酸素濃度を測定するバイオセンサに
よって、排煙脱硫排水中の毒性物質を検知する工程と、 該毒性物質又は該排水中に含まれる有機物を除去する活
性炭処理工程と、 該排水中のアンモニア性窒素化合物を分解する硝化脱窒
工程とを含み、 該バイオセンサによる毒性物質の検知結果に応じて、該
活性炭処理工程と該硝化脱窒工程の順序を変えて排水を
処理することを特徴とする排煙脱硫排水の処理方法。1. A step of detecting a toxic substance in flue gas desulfurization effluent by a biosensor for measuring a dissolved oxygen concentration which changes depending on the presence of a toxic substance inhibiting microbial metabolism, and a step of detecting the toxic substance or the effluent in the effluent. The method includes an activated carbon treatment step of removing organic substances contained therein and a nitrification denitrification step of decomposing ammoniacal nitrogen compounds in the wastewater. The activated carbon treatment step and the nitrification step are performed according to the detection result of the toxic substance by the biosensor. A method for treating flue gas desulfurization wastewater, which comprises treating wastewater by changing the order of the denitrification process.
オセンサが微生物の代謝を阻害する毒性物質の存在によ
り変化する溶存酸素濃度を測定するものであり、該微生
物が亜硝酸菌である請求項1に記載の排煙脱硫排水の処
理方法。2. The toxic substance is persulfuric acid, the biosensor measures a dissolved oxygen concentration which changes due to the presence of a toxic substance that inhibits metabolism of a microorganism, and the microorganism is a nitrite. Item 1. A method for treating flue gas desulfurization wastewater according to Item 1.
濃度変化の値が基準値以上であるときは、前記硝化脱窒
工程後に前記活性炭処理工程を行い、 溶存酸素濃度変化の値が基準値以下であるときは、前記
活性炭処理工程後に前記硝化脱窒工程を行うことを特徴
とする請求項1又は2に記載の排煙脱硫排水の処理方
法。3. When the value of change in dissolved oxygen concentration measured by the biosensor is equal to or higher than a reference value, the activated carbon treatment step is performed after the nitrification / denitrification step, and the value of change in dissolved oxygen concentration is equal to or lower than a reference value. When it is, the method for treating flue gas desulfurization wastewater according to claim 1 or 2, wherein the nitrification denitrification step is performed after the activated carbon treatment step.
により変化する溶存酸素濃度を測定することにより、排
煙脱硫排水の毒性物質を検知するバイオセンサと、 該毒性物質あるいは該排水中に含まれる有機物を除去す
る活性炭処理装置と、該排水中のアンモニア性窒素化合
物を分解する硝化脱窒装置とを備えてなる請求項1〜3
のいずれかに記載の方法により該排水を処理するための
排煙脱硫排水の処理装置。4. A biosensor for detecting a toxic substance in flue gas desulfurization effluent by measuring a dissolved oxygen concentration which changes due to the presence of a toxic substance inhibiting microbial metabolism, and a toxic substance or a toxic substance contained in the effluent. 4. An activated carbon treatment device for removing organic matter to be removed, and a nitrification denitrification device for decomposing ammoniacal nitrogen compounds in the waste water.
An apparatus for treating flue gas desulfurization wastewater for treating the wastewater by the method according to any one of 1.
との間に設けられた1以上のバルブと、該バルブの開閉
を制御する手段とをさらに備えてなる請求項4に記載の
排煙脱硫排水の処理装置。5. The flue gas according to claim 4, further comprising one or more valves provided between the activated carbon treatment device and the nitrification / denitrification device, and means for controlling opening / closing of the valve. Desulfurization wastewater treatment equipment.
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Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN101856587A (en) * | 2010-06-02 | 2010-10-13 | 山东大学 | Fluidized activated carbon combined desulfurization and denitrification process |
JP2014083483A (en) * | 2012-10-22 | 2014-05-12 | Japan Organo Co Ltd | Persulfate processing apparatus, persulfate processing method, redox potential measuring device, and redox potential measuring method |
CN105084589A (en) * | 2015-08-06 | 2015-11-25 | 中冶华天工程技术有限公司 | Treatment method and system for wet magnesium desulphurization wastewater |
-
2001
- 2001-11-02 JP JP2001337267A patent/JP2003136092A/en not_active Withdrawn
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN101856587A (en) * | 2010-06-02 | 2010-10-13 | 山东大学 | Fluidized activated carbon combined desulfurization and denitrification process |
JP2014083483A (en) * | 2012-10-22 | 2014-05-12 | Japan Organo Co Ltd | Persulfate processing apparatus, persulfate processing method, redox potential measuring device, and redox potential measuring method |
CN105084589A (en) * | 2015-08-06 | 2015-11-25 | 中冶华天工程技术有限公司 | Treatment method and system for wet magnesium desulphurization wastewater |
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