JP2001070984A - Method for removing nitrogen from waste water - Google Patents
Method for removing nitrogen from waste waterInfo
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- JP2001070984A JP2001070984A JP25307499A JP25307499A JP2001070984A JP 2001070984 A JP2001070984 A JP 2001070984A JP 25307499 A JP25307499 A JP 25307499A JP 25307499 A JP25307499 A JP 25307499A JP 2001070984 A JP2001070984 A JP 2001070984A
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- nitrogen
- bacteria
- wastewater
- denitrification
- autotrophic
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- Purification Treatments By Anaerobic Or Anaerobic And Aerobic Bacteria Or Animals (AREA)
- Filtration Of Liquid (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、独立栄養細菌を用
いて、下水・排水中に含まれる窒素化合物を効率的に除
去する方法に関する。[0001] The present invention relates to a method for efficiently removing nitrogen compounds contained in sewage and wastewater using autotrophic bacteria.
【０００２】[0002]
【従来の技術】下水・排水からの窒素の除去方法として
は、生物学的脱窒素方法が広く知られている。窒素の形
態としてはアンモニア性窒素の形で含有されることが多
い。例えば、高濃度のアンモニア性窒素を含有する排水
は、製鉄所コークス工場、屎尿、肥料工場、半導体工
場、皮革工場などから発生する。製鉄所コークス工場か
ら発生するアンモニア性窒素含有排水は安水とも呼ば
れ、アンモニア性窒素を数百〜数千ｍｇ／ｌ程度も含有
している。一方、都市下水は、アンモニア性窒素を数十
ｍｇ／ｌ程度、養殖場排水は数ｍｇ／ｌ程度含有してい
る。2. Description of the Related Art As a method for removing nitrogen from sewage and wastewater, a biological denitrification method is widely known. Nitrogen is often contained in the form of ammoniacal nitrogen. For example, wastewater containing a high concentration of ammonia nitrogen is generated from ironworks coke factories, human waste, fertilizer factories, semiconductor factories, leather factories, and the like. Ammonia-containing nitrogen-containing wastewater generated from a steelworks coke plant is also referred to as low water, and contains about hundreds to thousands of mg / l of ammonia nitrogen. On the other hand, municipal sewage contains about tens of mg / l of ammonia nitrogen, and cultivation yard wastewater contains about several mg / l.
【０００３】このような下水・排水のアンモニア性窒素
の生物学的除去方法としては、好気性独立栄養細菌（ニ
トロゾモナス、ニトロバクター等の硝化細菌）による生
物学的酸化と通性嫌気性従属栄養細菌（シュードモナス
等）による生物学的還元の組み合わせから成る生物学的
硝化−脱窒素法が広く知見されている。[0003] As a method for biologically removing ammonia nitrogen from sewage and wastewater, biological oxidation by aerobic autotrophic bacteria (nitrifying bacteria such as nitrosomonas and nitrobacter) and facultative anaerobic heterotrophic bacteria are known. Biological nitrification-denitrification processes consisting of a combination of biological reductions (such as Pseudomonas) are widely known.
【０００４】まず、硝化工程は以下の２段の反応から成
っており、関与する硝化細菌の種類は異なっている。[0004] First, the nitrification process comprises the following two-stage reactions, and the types of nitrifying bacteria involved are different.
【０００５】 ２ＮＨ4 + ＋ ３Ｏ2 → ２ＮＯ2 -＋２Ｈ2Ｏ＋４Ｈ+ （１）[0005] 2NH 4 + + 3O 2 → 2NO 2 - + 2H 2 O + 4H + (1)
【０００６】 ２ＮＯ2 - ＋ Ｏ2 → ２ＮＯ3 - （２）2NO 2 − + O 2 → 2NO 3 − (2)
【０００７】（１）式に示す反応は、ニトロゾモナスを
代表種とする亜硝酸菌によってもたらされ、（２）式に
示す反応は、ニトロバクターを代表種とする硝酸菌によ
ってもたらされる。The reaction represented by the formula (1) is caused by nitrites represented by Nitrozomonas, and the reaction represented by the formula (2) is caused by nitrites represented by Nitrobacter.
【０００８】上記反応によって生成した亜硝酸性窒素な
らびに硝酸性窒素は、一般的に通性嫌気性従属栄養細菌
を用いて還元されて酸化窒素ガス（Ｎ2Ｏ）あるいは窒
素ガス（Ｎ2）となり、大気中に放散される。[0008] The nitrite nitrogen and nitrate nitrogen produced by the above reaction are generally reduced using a facultative anaerobic heterotrophic bacterium to become nitric oxide gas (N 2 O) or nitrogen gas (N 2 ). Dissipated into the atmosphere.
【０００９】 ２ＮＯ2 - ＋ ６Ｈ2 → Ｎ2 ＋２Ｈ2Ｏ＋２ＯＨ- （３）2NO 2 − + 6H 2 → N 2 + 2H 2 O + 2OH − (3)
【００１０】 ２ＮＯ3 - ＋１０Ｈ2 → Ｎ2 ＋４Ｈ2Ｏ＋２ＯＨ- （４）2NO 3 − + 10H 2 → N 2 + 4H 2 O + 2OH − (4)
【００１１】通性嫌気性従属栄養細菌は水素供与体が必
要であり、有機物質が通常利用される。都市下水では下
水中の有機物がそのまま用いられ、有機物を含まない排
水ではメタノールが添加される。A facultative anaerobic heterotrophic bacterium requires a hydrogen donor and usually uses organic substances. In municipal sewage, organic matter in sewage is used as it is, and in wastewater containing no organic matter, methanol is added.
【００１２】この生物学的硝化−脱窒素法は、アンモニ
ア性窒素濃度が１００ｍｇ／ｌ以下では問題が少なく、
また、最も安価で安定した処理方法である。This biological nitrification-denitrification method has few problems when the concentration of ammonia nitrogen is 100 mg / l or less.
Moreover, it is the cheapest and stable processing method.
【００１３】[0013]
【発明が解決しようとする課題】しかし、生物学的硝化
−脱窒素法は、アンモニア性窒素濃度が１００ｍｇ／ｌ
を超えると様々な課題が生じ、安定した処理が困難とな
る。すなわち、アンモニア性窒素濃度が１００ｍｇ／ｌ
を超えると、硝化工程において、アンモニア性窒素の酸
化が硝酸性窒素まで進行しないこと、すなわち、ニトロ
バクターが阻害を受け、処理水中の亜硝酸性窒素が蓄積
しやすいことが知見されている。この原因として、遊離
のアンモニウムイオンのニトロバクターへの阻害が知ら
れている。特に、ｐＨが高いと遊離のアンモニウムイオ
ンが発生する。However, the biological nitrification-denitrification method has an ammonia nitrogen concentration of 100 mg / l.
When the number exceeds, various problems occur, and stable processing becomes difficult. That is, the ammonia nitrogen concentration is 100 mg / l.
It has been found that, when the temperature exceeds the limit, in the nitrification step, the oxidation of ammoniacal nitrogen does not proceed to nitrate nitrogen, that is, the nitrobacter is inhibited, and the nitrite nitrogen in the treated water tends to accumulate. As a cause of this, inhibition of free ammonium ions on nitrobacter is known. In particular, when the pH is high, free ammonium ions are generated.
【００１４】亜硝酸性窒素は従属栄養細菌に対して毒性
が強く、処理水質が悪化しやすいことは広く知られてい
る（例えば、遠矢泰典、「下水道協会誌」、ＶＯＬ７、
ＮＯ７４、１９７０）。脱窒素に用いられている細菌
は、通常、従属栄養細菌であるから、蓄積した亜硝酸性
窒素によって脱窒素反応の進行に阻害が生ずる。脱窒素
反応の進行が停止すると、亜硝酸性窒素が処理水に流出
し、窒素規制をクリアできないばかりか、亜硝酸性窒素
起因のＣＯＤ（化学的酸素要求量）も増大してしまう。It is widely known that nitrite nitrogen is highly toxic to heterotrophic bacteria and easily deteriorates the quality of treated water (for example, Yasunori Toya, "Sewerage Association Journal", Vol.
NO 74, 1970). Since the bacteria used for denitrification are usually heterotrophic bacteria, the accumulated nitrite nitrogen inhibits the progress of the denitrification reaction. When the progress of the denitrification reaction is stopped, nitrite nitrogen flows out into the treated water, and not only nitrogen regulation cannot be cleared, but also COD (chemical oxygen demand) due to nitrite nitrogen increases.
【００１５】このようなことから、アンモニア性窒素濃
度が１００ｍｇ／ｌを超えるような排水の場合、従来の
生物学的硝化−脱窒素法の適用は、かなり困難である。[0015] For these reasons, in the case of wastewater having an ammonia nitrogen concentration exceeding 100 mg / l, it is quite difficult to apply the conventional biological nitrification-denitrification method.
【００１６】一方、脱窒性能を有する細菌は、従属栄養
細菌に限らない。水素細菌や硫黄酸化細菌などの独立栄
養細菌も、酸素の無い状態で脱窒素機能を有することは
広く知られている。これらの独立栄養細菌は、それぞれ
水素や還元性硫黄化合物を酸化した時に発生するエネル
ギーと空気中の炭酸ガスから菌体を合成し増殖する。こ
れらの細菌は、増殖速度が小さいことやフロック形成能
力が弱いこと等の理由から、脱窒素作用が知られている
ものの脱窒素に用いられた事例はほとんどない。On the other hand, bacteria having denitrification performance are not limited to heterotrophic bacteria. It is widely known that autotrophic bacteria such as hydrogen bacteria and sulfur oxidizing bacteria also have a denitrification function in the absence of oxygen. These autotrophic bacteria synthesize and grow cells from the energy generated when hydrogen and reducing sulfur compounds are oxidized and carbon dioxide in the air, respectively. Although these bacteria are known to have a denitrifying effect because of their low growth rate and weak floc-forming ability, they have hardly been used for denitrification.
【００１７】しかし、発明者らは、これらの独立栄養細
菌が亜硝酸性窒素に対し、従属栄養細菌と比較して極め
て強い耐性を有していることを知見した。すなわち、亜
硝酸性窒素濃度が２０００ｍｇ／ｌに上昇しても、脱窒
素速度の低下は見られなかった。したがって、アンモニ
ア性窒素を高濃度に含む排水処理の場合、脱窒素用の細
菌としては独立栄養細菌を用いた方が処理の安定化をも
たらす（特願平１１−１１７４１０号）。さらに、発明
者らは、独立栄養細菌の中でも、硫黄酸化細菌は、自己
造粒作用を有している場合もあるため、脱窒素槽での高
濃度化が容易で、処理の高効率化が可能であることを知
見している（特願平１０−１２２７１９号）。However, the inventors have found that these autotrophic bacteria have extremely strong resistance to nitrite nitrogen as compared to heterotrophic bacteria. That is, even if the nitrite nitrogen concentration increased to 2000 mg / l, no decrease in the denitrification rate was observed. Therefore, in the case of wastewater treatment containing a high concentration of ammonia nitrogen, the use of autotrophic bacteria as the bacteria for denitrification leads to more stable treatment (Japanese Patent Application No. 11-117410). Furthermore, among the autotrophic bacteria, the sulfur oxidizing bacteria may have a self-granulating effect, so that the concentration can be easily increased in the denitrification tank, and the treatment efficiency can be increased. They have found that this is possible (Japanese Patent Application No. 10-122719).
【００１８】このように、従属栄養細菌ではなく、亜硝
酸性窒素に耐性のある独立栄養細菌を用いることによ
り、従来は困難であった高濃度のアンモニア性窒素を含
有する排水の安定処理が可能となる。As described above, by using an autotrophic bacterium that is resistant to nitrite nitrogen instead of a heterotrophic bacterium, it is possible to stably treat wastewater containing a high concentration of ammonia nitrogen, which was difficult in the past. Becomes
【００１９】しかし、排水中の窒素濃度が高い場合、脱
窒素工程において発生する窒素ガス量が増大する。この
窒素ガスが独立栄養細菌に付着して脱窒素槽に浮き上が
り、脱窒素槽から流出しやすくなる傾向がある。したが
って、より安定した処理性能を得るためには、独立栄養
細菌の流出防止対策が必要となる。本発明は、上記課題
を解決するものである。However, when the nitrogen concentration in the wastewater is high, the amount of nitrogen gas generated in the denitrification step increases. This nitrogen gas adheres to the autotrophic bacteria, floats in the denitrification tank, and tends to flow out of the denitrification tank. Therefore, in order to obtain more stable processing performance, it is necessary to take measures to prevent the outflow of autotrophic bacteria. The present invention solves the above problems.
【００２０】[0020]
【課題を解決するための手段】本発明の要旨は、次の
（１）〜（６）である。The gist of the present invention is the following (1) to (6).
【００２１】（１）独立栄養細菌を用いて排水中の亜硝
酸性窒素および硝酸性窒素を窒素ガスに還元して排水か
ら除去する脱窒素方法において、独立栄養細菌の脱窒素
槽からの浮上流出を膜分離装置またはろ過装置を用いて
防止することにより、脱窒素槽内部で独立栄養細菌を高
濃度化させることを特徴とする排水からの窒素の除去方
法。(1) In a denitrification method for reducing nitrite nitrogen and nitrate nitrogen in wastewater by using autotrophic bacteria to remove nitrogen gas from the wastewater, the floating and outflow of autotrophic bacteria from the denitrification tank is carried out. By using a membrane separation device or a filtration device to increase the concentration of autotrophic bacteria inside the denitrification tank.
【００２２】（２）独立栄養細菌を用いて排水中の亜硝
酸性窒素および硝酸性窒素を窒素ガスに還元して排水か
ら除去する脱窒素方法において、独立栄養細菌の脱窒素
槽からの浮上流出を脱窒素槽内上部に設けたろ過部を用
いて防止することにより、脱窒素槽内部で独立栄養細菌
を高濃度化させることを特徴とする排水からの窒素の除
去方法。(2) In a denitrification method of reducing nitrite nitrogen and nitrate nitrogen in wastewater by using autotrophic bacteria to remove nitrogen gas from wastewater, the autotrophic bacteria float out of a denitrification tank. A high concentration of autotrophic bacteria in the denitrification tank by preventing the use of a filtration unit provided in the upper part of the denitrification tank.
【００２３】（３）独立栄養細菌として、造粒させた硫
黄酸化細菌または自己造粒作用を有する硫黄酸化細菌を
用いることを特徴とする前記（１）または（２）の排水
からの窒素の除去方法。(3) Removal of nitrogen from wastewater according to (1) or (2), wherein a granulated sulfur-oxidizing bacterium or a sulfur-oxidizing bacterium having a self-granulating action is used as the autotrophic bacterium. Method.
【００２４】（４）孔径が５００ミクロン以下の膜を用
いた膜分離装置を用いることを特徴とする前記（１）ま
たは（３）の排水からの窒素の除去方法。(4) The method for removing nitrogen from wastewater according to the above (1) or (3), wherein a membrane separation apparatus using a membrane having a pore diameter of 500 microns or less is used.
【００２５】（５）ろ材径が３ｍｍ以下のろ材を充填し
たろ過装置またはろ過部を用いることを特徴とする前記
（１）、（２）または（３）の排水からの窒素の除去方
法。(5) The method for removing nitrogen from wastewater according to the above (1), (2) or (3), wherein a filtration device or a filtration section filled with a filter medium having a filter medium diameter of 3 mm or less is used.
【００２６】（６）脱窒素槽下部および／またはろ過部
の下部に水中攪拌機を有することを特徴とする前記
（２）、（３）または（５）の排水からの窒素の除去方
法。(6) The method for removing nitrogen from wastewater according to the above (2), (3) or (5), wherein an underwater stirrer is provided below the denitrification tank and / or below the filtration unit.
【００２７】[0027]
【発明の実施の形態】脱窒素工程において、亜硝酸性窒
素に耐性のある独立栄養細菌を用いて亜硝酸性窒素を還
元して窒素ガスにする方法を用いると、硝化工程におい
て、亜硝酸性窒素を完全に硝酸性窒素まで酸化する必要
が無くなり、脱窒素槽の処理時間の短縮や維持管理が容
易となる。しかし、排水中の窒素濃度が１００ｍｇ／ｌ
を超えると、脱窒素反応により生成する窒素ガスにより
独立栄養細菌の浮上現象が生じる場合がある。独立栄養
細菌の中でも、自己造粒した硫黄酸化細菌を用いると、
粒径が１〜３ｍｍもあるため浮上はかなり抑制される。
しかし、完全な制御は困難である。BEST MODE FOR CARRYING OUT THE INVENTION In the denitrification step, a method of reducing nitrite nitrogen to nitrogen gas using an autotrophic bacterium resistant to nitrite nitrogen is used. There is no need to completely oxidize nitrogen to nitrate nitrogen, which shortens the processing time of the denitrification tank and facilitates maintenance. However, the nitrogen concentration in the wastewater is 100 mg / l
If the temperature exceeds, the floating phenomenon of autotrophic bacteria may occur due to nitrogen gas generated by the denitrification reaction. Among the autotrophic bacteria, using self-granulated sulfur oxidizing bacteria,
Since the particle diameter is as large as 1 to 3 mm, the floating is considerably suppressed.
However, complete control is difficult.
【００２８】ところで、下水や屎尿の活性汚泥処理にお
いて、膜分離装置の適用事例が数多く報告されるように
なった。これは、膜分離装置を用いて、活性汚泥を反応
槽内部に高濃度に維持して高効率処理をはかるものであ
る。膜としては、限外ろ過膜（ＵＦ：Ultra filtratio
n）や精密ろ過膜（ＭＦ：Micro filtration）が用いら
れている。膜を利用することで、反応槽内部の活性汚泥
濃度（ＭＬＳＳ）を６０００〜１００００ｍｇ／ｌに維
持できる。そして、浮遊性の粒径が小さな活性汚泥（数
１０ミクロン程度のフロック）を対象としているため、
孔径の小さな膜が使われることが多い。このため透過水
量が小さく、必要圧力も過大となる（例えば、和田洋六
著、「水のリサイクル」、地人書館、１７９〜１８０
頁）。By the way, in the activated sludge treatment of sewage and human waste, many examples of application of the membrane separation device have been reported. In this method, activated sludge is maintained at a high concentration in a reaction tank by using a membrane separation device, and high efficiency treatment is performed. As the membrane, an ultrafiltration membrane (UF: Ultra filtratio)
n) and a microfiltration membrane (MF: Micro filtration). By using the membrane, the activated sludge concentration (MLSS) inside the reaction tank can be maintained at 6000 to 10000 mg / l. And because it is intended for activated sludge (flock of several tens of microns) with a small floating particle size,
Often a membrane with a small pore size is used. For this reason, the amount of permeated water is small, and the required pressure is too large (for example, Yoro Wada, “Recycling of Water”, Jinjinkan, 179-180)
page).
【００２９】本発明においては、図１に示すようにＭＦ
膜（孔径：０．１〜１ミクロン）等を用いた膜分離装置
４により、独立栄養細菌の脱窒素槽２からの流出を防止
する。特に、１〜３ｍｍ程度の粒径を有する自己造粒し
た硫黄酸化細菌を用いた場合には、活性汚泥処理の際に
用いるように孔径の小さな膜を用いる必要は全くなく、
孔径が１０ミクロンから５００ミクロンと従来の膜と比
較して極めて大きなろ過膜でも十分対応できる。このた
め、透過水量も２０〜５０ｍ3／ｍ2と大きくとれる。な
お、５００ミクロン以上の孔径となると、自己造粒した
硫黄酸化細菌が柔らかいため、孔径中に入り込みやすく
なる。さらに、自己造粒した硫黄酸化細菌ばかりでな
く、凝集剤等を添加して強制的に造粒させた硫黄酸化細
菌を用いることもできる。In the present invention, as shown in FIG.
The outflow of autotrophic bacteria from the denitrification tank 2 is prevented by a membrane separation device 4 using a membrane (pore size: 0.1 to 1 micron) or the like. In particular, when a self-granulated sulfur oxidizing bacterium having a particle size of about 1 to 3 mm is used, there is no need to use a membrane having a small pore size as used in the activated sludge treatment.
An extremely large filtration membrane having a pore size of 10 μm to 500 μm as compared with a conventional membrane can sufficiently cope with the problem. Therefore, the amount of permeated water can be as large as 20 to 50 m 3 / m 2 . When the pore size is 500 microns or more, the self-granulated sulfur-oxidizing bacteria are soft and easily enter the pore size. Further, not only self-granulated sulfur-oxidizing bacteria but also sulfur-oxidizing bacteria which are forcibly granulated by adding a coagulant or the like can be used.
【００３０】また、図２に示すように、砂、砂利、セラ
ミックスまたは浮遊性濾剤等をろ剤として充填したろ過
装置８を用いても、独立栄養細菌の脱窒素槽２からの流
出を防止できる。膜分離装置の場合と同様に、１〜３ｍ
ｍ程度の粒径を有する自己造粒した硫黄酸化細菌を用い
た場合には、従来の砂ろ過装置に用いられているような
ろ剤径：０．４５〜０．７ｍｍという粒径の小さな砂を
用いる必要は全くなく、１〜３ｍｍの砂利で対応でき
る。ろ過速度も２００〜５００ｍ／日程度まで可能であ
った。一般に、ろ過は膜分離と除去機構が全く異なって
おり、除去対象物質のろ剤表面への輸送（阻止作用と重
力沈降作用）および除去対象物質のろ剤表面での付着が
重要な因子である。したがって、最適なろ材径やろ過速
度は実験的に求めざるを得ない。なお、１〜３ｍｍの砂
利をろ材として用いた実験で、ろ過速度を５００ｍ／日
以上にあげると、処理水中に硫黄酸化細菌の流出が観察
された。Further, as shown in FIG. 2, even if a filtration device 8 filled with sand, gravel, ceramics, or a buoyant filter medium is used as a filter medium, the outflow of autotrophic bacteria from the denitrification tank 2 can be prevented. it can. 1 to 3 m, as in the case of the membrane separation device
When a self-granulated sulfur oxidizing bacterium having a particle size of about m is used, a small sand having a particle size of 0.45 to 0.7 mm as used in a conventional sand filter is used. There is no need to use it at all, and gravel of 1 to 3 mm can be used. The filtration speed was also possible up to about 200 to 500 m / day. Generally, filtration is completely different from membrane separation and removal mechanism, and the important factors are transport of the substance to be removed to the surface of the filter medium (inhibition and gravitational sedimentation) and adhesion of the substance to be removed on the surface of the filter medium. . Therefore, the optimum filter media diameter and filtration speed must be determined experimentally. In an experiment using a gravel of 1 to 3 mm as a filter medium, when the filtration speed was increased to 500 m / day or more, outflow of sulfur-oxidizing bacteria was observed in the treated water.
【００３１】ろ剤の種類としては、砂、砂利ばかりでな
く、成形したセラミックス、アンスラサイトまたは浮遊
性のろ剤等を用いることもできる。さらに、図３に示す
ように、ろ過部９を脱窒素槽２内の上部に設置すること
により脱窒素槽２と一体化することもできる。この場
合、窒素ガスの放散を促すためのガス抜き配管１２を設
けることが望ましい。さらに、ろ過部と組み合わせる場
合、浮上した硫黄酸化細菌がろ材に付着するのを防止す
るため、脱窒素槽下部および／またはろ過部の下部に水
中攪拌機１０を設けることが望ましい。As the type of the filtering agent, not only sand and gravel, but also formed ceramics, anthracite or a floating filtering agent can be used. Further, as shown in FIG. 3, the filtration unit 9 can be integrated with the denitrification tank 2 by installing the filtration unit 9 in the upper part of the denitrification tank 2. In this case, it is desirable to provide a gas vent pipe 12 for promoting nitrogen gas emission. Furthermore, when combined with the filtration unit, it is desirable to provide the underwater stirrer 10 below the denitrification tank and / or below the filtration unit in order to prevent the sulfur-oxidizing bacteria that have floated from attaching to the filter medium.
【００３２】[0032]
【実施例】以下、本発明の実施例を説明する。Embodiments of the present invention will be described below.
【００３３】（実施例１）製鉄所コークス工場安水処理
への適用(Embodiment 1) Application to steelworks coke factory water treatment
【００３４】本発明の方法を、製鉄所コークス工場から
発生する安水の活性汚泥処理水の脱窒素に適用した。安
水はフエノールが主体の排水であるが、アンモニア性窒
素を１０００〜５０００ｍｇ／ｌ程度含有している。従
来は海水で３〜５倍程度に希釈し、活性汚泥によりフェ
ノールを中心に分解除去していた。このような安水活性
汚泥処理水は、活性汚泥によってフェノール等の有機物
は除去されているものの、アンモニア性窒素を３００〜
１０００ｍｇ／ｌ含有していることが多い。The method of the present invention was applied to the denitrification of the activated sludge treated water of the aqua water generated from the coke plant of the steelworks. The cheap water is a wastewater mainly composed of phenol, and contains about 1000 to 5000 mg / l of ammonia nitrogen. Conventionally, it is diluted about 3 to 5 times with seawater, and phenol is mainly decomposed and removed by activated sludge. In such a treated water with activated sludge, although organic substances such as phenol are removed by activated sludge, ammonia-based nitrogen is reduced by 300 to
It often contains 1000 mg / l.
【００３５】処理フローを図４に示す。FIG. 4 shows the processing flow.
【００３６】硝化槽１４でアンモニア性窒素を亜硝酸性
窒素まで酸化するために、以下の運転条件で硝化槽１４
を運転した。まず、硝化槽１４にセラミック担体をリア
クター容積あたり７０％投入し、硝化細菌を付着させた
（固定床型バイオリアクター）。次に、硫酸および水酸
化ナトリウムによってｐＨを７〜８に制御するととも
に、空気および／または酸素により、ＤＯを２ｍｇ／ｌ
以上、またＯＲＰを＋１５０ｍＶ（銀／塩化銀基準）以
上に維持するように運転した。アンモニア性窒素容積負
荷が５ｋｇ−Ｎ／ｍ3・日の範囲で、アンモニア性窒素
（８５０ｍｇ／ｌ）は８０％が亜硝酸性窒素に、２０％
が硝酸性窒素になった。In order to oxidize ammonia nitrogen to nitrite nitrogen in the nitrification tank 14, the nitrification tank 14 is operated under the following operating conditions.
Drove. First, a ceramic carrier was charged into the nitrification tank 14 at a rate of 70% per reactor volume to allow nitrifying bacteria to adhere (fixed-bed type bioreactor). Next, the pH is controlled to 7 to 8 with sulfuric acid and sodium hydroxide, and DO is adjusted to 2 mg / l with air and / or oxygen.
The operation was also performed so as to maintain the ORP at +150 mV (silver / silver chloride standard) or higher. When the ammonia nitrogen volume load is in the range of 5 kg-N / m 3 · day, 80% of the ammonia nitrogen (850 mg / l) is converted to nitrite nitrogen and 20%
Became nitrate nitrogen.
【００３７】脱窒素槽２に自己造粒させた硫黄酸化細菌
を投入し、硫黄源としてチオ硫酸を硫黄として窒素の３
倍量添加した。硫酸および水酸化ナトリウムによってｐ
Ｈを７〜８に制御するとともに、硝酸性窒素と亜硝酸性
窒素の容積負荷が１０ｋｇ−Ｎ／ｍ3・日の条件で運転
したところ、処理水中の窒素濃度は１０ｍｇ／ｌ以下と
なった。後段に、サドル型のセラミックス（サイズ：１
インチ）を充填したろ過装置８を設置した。ろ過速度を
２００ｍ／日で運転したが、処理水５に自己造粒した硫
黄酸化細菌の流出は観察されなかった。Self-granulated sulfur-oxidizing bacteria are put into a denitrification tank 2 and thiosulfuric acid is used as a sulfur source and nitrogen is used as sulfur.
Double amount was added. P with sulfuric acid and sodium hydroxide
When H was controlled to 7 to 8 and the volume load of nitrate nitrogen and nitrite nitrogen was operated under the condition of 10 kg-N / m 3 · day, the nitrogen concentration in the treated water became 10 mg / l or less. . The saddle-shaped ceramics (size: 1)
) Was installed. The system was operated at a filtration speed of 200 m / day, but no outflow of sulfur-oxidizing bacteria self-granulated in the treated water 5 was observed.
【００３８】処理水中に残留するチオ硫酸は、好気性硫
黄酸化細菌を用いた生物酸化槽１６において硫酸イオン
まで酸化した。生物酸化槽１６では、曝気によって溶存
酸素を２ｍｇ／ｌ以上に維持した。生物酸化槽１６の滞
留時間が１時間でチオ硫酸は硫酸イオンまで酸化され、
ＣＯＤも２０ｍｇ／ｌ以下となった。Thiosulfuric acid remaining in the treated water was oxidized to sulfate ions in a biological oxidation tank 16 using aerobic sulfur-oxidizing bacteria. In the biological oxidation tank 16, the dissolved oxygen was maintained at 2 mg / l or more by aeration. Thiosulfuric acid is oxidized to sulfate ions in the residence time of the biological oxidation tank 16 for 1 hour,
COD was also 20 mg / l or less.
【００３９】（実施例２）屎尿処理活性汚泥処理水への
適用(Example 2) Application to human sludge treated activated sludge treated water
【００４０】従来の標準的な脱窒素法では、収集屎尿を
１０〜２０倍程度に希釈した後、活性汚泥で処理し有機
物除去（ＢＯＤ）を行っていた。窒素除去も併せて行う
場合には、硝化液を脱窒素槽に循環し、排水中の有機物
により脱窒素を行い、脱窒素−硝化のフローとなる循環
式硝化−脱窒素法が採用されている場合が多い。しか
し、窒素除去を行う場合、亜硝酸性窒素蓄積が生じやす
く、窒素除去効率が低下しやすい。このため、希釈倍率
が大きくなり、施設の巨大化を招いてしまう。なお、収
集屎尿の水質は、ＢＯＤが１００００〜２００００ｍｇ
／ｌ、ＣＯＤが５０００〜１００００ｍｇ／ｌ、ＴＮが
５０００〜１００００ｍｇ／ｌ（大半が有機性窒素とア
ンモニア性窒素）程度である。In the conventional standard denitrification method, collected manure is diluted about 10 to 20 times and then treated with activated sludge to remove organic substances (BOD). In the case where nitrogen removal is also performed, a recirculating nitrification-denitrification method in which a nitrification liquid is circulated to a denitrification tank, and denitrification is performed using organic matter in wastewater, and a denitrification-nitrification flow is adopted. Often. However, when performing nitrogen removal, nitrite nitrogen accumulation tends to occur, and the nitrogen removal efficiency tends to decrease. For this reason, the dilution ratio becomes large, and the facility becomes large. In addition, the water quality of collected manure is BOD of 10,000 to 20,000 mg.
/ L, COD of 5000 to 10000 mg / l, and TN of 5000 to 10000 mg / l (mostly organic nitrogen and ammonia nitrogen).
【００４１】図５に示す処理フローで、本発明を屎尿処
理に適用した。屎尿を淡水で３倍に希釈後、まず、活性
汚泥により有機物を除去した。In the processing flow shown in FIG. 5, the present invention was applied to human waste processing. After the human waste was diluted three times with fresh water, first, organic matter was removed with activated sludge.
【００４２】その後、硝化槽１４でアンモニア性窒素を
亜硝酸性窒素まで酸化するために、以下の運転条件で硝
化槽１４を運転した。まず、硝化槽１４には浮遊性の円
筒型プラスチックス担体（内径３ｍｍ、長さ４ｍｍ）を
硝化槽容積あたり２５％投入し、硝化菌を付着させた
（流動床型バイオリアクター）。次に、硫酸および水酸
化ナトリウムによってｐＨを７〜８に制御するととも
に、空気および／または酸素により、ＤＯを２ｍｇ／ｌ
以上、ＯＲＰを＋１５０ｍＶ（銀／塩化銀基準）以上に
維持するように運転した。硝化槽１４のアンモニア性窒
素容積負荷が５ｋｇ−Ｎ／ｍ3・日の条件で、有機性窒
素とアンモニア性窒素の合計（２５００ｍｇ／ｌ）は９
０％が亜硝酸性窒素に、１０％が硝酸性窒素になった。Thereafter, in order to oxidize ammonia nitrogen to nitrite nitrogen in the nitrification tank 14, the nitrification tank 14 was operated under the following operating conditions. First, a floating cylindrical plastics carrier (inner diameter 3 mm, length 4 mm) was charged into the nitrification tank 14 at a rate of 25% per volume of the nitrification tank, and nitrifying bacteria were allowed to adhere (fluidized bed bioreactor). Next, the pH is controlled to 7 to 8 with sulfuric acid and sodium hydroxide, and DO is adjusted to 2 mg / l with air and / or oxygen.
As described above, the operation was performed so as to maintain the ORP at +150 mV (based on silver / silver chloride). Under the condition that the ammonia nitrogen volume load of the nitrification tank 14 is 5 kg-N / m 3 · day, the total of organic nitrogen and ammonia nitrogen (2500 mg / l) is 9
0% became nitrite nitrogen and 10% became nitrate nitrogen.
【００４３】さらに、脱窒素槽２に自己造粒させた硫黄
酸化細菌を投入し、硫黄源としてチオ硫酸を硫黄として
窒素の３倍量添加した。脱窒素槽２の上部には、浮遊性
の円筒型プラスチックス担体（内径：３ｍｍ；長さ４ｍ
ｍ）を脱窒素槽２の容積あたり２５％投入した。また、
脱窒素槽２の下部中央に水中攪拌機を設置し、常時攪拌
することにより、プラスチックス担体に浮上した硫黄酸
化細菌が固着することを防止した。硫酸および水酸化ナ
トリウムによってｐＨを７〜８に制御するとともに、硝
酸性窒素と亜硝酸性窒素の容積負荷が１５ｋｇ−Ｎ／ｍ
3・日の条件で運転したが、処理水中の窒素濃度は５ｍ
ｇ／ｌ以下となった。さらに、処理水中に残留するチオ
硫酸は、生物酸化槽１６によって硫酸イオンまで酸化し
た。生物酸化槽１６では、曝気によって溶存酸素を２ｍ
ｇ／ｌ以上に維持した。滞留時間１時間でチオ硫酸は硫
酸イオンまで酸化され、ＣＯＤも２０ｍｇ／ｌ以下とな
った。Further, self-granulated sulfur-oxidizing bacteria were put into the denitrification tank 2, and thiosulfuric acid was added as a sulfur source in an amount three times as much as nitrogen as sulfur. Above the denitrification tank 2, a floating cylindrical plastic carrier (inner diameter: 3 mm; length: 4 m)
m) was charged at 25% per volume of the denitrification tank 2. Also,
A submerged stirrer was installed in the lower center of the denitrification tank 2 to constantly stir to prevent the sulfur-oxidizing bacteria floating on the plastics carrier from sticking. The pH is controlled to 7 to 8 with sulfuric acid and sodium hydroxide, and the volume load of nitrate nitrogen and nitrite nitrogen is 15 kg-N / m
It was operated under the condition of 3 days, but the nitrogen concentration in the treated water was 5m
g / l or less. Further, the thiosulfuric acid remaining in the treated water was oxidized by the biological oxidation tank 16 to sulfate ions. In the biological oxidation tank 16, the dissolved oxygen is reduced by 2 m by aeration.
g / l. At a residence time of 1 hour, thiosulfuric acid was oxidized to sulfate ions, and COD was reduced to 20 mg / l or less.
【００４４】[0044]
【発明の効果】本発明により、独立栄養細菌を用いてア
ンモニア性窒素を高濃度に含有する排水を処理する際に
発生する、細菌の浮上流出による処理効率低下を防止で
き、安定した窒素除去が可能となる。Industrial Applicability According to the present invention, it is possible to prevent a decrease in treatment efficiency due to floating and outflow of bacteria, which is generated when treating wastewater containing ammonia nitrogen at a high concentration by using an autotrophic bacterium. It becomes possible.
【図１】膜分離装置を用いて本発明の方法を実施するた
めの装置を示す図である。FIG. 1 is a diagram showing an apparatus for performing the method of the present invention using a membrane separation apparatus.
【図２】ろ過装置を用いて本発明の方法を実施するため
の装置を示す図である。FIG. 2 is a diagram showing an apparatus for performing the method of the present invention using a filtration apparatus.
【図３】脱窒素槽内のろ過部を用いて本発明の方法を実
施するための装置を示す図である。FIG. 3 is a diagram showing an apparatus for performing the method of the present invention using a filtration unit in a denitrification tank.
【図４】本発明方法において、ろ過装置を用いる処理フ
ローを示す図である。FIG. 4 is a diagram showing a processing flow using a filtration device in the method of the present invention.
【図５】本発明方法において、ろ過部を有する脱窒素槽
を用いる処理フローを示す図である。FIG. 5 is a diagram showing a processing flow using a denitrification tank having a filtration unit in the method of the present invention.
１ 流入水 ２ 脱窒素槽 ３ 循環ポンプ ４ 膜分離装置 ５ 処理水 ６ 循環水 ７ 移送ポンプ ８ ろ過装置 ９ ろ過部 １０ 水中攪拌機 １１ 液循環用配管 １２ ガス抜き配管 １３ 安水活性汚泥処理水 １４ 硝化槽 １５ チオ硫酸添加槽 １６ 生物酸化槽 １７ 屎尿活性汚泥処理水 DESCRIPTION OF SYMBOLS 1 Inflow water 2 Denitrification tank 3 Circulation pump 4 Membrane separation device 5 Treated water 6 Circulation water 7 Transfer pump 8 Filtration device 9 Filtration part 10 Underwater agitator 11 Liquid circulation pipe 12 Gas release pipe 13 Water-activated activated sludge treatment water 14 Nitrification Tank 15 Thiosulfuric acid addition tank 16 Biological oxidation tank 17 Sewage activated sludge treated water
Claims (6)
窒素および硝酸性窒素を窒素ガスに還元して排水から除
去する脱窒素方法において、独立栄養細菌の脱窒素槽か
らの浮上流出を膜分離装置またはろ過装置を用いて防止
することにより、脱窒素槽内部で独立栄養細菌を高濃度
化させることを特徴とする排水からの窒素の除去方法。1. A denitrification method for reducing nitrite nitrogen and nitrate nitrogen in waste water by using autotrophic bacteria to remove the waste water from the waste water by reducing it to nitrogen gas. A method for removing nitrogen from wastewater, comprising increasing the concentration of autotrophic bacteria inside a denitrification tank by preventing the bacteria using a membrane separation device or a filtration device.
窒素および硝酸性窒素を窒素ガスに還元して排水から除
去する脱窒素方法において、独立栄養細菌の脱窒素槽か
らの浮上流出を脱窒素槽内上部に設けたろ過部を用いて
防止することにより、脱窒素槽内部で独立栄養細菌を高
濃度化させることを特徴とする排水からの窒素の除去方
法。2. A denitrification method in which nitrite nitrogen and nitrate nitrogen in wastewater are reduced to nitrogen gas and removed from wastewater using an autotrophic bacterium. A method for removing nitrogen from wastewater, comprising increasing the concentration of autotrophic bacteria inside a denitrification tank by preventing the same using a filtration unit provided in an upper part of the denitrification tank.
化細菌または自己造粒作用を有する硫黄酸化細菌を用い
ることを特徴とする請求項１または２記載の排水からの
窒素の除去方法。3. The method for removing nitrogen from wastewater according to claim 1, wherein a granulated sulfur-oxidizing bacterium or a sulfur-oxidizing bacterium having a self-granulating action is used as the autotrophic bacterium.
膜分離装置を用いることを特徴とする請求項１または３
記載の排水からの窒素の除去方法。4. The method according to claim 1, wherein a membrane separation device using a membrane having a pore diameter of 500 μm or less is used.
The method for removing nitrogen from wastewater as described in the above.
過装置またはろ過部を用いることを特徴とする請求項
１、２または３記載の排水からの窒素の除去方法。5. The method for removing nitrogen from wastewater according to claim 1, wherein a filtration device or a filtration section filled with a filter medium having a filter medium diameter of 3 mm or less is used.
部に水中攪拌機を有することを特徴とする請求項２、３
または５記載の排水からの窒素の除去方法。6. An underwater stirrer is provided below the denitrification tank and / or below the filtration unit.
Or the method for removing nitrogen from wastewater according to 5.
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|---|---|---|---|
| JP25307499A JP4031597B2 (en) | 1999-09-07 | 1999-09-07 | How to remove nitrogen from wastewater |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002316189A (en) * | 2001-04-18 | 2002-10-29 | Hitachi Plant Eng & Constr Co Ltd | Biological treatment apparatus and autotrophic sulfur denitrification method |
| KR100722655B1 (en) * | 2001-07-18 | 2007-05-28 | 현대중공업 주식회사 | Advanced wastewater treatment system with alkalinity-added sulfur media and submerged membrane module |
| KR101352247B1 (en) * | 2004-12-14 | 2014-01-15 | 쿠리타 고교 가부시키가이샤 | Apparatus for treating waste water |
| CN103723893A (en) * | 2014-01-10 | 2014-04-16 | 中国科学院生态环境研究中心 | Method for removing nitrate nitrogen from water |
| WO2014129759A1 (en) * | 2013-02-20 | 2014-08-28 | 주식회사 부강테크 | Wastewater treatment device using separation membrane with which recovery of granules of active microorganisms is possible and method for treating wastewater using same |
| CN112850895A (en) * | 2021-01-29 | 2021-05-28 | 安道麦安邦(江苏)有限公司 | Method and device for treating pymetrozine organic nitrogen wastewater |
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1999
- 1999-09-07 JP JP25307499A patent/JP4031597B2/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002316189A (en) * | 2001-04-18 | 2002-10-29 | Hitachi Plant Eng & Constr Co Ltd | Biological treatment apparatus and autotrophic sulfur denitrification method |
| KR100722655B1 (en) * | 2001-07-18 | 2007-05-28 | 현대중공업 주식회사 | Advanced wastewater treatment system with alkalinity-added sulfur media and submerged membrane module |
| KR101352247B1 (en) * | 2004-12-14 | 2014-01-15 | 쿠리타 고교 가부시키가이샤 | Apparatus for treating waste water |
| WO2014129759A1 (en) * | 2013-02-20 | 2014-08-28 | 주식회사 부강테크 | Wastewater treatment device using separation membrane with which recovery of granules of active microorganisms is possible and method for treating wastewater using same |
| CN103723893A (en) * | 2014-01-10 | 2014-04-16 | 中国科学院生态环境研究中心 | Method for removing nitrate nitrogen from water |
| CN112850895A (en) * | 2021-01-29 | 2021-05-28 | 安道麦安邦(江苏)有限公司 | Method and device for treating pymetrozine organic nitrogen wastewater |
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