JP6535125B1 - Water treatment method - Google Patents

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JP6535125B1
JP6535125B1 JP2018118619A JP2018118619A JP6535125B1 JP 6535125 B1 JP6535125 B1 JP 6535125B1 JP 2018118619 A JP2018118619 A JP 2018118619A JP 2018118619 A JP2018118619 A JP 2018118619A JP 6535125 B1 JP6535125 B1 JP 6535125B1
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denitrification
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JP2019217481A (en
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將貴 三宅
將貴 三宅
長谷部 吉昭
吉昭 長谷部
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Organo Corp
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract

【課題】アンモニア態窒素および有機態窒素を含む被処理水の生物学的処理において、被処理水中の窒素濃度が高濃度であっても高い処理速度で安定して処理することができる水処理方法および水処理装置を提供する。【解決手段】アンモニア態窒素および有機態窒素を含む被処理水を、生物学的に処理する水処理方法および水処理方法であって、微生物活性汚泥中に含まれる独立栄養性のアンモニア酸化菌と亜硝酸酸化菌とを含む硝化菌により、アンモニア態窒素を亜硝酸または硝酸態窒素にまで酸化する硝化装置10(硝化工程)を含み、硝化装置10において、被処理水に対して、モリブデン濃度が0.025mgMo/gN以上となるようにモリブデン化合物を存在させる、水処理装置1(水処理方法)である。【選択図】図1PROBLEM TO BE SOLVED: In the biological treatment of treated water containing ammonia nitrogen and organic nitrogen, a water treatment method capable of stably treating with high treatment speed even if nitrogen concentration in the treated water is high concentration And provide water treatment equipment. A water treatment method and a water treatment method for biologically treating treated water containing ammonia nitrogen and organic nitrogen, comprising autotrophic ammonia oxidizing bacteria contained in microbial activated sludge It includes a nitrification device 10 (nitrification process) that oxidizes ammonia nitrogen to nitrite or nitrate nitrogen by nitrifying bacteria containing nitrite oxidizing bacteria, and the nitrification device 10 has a molybdenum concentration relative to the water to be treated It is a water treatment apparatus 1 (water treatment method) in which a molybdenum compound is made to be 0.025 mg Mo / gN or more. [Selected figure] Figure 1

Description

本発明は、被処理水中に含まれるアンモニア態窒素を生物学的に窒素ガスにまで酸化、還元する水処理方法および水処理装置に関する。   The present invention relates to a water treatment method and a water treatment apparatus which biologically oxidize and reduce ammonia nitrogen contained in water to be treated to nitrogen gas.

排水中に含まれる窒素成分は、湖沼や閉鎖性海域等における富栄養化の原因物質の一つであるため、特に排水中に窒素成分が高濃度で含まれる場合は、排水処理工程で除去する必要がある。一般的には、微生物活性汚泥を用いた生物学的処理が適用されることが多く、例えば、アンモニア態窒素や有機態窒素を含んだ被処理水において、好気条件においてアンモニア態窒素を亜硝酸または硝酸態窒素にまで酸化する硝化工程、無酸素条件下、水素供与体存在下で亜硝酸、硝酸態窒素を窒素ガスにまで還元する脱窒工程、という2工程により硝化脱窒処理が行われる。また、被処理水中に多量の有機物を含む場合、被処理水を脱窒槽に供給するとともに、硝化槽で生成した亜硝酸、硝酸態窒素を含む混合液を脱窒槽へと循環し、被処理水中の有機物を水素供与体として利用して脱窒する循環型硝化脱窒法により処理が行われることもある。   The nitrogen component contained in the waste water is one of the causative agents of eutrophication in lakes and closed areas, etc. Therefore, it is removed by the waste water treatment process, especially when the waste water contains a high concentration of nitrogen component. There is a need. In general, biological treatment using microbial activated sludge is often applied, for example, ammonia nitrogen in an aerobic condition and nitrous acid in treated water containing ammonia nitrogen and organic nitrogen. Alternatively, the nitrification and denitrification treatment is performed in two steps, a nitrification step that oxidizes to nitrate nitrogen, a denitrification step that reduces nitrous acid and nitrate nitrogen to nitrogen gas in the presence of hydrogen donor under anoxic conditions and without hydrogen. . In addition, when the water to be treated contains a large amount of organic substances, the water to be treated is supplied to the denitrification tank, and the mixed solution containing nitrous acid and nitrate nitrogen generated in the nitrification tank is circulated to the denitrification tank to treat the water to be treated. There are also cases where the treatment is carried out by a circulating nitrification denitrification method in which denitrification is carried out by using the organic substance of the above as a hydrogen donor.

いずれの処理方法においても、微生物活性汚泥中の硝化菌および脱窒菌を利用するものであるが、脱窒菌は有機物を資化可能な従属栄養性細菌であるのに対し、硝化菌は無機炭素を炭素源とする独立栄養性細菌であるため、脱窒菌と比較して増殖速度が非常に遅い。微生物活性汚泥を用いた処理方法の場合、活性汚泥中に硝化菌と脱窒菌が混在しているため、増殖速度が低い独立栄養性細菌である硝化菌の汚泥中での存在割合は非常に小さいと言われている。窒素含有排水の処理に対して、硝化脱窒法を利用した場合、排水中の窒素の除去効率は、硝化工程における硝化菌の活性が律速となる。また、硝化菌は水温の影響を大きく受け、水温低下が大幅な活性低下を招く恐れがある。そのため、処理水質を悪化させないために、硝化工程における汚泥当りの硝化速度(アンモニア酸化比活性)を脱窒工程のそれよりも低くする必要がある。例えば、非特許文献1には、アンモニア酸化比活性は0.113mgN/(mgVSS・日)、亜硝酸酸化非活性は0.056mgN/(mgVSS・日)であったと報告されている。実処理においても、水温20℃の条件において、汚泥あたりの処理速度として0.05〜0.1kgN/(kgVSS・日)程度で運転するように硝化槽の容積負荷を設定することが多い。   Although any treatment method utilizes nitrifying bacteria and denitrifying bacteria in the microorganism activated sludge, denitrifying bacteria are heterotrophic bacteria that can assimilate organic matter, whereas nitrifying bacteria use inorganic carbon. Because they are autotrophic bacteria that are carbon sources, their growth rate is very slow compared to denitrifying bacteria. In the case of treatment method using microbial activated sludge, the presence ratio of nitrifying bacteria, which are autotrophic bacteria with low growth rate, in the sludge is very small because nitrifying bacteria and denitrifying bacteria are mixed in the activated sludge. It is said. When the nitrification denitrification method is used for the treatment of nitrogen-containing wastewater, the removal efficiency of nitrogen in the wastewater is limited by the activity of nitrifying bacteria in the nitrification step. In addition, nitrifying bacteria are greatly affected by the water temperature, and there is a possibility that the decrease in water temperature causes a significant decrease in activity. Therefore, in order not to deteriorate the treated water quality, it is necessary to make the nitrification rate per sludge (ammonia oxidation specific activity) in the nitrification step lower than that in the denitrification step. For example, Non-Patent Document 1 reports that the ammonia oxidation specific activity is 0.113 mg N / (mg VSS · day), and the nitrite non-oxidation activity is 0.056 mg N / (mg VSS · day). Also in actual treatment, the volume load of the nitrification tank is often set to operate at a treatment rate of about 0.05 to 0.1 kgN / (kgVSS · day) as the treatment rate per sludge under the condition of water temperature of 20 ° C.

一方で、被処理水中の窒素濃度が例えば100mgN/L以上のように、高濃度の窒素を含有する被処理水を硝化菌および脱窒菌を含む微生物活性汚泥により処理を行う場合においては、硝化工程における硝化活性が低下してしまうことがある。硝化活性が低下すると最終処理水質をも悪化させてしまうため、硝化工程の汚泥あたりの硝化速度を上記の0.05〜0.1kgN/(kgMLVSS・日)よりも低く設定しなければならず、その結果として処理速度を高く保つことが困難となる場合がある。   On the other hand, when the water to be treated containing high concentration of nitrogen is treated with the microorganism activated sludge containing nitrifying bacteria and denitrifying bacteria such as nitrogen concentration in the water to be treated being 100 mg N / L or more, the nitrification step In some cases, the nitrification activity in the If the nitrification activity decreases, the final treated water quality is also deteriorated, so the nitrification rate per sludge in the nitrification step must be set lower than the above-mentioned 0.05 to 0.1 kgN / (kgMLVSS · day), As a result, it may be difficult to keep the processing speed high.

特開2006−272287号公報JP, 2006-272287, A

荒木ら(1999)、FISH法を適用した生物膜内硝化細菌の菌数計測と空間分布の解析;水環境学会誌第22巻、第2号、pp.152−159Araki et al. (1999), Measurement of the number of bacteria and spatial distribution of nitrifying bacteria in biofilms applying FISH method; Journal of Water Environment Society Vol. 22, No. 2, pp. 152-159 Microbiology nitrate respiration - Genes, enzymes, and environmental distribution, Journal of Biotechnology, 155(2011), pp.104-117Microbiology nitrate relocation-Genes, enzymes, and environmental distribution, Journal of Biotechnology, 155 (2011), pp. 104-117 Molybdenum as a micronutrient for Nitrobacter, Journal of Bacteriology, 89(1965), pp.123-128Molybdenum as a micronutrient for Nitrobacter, Journal of Bacteriology, 89 (1965), pp. 123-128 Molecular analysis of ammonia oxidation and denitrification in natural environments , FEMS Microbiology Reviews, 24(2000), pp.673-690Molecular analysis of ammonia oxidation and denitrification in natural environments, FEMS Microbiology Reviews, 24 (2000), pp. 673-690

本発明の目的は、アンモニア態窒素および有機態窒素を含む被処理水の生物学的処理において、被処理水中の窒素濃度が高濃度であっても高い処理速度で安定して処理することができる水処理方法および水処理装置を提供することにある。   It is an object of the present invention to be able to stably treat at high treatment speed even if nitrogen concentration in water to be treated is high in biological treatment of water to be treated containing ammonia nitrogen and organic nitrogen A water treatment method and a water treatment apparatus are provided.

本発明は、アンモニア態窒素および有機態窒素を含む被処理水を、生物学的に処理する水処理方法であって、微生物活性汚泥中に含まれる独立栄養性のアンモニア酸化菌と亜硝酸酸化菌とを含む硝化菌により、前記アンモニア態窒素を亜硝酸または硝酸態窒素にまで酸化する硝化工程を含み、前記硝化工程において、前記被処理水に対して、モリブデン濃度が0.025mgMo/gN以上となるようにモリブデン化合物を存在させ、汚泥あたりの硝化速度が、0.11[kgN/(kgVSS・日)]以上である、水処理方法である。 The present invention is a water treatment method for biologically treating treated water containing ammonia nitrogen and organic nitrogen, which comprises autotrophic ammonia oxidizing bacteria and nitrite oxidizing bacteria contained in microorganism activated sludge. And oxidizing the ammoniacal nitrogen to nitrous acid or nitrate nitrogen by the nitrifying bacteria, and the molybdenum concentration in the water to be treated in the nitrification process is 0.025 mgMo / gN or more. in the presence of a molybdenum compound such that, nitrification speed of the sludge, Ru der 0.11 [kgN / (kgVSS · day)] or more, a water treatment process.

前記水処理方法において、前記硝化工程におけるモリブデン濃度を、前記被処理水に対して2mgMo/L以下とすることが好ましい。   In the water treatment method, the concentration of molybdenum in the nitrification step is preferably 2 mg Mo / L or less with respect to the water to be treated.

前記水処理方法において、前記被処理水中の窒素濃度が、100mgN/L以上であることが好ましい。   In the water treatment method, the nitrogen concentration in the water to be treated is preferably 100 mg N / L or more.

前記水処理方法において、前記微生物活性汚泥中に含まれる脱窒菌により、前記硝化工程で生成した亜硝酸または硝酸態窒素を窒素ガスにまで還元する脱窒工程をさらに含むことが好ましい。   The water treatment method preferably further includes a denitrification step of reducing nitrous acid or nitrate nitrogen generated in the nitrification step to nitrogen gas by denitrifying bacteria contained in the microorganism-activated sludge.

前記水処理方法における前記脱窒工程において、処理水の水理学的滞留時間における水素供与体の最大濃度と最小濃度との差が、50mgTOC/L以上となるように、前記水素供与体の添加量に時間変動を与えることによって、前記硝化菌と脱窒菌とを含む微生物活性汚泥をグラニュール化させることが好ましい。 In the denitrifying step in the water treatment method, the addition amount of the hydrogen donor such that the difference between the maximum concentration and the minimum concentration of the hydrogen donor in the hydraulic retention time of the treated water is 50 mg TOC / L or more in the Rukoto allow time variation, it is preferred that the microbial activity sludge is granulated comprising said nitrifying bacteria and denitrifying bacteria.

前記水処理方法において、前記脱窒工程は、少なくとも第一脱窒工程と第二脱窒工程とを含み、前記脱窒工程において、前記第二脱窒工程における処理水の水理学的滞留時間における前記第一脱窒工程における水素供与体の最大濃度と前記第二脱窒工程における水素供与体の最小濃度との差が、50mgTOC/L以上となるように、少なくとも前記第一脱窒工程において水素供与体を供給することが好ましい。   In the water treatment method, the denitrification step includes at least a first denitrification step and a second denitrification step, and in the denitrification step, the hydraulic retention time of the treated water in the second denitrification step Hydrogen in at least the first denitrification step such that the difference between the maximum concentration of the hydrogen donor in the first denitrification step and the minimum concentration of the hydrogen donor in the second denitrification step is 50 mg TOC / L or more It is preferred to supply a donor.

また、本発明は、アンモニア態窒素および有機態窒素を含む被処理水を、生物学的に処理する水処理装置であって、微生物活性汚泥中に含まれる独立栄養性のアンモニア酸化菌と亜硝酸酸化菌とを含む硝化菌により、前記アンモニア態窒素を亜硝酸または硝酸態窒素にまで酸化する硝化手段を備え、前記硝化手段において、前記被処理水に対して、モリブデン濃度が0.025mgMo/gN以上となるようにモリブデン化合物を存在させ、汚泥あたりの硝化速度が、0.11[kgN/(kgVSS・日)]以上である、水処理装置である。 Further, the present invention is a water treatment apparatus for biologically treating treated water containing ammonia nitrogen and organic nitrogen, which is an autotrophic ammonia oxidizing bacterium contained in microbial activated sludge and nitrite. The method comprises nitrification means for oxidizing the ammonia nitrogen to nitrite or nitrate nitrogen by nitrifying bacteria containing oxidizing bacteria, and the nitrification means comprises a molybdenum concentration of 0.025 mg Mo / g N with respect to the water to be treated. in the presence of a molybdenum compound such that the above, nitrification speed of the sludge, Ru der 0.11 [kgN / (kgVSS · day)] or more, a water treatment device.

前記水処理装置において、前記硝化手段におけるモリブデン濃度を、前記被処理水に対して2mgMo/L以下とすることが好ましい。   In the water treatment apparatus, the concentration of molybdenum in the nitrification means is preferably 2 mg Mo / L or less with respect to the water to be treated.

前記水処理装置において、前記被処理水中の窒素濃度が、100mgN/L以上であることが好ましい。   In the said water treatment apparatus, it is preferable that the nitrogen concentration in the said to-be-processed water is 100 mgN / L or more.

前記水処理装置において、前記微生物活性汚泥中に含まれる脱窒菌により、前記硝化手段で生成した亜硝酸または硝酸態窒素を窒素ガスにまで還元する脱窒手段をさらに備えることが好ましい。   The water treatment apparatus preferably further comprises denitrification means for reducing nitrous acid or nitrate nitrogen produced by the nitrification means to nitrogen gas by denitrifying bacteria contained in the microorganism-activated sludge.

前記水処理装置における前記脱窒手段において、処理水の水理学的滞留時間における水素供与体の最大濃度と最小濃度との差が、50mgTOC/L以上となるように、前記水素供与体の添加量に時間変動を与えることによって、前記硝化菌と脱窒菌とを含む微生物活性汚泥をグラニュール化させることが好ましい。 In the denitrifying means in the water treatment apparatus, the addition amount of the hydrogen donor such that the difference between the maximum concentration and the minimum concentration of the hydrogen donor in the hydraulic retention time of the treated water is 50 mg TOC / L or more in the Rukoto allow time variation, it is preferred that the microbial activity sludge is granulated comprising said nitrifying bacteria and denitrifying bacteria.

前記水処理装置において、前記脱窒手段は、少なくとも第一脱窒手段と第二脱窒手段とを備え、前記脱窒手段において、前記第二脱窒手段における処理水の水理学的滞留時間における前記第一脱窒手段における水素供与体の最大濃度と前記第二脱窒手段における水素供与体の最小濃度との差が、50mgTOC/L以上となるように、少なくとも前記第一脱窒手段において水素供与体を供給することが好ましい。   In the water treatment apparatus, the denitrification means comprises at least a first denitrification means and a second denitrification means, and in the denitrification means, a hydraulic residence time of treated water in the second denitrification means Hydrogen in at least the first denitrification means such that the difference between the maximum concentration of hydrogen donors in the first denitrification means and the minimum concentration of hydrogen donors in the second denitrification means is 50 mg TOC / L or more It is preferred to supply a donor.

本発明により、アンモニア態窒素および有機態窒素を含む被処理水の生物学的処理において、被処理水中の窒素濃度が高濃度であっても高い処理速度で安定して処理することができる。   According to the present invention, in biological treatment of treated water containing ammonia nitrogen and organic nitrogen, stable treatment can be carried out at a high treatment rate even if the nitrogen concentration in the treated water is high.

本発明の実施形態に係る水処理装置の一例を示す概略構成図である。It is a schematic block diagram which shows an example of the water treatment apparatus which concerns on embodiment of this invention. 本発明の実施形態に係る水処理装置の他の例を示す概略構成図である。It is a schematic block diagram which shows the other example of the water treatment apparatus which concerns on embodiment of this invention. 本発明の実施形態に係る水処理装置の他の例を示す概略構成図である。It is a schematic block diagram which shows the other example of the water treatment apparatus which concerns on embodiment of this invention. 本発明の実施形態に係る水処理装置の他の例を示す概略構成図である。It is a schematic block diagram which shows the other example of the water treatment apparatus which concerns on embodiment of this invention. 本発明の実施形態に係る水処理装置の他の例を示す概略構成図である。It is a schematic block diagram which shows the other example of the water treatment apparatus which concerns on embodiment of this invention. 実施例1および比較例1における、経過日数[day]に対する硝化槽容積負荷[kgN/(m・d)]、硝化槽のアンモニア態窒素濃度[mgN/L]を示すグラフである。It is a graph which shows the nitrification tank volume load [kgN / (m 3 · d)] and ammonia nitrogen concentration [mgN / L] of the nitrification tank with respect to elapsed days [day] in Example 1 and Comparative Example 1. 実施例1および比較例1における、経過日数[day]に対する脱窒槽容積負荷[kgN/(m・d)]、処理水の総窒素濃度[mgN/L]を示すグラフである。It is a graph which shows denitrification tank volume load [kgN / (m 3 d)] to total days [day] in Example 1 and comparative example 1, and total nitrogen concentration [mgN / L] of treated water. 比較例2における、経過日数[day]に対する硝化槽容積負荷[kgN/(m・d)]、硝化槽のアンモニア態窒素濃度[mgN/L]を示すグラフである。It is a graph which shows the nitrification tank volume load [kgN / (m 3 · d)] and ammonia nitrogen concentration [mgN / L] of the nitrification tank with respect to elapsed days [day] in Comparative Example 2. 比較例2における、経過日数[day]に対する脱窒槽容積負荷[kgN/(m・d)]、処理水の総窒素濃度[mgN/L]を示すグラフである。It is a graph which shows denitrification tank volume load [kgN / (m 3 d)] to total days [day] in comparative example 2, and total nitrogen concentration [mgN / L] of treated water. 実施例2における、経過日数[day]に対する硝化槽容積負荷[kgN/(m・d)]、硝化槽のアンモニア態窒素濃度[mgN/L]を示すグラフである。It is a graph which shows the nitrification tank volume load [kgN / (m 3 d)] and ammonia nitrogen concentration [mgN / L] of a nitrification tank with respect to elapsed days [day] in Example 2. 実施例2における、経過日数[day]に対する脱窒槽容積負荷[kgN/(m・d)]、処理水の総窒素濃度[mgN/L]を示すグラフである。In Example 2, it is a graph which shows the denitrification tank volume load [kgN / (m 3 d)] to the lapsed days [day], and the total nitrogen concentration [mgN / L] of treated water. 実施例3における、経過日数[day]に対する硝化槽容積負荷[kgN/(m・d)]、硝化槽のアンモニア態窒素濃度[mgN/L]を示すグラフである。In Example 3, it is a graph which shows the nitrification tank volume load [kgN / (m 3 · d)] to the elapsed days [day], and the ammoniacal nitrogen concentration [mgN / L] of the nitrification tank. 実施例3における、経過日数[day]に対する脱窒槽容積負荷[kgN/(m・d)]、処理水の総窒素濃度[mgN/L]を示すグラフである。In Example 3, it is a graph which shows the denitrification tank volume load [kgN / (m 3 d)] to the lapse days [day], and the total nitrogen concentration [mgN / L] of treated water. 実施例におけるモリブデン濃度(Mo/N[mg/g])に対する硝化速度[kgN/(kgVSS・d)]を示すグラフである。It is a graph which shows the nitrification rate [kgN / (kgVSS * d)] to the molybdenum concentration (Mo / N [mg / g]) in an example.

本発明の実施の形態について以下説明する。本実施形態は本発明を実施する一例であって、本発明は本実施形態に限定されるものではない。   Embodiments of the present invention will be described below. The present embodiment is an example for implementing the present invention, and the present invention is not limited to the present embodiment.

本発明の実施形態に係る水処理装置の一例の概略を図1に示し、その構成について説明する。   An outline of an example of a water treatment apparatus according to an embodiment of the present invention is shown in FIG. 1, and the configuration thereof will be described.

水処理装置1は、アンモニア態窒素および有機態窒素を含む被処理水を、生物学的に処理する水処理装置であって、微生物活性汚泥中に含まれる独立栄養性のアンモニア酸化菌と亜硝酸酸化菌とを含む硝化菌により、アンモニア態窒素を亜硝酸または硝酸態窒素にまで酸化する硝化手段として、硝化装置10を備え、硝化装置10において、被処理水に対して、モリブデン濃度が0.025mgMo/gN以上となるようにモリブデン化合物を存在させる装置である。水処理装置1は、微生物活性汚泥中に含まれる脱窒菌により、硝化装置10で生成した亜硝酸または硝酸態窒素を窒素ガスにまで還元する脱窒手段として、脱窒装置12をさらに備えてもよい。   The water treatment apparatus 1 is a water treatment apparatus that biologically treats treated water containing ammonia nitrogen and organic nitrogen, and is an autotrophic ammonia oxidizing bacterium and nitrite contained in microorganism activated sludge A nitrification device 10 is provided as a nitrification means for oxidizing ammoniacal nitrogen to nitrite or nitrate nitrogen by nitrifying bacteria containing oxidizing bacteria, and the nitrification device 10 has a molybdenum concentration of 0. 0 to the water to be treated. It is an apparatus in which a molybdenum compound is made to be 025 mgMo / gN or more. The water treatment apparatus 1 further comprises a denitrification device 12 as a denitrification means for reducing nitrite or nitrate nitrogen produced by the nitrification device 10 to nitrogen gas by denitrifying bacteria contained in the microorganism activated sludge. Good.

水処理装置1は、微生物活性汚泥から処理水を分離して処理水を得る固液分離手段として、固液分離装置14と、固液分離装置14で分離された汚泥を固液分離装置14の前段へ返送する返送手段として、汚泥返送配管24とをさらに備えてもよい。   The water treatment apparatus 1 is a solid-liquid separation device 14 and solid-liquid separation device 14 separated from solid-liquid separation device 14 as solid-liquid separation means for separating treated water from microbial activated sludge and obtaining treated water. You may further provide the sludge return piping 24 as a return means returned to a front | former stage.

図1の水処理装置1において、硝化装置10の入口には、配管16が接続され、硝化装置10の出口と脱窒装置12の入口とは、配管18により接続され、脱窒装置12の出口と固液分離装置14の入口とは、配管20により接続され、固液分離装置14の処理水出口には、配管22が接続され、固液分離装置14の汚泥出口と配管16とは、汚泥返送配管24により接続されている。配管16には、モリブデン化合物供給配管26が接続され、脱窒装置12には、水素供与体供給配管28が接続されている。   In the water treatment apparatus 1 of FIG. 1, the pipe 16 is connected to the inlet of the nitrification apparatus 10, the outlet of the nitrification apparatus 10 and the inlet of the denitrification apparatus 12 are connected by the pipe 18, and the outlet of the denitrification apparatus 12 And the inlet of the solid-liquid separator 14 are connected by a pipe 20, the pipe 22 is connected to the treated water outlet of the solid-liquid separator 14, the sludge outlet of the solid-liquid separator 14 and the pipe 16 are sludge It is connected by return piping 24. A molybdenum compound supply pipe 26 is connected to the pipe 16, and a hydrogen donor supply pipe 28 is connected to the denitrification device 12.

本実施形態に係る水処理方法および水処理装置1の動作について説明する。   The operation of the water treatment method and the water treatment apparatus 1 according to the present embodiment will be described.

アンモニア態窒素および有機態窒素を含む被処理水は、配管16を通して、硝化装置10へ送液される。硝化装置10において、微生物活性汚泥中に含まれる独立栄養性のアンモニア酸化菌と亜硝酸酸化菌とを含む硝化菌により、被処理水に含まれるアンモニア態窒素が亜硝酸または硝酸態窒素にまで酸化される(硝化工程)。ここで、配管16において、被処理水に対して、モリブデン化合物供給配管26を通してモリブデン化合物が供給され、モリブデン濃度が0.025mgMo/gN以上となるようにモリブデン化合物を存在させる(モリブデン化合物供給工程)。硝化液は、配管18を通して、脱窒装置12へ送液される。   Water to be treated containing ammonia nitrogen and organic nitrogen is sent to the nitrification device 10 through the pipe 16. In the nitrification apparatus 10, ammonia nitrogen contained in the water to be treated is oxidized to nitrite or nitrate nitrogen by nitrification bacteria including autotrophic ammonia oxidizing bacteria and nitrite oxidizing bacteria contained in the microorganism activated sludge (Nitrification process). Here, in the pipe 16, the molybdenum compound is supplied to the water to be treated through the molybdenum compound supply pipe 26, and the molybdenum compound is made to have a molybdenum concentration of 0.025 mg Mo / gN or more (molybdenum compound supply step) . The nitrification liquid is sent to the denitrifying device 12 through the pipe 18.

脱窒装置12において、水素供与体供給配管28を通して水素供与体が供給され、微生物活性汚泥中に含まれる従属栄養性の脱窒菌により、硝化装置10(硝化工程)で生成した亜硝酸または硝酸態窒素が窒素ガスにまで還元される(脱窒工程)。脱窒液は、配管20を通して、固液分離装置14へ送液される。   In the denitrification apparatus 12, the hydrogen donor is supplied through the hydrogen donor supply pipe 28, and nitrous acid or nitrate formed in the nitrification apparatus 10 (nitrification process) by heterotrophic denitrifying bacteria contained in the microorganism activated sludge Nitrogen is reduced to nitrogen gas (denitrification step). The denitrifying solution is sent to the solid-liquid separator 14 through the pipe 20.

固液分離装置14において、脱窒液の微生物活性汚泥から処理水が分離されて処理水が得られる(固液分離工程)。固液分離により得られた処理水は、配管22を通して排出される。一方、固液分離により得られた汚泥の少なくとも一部は、汚泥返送配管24を通して、配管16へ返送されて、被処理水と混合される。汚泥は、固液分離装置14(固液分離工程)の前段へ返送されればよく、例えば、硝化装置10、脱窒装置12へ返送されてもよく、配管18,20へ返送されてもよい。固液分離により得られた汚泥の少なくとも一部は、固液分離装置14から系外へ排出されてもよい。   In the solid-liquid separation device 14, the treated water is separated from the microorganism activated sludge of the denitrifying liquid to obtain treated water (solid-liquid separation step). The treated water obtained by solid-liquid separation is discharged through the pipe 22. On the other hand, at least a part of the sludge obtained by the solid-liquid separation is returned to the pipe 16 through the sludge return pipe 24 and mixed with the water to be treated. The sludge may be returned to the previous stage of the solid-liquid separation device 14 (solid-liquid separation step), for example, may be returned to the nitrification device 10 and the denitrification device 12 or may be returned to the pipes 18 and 20 . At least a part of the sludge obtained by solid-liquid separation may be discharged from the solid-liquid separation device 14 out of the system.

本発明者らは、アンモニア態窒素および有機態窒素を含む窒素含有被処理水、特に被処理水中の窒素濃度が例えば100mgN/L以上のような高濃度の窒素含有被処理水を、独立栄養性のアンモニア酸化菌と亜硝酸酸化菌とを含む硝化菌を含む微生物活性汚泥を用いて処理する方法において、微生物の代謝活性が低下してしまい、処理速度が低下した場合において、被処理水に対してモリブデン濃度が0.025mgMo/gN以上となるようにモリブデン化合物を存在させることで、硝化菌の代謝活性が大幅に回復、さらには向上し、安定して高い処理速度を得ることが可能となることを見出した。また、本発明者らは、アンモニア態窒素および有機態窒素を含む窒素含有被処理水、特に被処理水中の窒素濃度が例えば100mgN/L以上のような高濃度の窒素含有被処理水を、独立栄養性のアンモニア酸化菌と亜硝酸酸化菌とを含む硝化菌および従属栄養性の脱窒菌を含む微生物活性汚泥を用いて処理する方法において、微生物の代謝活性が低下してしまい、処理速度が低下した場合において、被処理水に対してモリブデン濃度が0.025mgMo/gN以上となるようにモリブデン化合物を存在させることで、硝化菌および脱窒菌の代謝活性が大幅に回復、さらには向上し、安定して高い処理速度を得ることが可能となることを見出した。   The present inventors are autotrophic for nitrogen-containing treated water containing ammonia nitrogen and organic nitrogen, particularly high concentration nitrogen-containing treated water having a nitrogen concentration of, for example, 100 mg N / L or more in the treated water. In the method of treating with microbial activated sludge containing nitrifying bacteria containing ammonia oxidizing bacteria and nitrite oxidizing bacteria of the present invention, the metabolic activity of the microorganism is lowered and the treatment speed is lowered, relative to the water to be treated By the presence of the molybdenum compound so that the molybdenum concentration is 0.025 mg Mo / gN or more, the metabolic activity of the nitrifying bacteria is significantly recovered and further improved, and it becomes possible to obtain a stable high processing speed. I found out. The present inventors have also independently isolated nitrogen-containing treated water containing ammonia nitrogen and organic nitrogen, particularly nitrogen-containing treated water having a high concentration of, for example, 100 mg N / L or more in the treated water. In the method of treating with microorganism activated sludge containing nitrifying bacteria containing heterotrophic ammonia oxidizing bacteria and nitrite oxidizing bacteria and heterotrophic denitrifying bacteria, the metabolic activity of the microorganism is reduced and the treatment speed is lowered. In such a case, the metabolic activity of the nitrifying bacteria and the denitrifying bacteria is greatly recovered, further improved, and stabilized by the presence of the molybdenum compound so that the molybdenum concentration is 0.025 mg Mo / gN or more relative to the water to be treated. It has been found that it is possible to obtain a high processing speed.

窒素含有被処理水、特に高濃度の窒素含有被処理水の生物学的処理において、モリブデン化合物により、微生物活性汚泥中のアンモニア酸化菌および亜硝酸酸化菌を含む硝化菌の活性を向上させることにより、被処理水中の窒素濃度が高濃度であっても高い処理速度で安定して処理することができる。また、窒素含有被処理水、特に高濃度の窒素含有被処理水の生物学的処理において、モリブデン化合物により、微生物活性汚泥中の脱窒菌の活性だけでなく、アンモニア酸化菌および亜硝酸酸化菌を含む硝化菌の活性をも向上させることにより、被処理水中の窒素濃度が高濃度であっても高い処理速度で安定して処理することができる。   In biological treatment of nitrogen-containing treated water, especially high-concentration nitrogen-containing treated water, the activity of nitrifying bacteria including ammonia oxidizing bacteria and nitrite oxidizing bacteria in microorganism activated sludge is improved with a molybdenum compound Even when the nitrogen concentration in the water to be treated is high, stable treatment can be performed at a high treatment rate. In addition, in biological treatment of nitrogen-containing treated water, especially high-concentration nitrogen-containing treated water, not only the activity of denitrifying bacteria in microbially activated sludge but also ammonia oxidizing bacteria and nitrite oxidizing bacteria with a molybdenum compound By improving the activity of the nitrifying bacteria contained, even when the nitrogen concentration in the water to be treated is high, stable treatment can be carried out at a high treatment rate.

一般的に、排水の生物学的処理を行う場合において微生物の増殖および代謝反応を維持するために、被処理水中の栄養素バランスを保つ必要がある。細胞の構成成分としての栄養素として「生物親元素」と言われる炭素(C)、酸素(O)、窒素(N)、水素(H)、リン(P)は必須成分となる。その他、生物親元素よりは比較的要求量は少ないが、硫黄(S)、カリウム(K)、ナトリウム(Na)、カルシウム(Ca)、マグネシウム(Mg)、塩素(Cl)、鉄(Fe)も細胞構成要素として必要な成分であるため、被処理水中の各種元素の含有量が少ない場合、それらを添加補給することが好ましい。一方で、要求量は少ないが、微生物の酵素代謝に関与する微量元素も存在した方がよく、例えば、フッ素(F)、シリカ(Si)、バナジウム(V)、クロム(Cr)、マンガン(Mn)、コバルト(Co)、ニッケル(Ni)、銅(Cu)、亜鉛(Zn)、ヒ素(As)、セレン(Se)、モリブデン(Mo)、ヨウ素(I)等が挙げられる。しかし、これら重金属類を含む微量元素類は、要求量が非常に微量であり、被処理水中に必要十分な量が存在していると想定されていることから、通常、外部から被処理水や処理系内に添加するようなことはない。一方で、半導体産業等の超純水を使用する工場から排出される排水を生物学的に処理する際に、上記のような微量元素類が不足していると想定される場合は、被処理水に水道水や、工業用水、井水等を混合することで補給する場合がある。しかし被処理水中の窒素濃度が比較的高い(例えば100mgN/L以上)場合、硝化速度が低下してしまうことがある。このような状態であっても、本実施形態に係る水処理方法および水処理装置では、モリブデン化合物を処理系内に所定量供給することで、処理の安定化、高速処理が可能となる。   In general, it is necessary to maintain nutrient balance in treated water in order to maintain the growth and metabolic reaction of microorganisms in biological treatment of waste water. Carbon (C), oxygen (O), nitrogen (N), hydrogen (H), and phosphorus (P), which are said to be "bioparental elements" as nutrients as constituent components of cells, are essential components. In addition, sulfur (S), potassium (K), sodium (Na), calcium (Ca), magnesium (Mg), chlorine (Cl), iron (Fe) are required although the requirement is relatively less than biophilic elements. Since it is a component necessary as a cell component, when the content of various elements in the water to be treated is small, it is preferable to add and replenish them. On the other hand, although the amount required is small, it is better that trace elements involved in the enzyme metabolism of microorganisms should also be present, for example, fluorine (F), silica (Si), vanadium (V), chromium (Cr), manganese (Mn) And cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), molybdenum (Mo), iodine (I) and the like. However, trace elements including these heavy metals are required to be very small in amount, and it is assumed that a necessary and sufficient amount is present in the water to be treated. There is no such thing added in the treatment system. On the other hand, when it is assumed that the above trace elements are insufficient when biologically treating wastewater discharged from a factory using ultrapure water, such as the semiconductor industry, it is possible to treat the wastewater Water may be replenished by mixing tap water, industrial water, well water, etc. with water. However, when the nitrogen concentration in the water to be treated is relatively high (for example, 100 mgN / L or more), the nitrification rate may be reduced. Even in such a state, in the water treatment method and the water treatment apparatus according to the present embodiment, stabilization of the treatment and high-speed treatment can be performed by supplying a predetermined amount of the molybdenum compound into the treatment system.

被処理水中の窒素成分の処理に関る反応は、主に以下に分けられる。
1.NH →NO (アンモニア酸化菌)
2.NO →NO (亜硝酸酸化菌)
3.NO →N(脱窒菌)
The reactions involved in the treatment of the nitrogen component in the water to be treated are mainly divided into the following.
1. NH 4 + → NO 2 - (ammonia oxidation bacteria)
2. NO 2 - → NO 3 - (nitrite-oxidizing bacteria)
3. NO 3 -N 2 (denitrifying bacteria)

脱窒菌による、無酸素条件下における硝酸の異化的還元反応(硝酸呼吸)に関しては、生化学的な検討が進められている。例えば、非特許文献2によれば、硝酸から窒素ガスまでの反応は、[NO →NO →NO→NO→N]に細分化され、[NO →NO ]の還元反応を触媒する酵素は、モリブデン元素が関与していることが明らかとなっている。つまり、排水処理系における脱窒反応に関して、必要量の程度は明らかとなってはいないが、モリブデン化合物を添加することでその活性が向上することが想定される。 Biochemical studies are underway on the catabolic reductive reaction (nitric acid respiration) of nitric acid under anoxic conditions by denitrifying bacteria. For example, according to Non-Patent Document 2, the reaction from nitric acid to nitrogen gas is subdivided into [NO 3 → NO 2 → NO → N 2 O → N 2 ], and [NO 3 → NO 2 It has been clarified that the element which catalyzes the reduction reaction of [. That is, regarding the denitrification reaction in the waste water treatment system, although the required amount is not clear, it is assumed that the activity is improved by adding the molybdenum compound.

また、亜硝酸酸化菌が亜硝酸を酸化する際にモリブデンを要求することが研究により解明されている。例えば、非特許文献3では、亜硝酸酸化菌であるNitrobacterの培養条件を検討しており、少なくとも、10−9Mのモリブデン添加により、Nitrobacterによる亜硝酸の利用および細胞増殖が11倍上昇したことが示されている。つまり、排水処理系における亜硝酸酸化反応に関しては、モリブデン化合物を添加することでその活性が向上することが想定される。 In addition, research has revealed that nitrite oxidizing bacteria require molybdenum when oxidizing nitrite. For example, Non-patent Document 3 examines the culture conditions of Nitrobacter, a nitrite-oxidizing bacterium, and that addition of at least 10 -9 M molybdenum resulted in an 11-fold increase in nitrous acid utilization and cell proliferation by Nitrobacter. It is shown. That is, regarding the nitrite oxidation reaction in the waste water treatment system, it is assumed that the activity is improved by adding the molybdenum compound.

一方で、アンモニア酸化菌のアンモニア酸化代謝に関わる酵素としては、アンモニアを酸化し、ヒドロキシルアミンを生成するammonium monooxygenase (AMO)および、生成したヒドロキシルアミンからさらに亜硝酸を生成するhydroxylamine oxidoreductase(HAO)の2種類の酵素が関与しているとされているが、これらはモリブデンが関与する酵素反応であるという報告はない(非特許文献4参照)。   On the other hand, among enzymes involved in the ammonia oxidation metabolism of ammonia oxidizing bacteria, ammonia monooxygenase (AMO) which oxidizes ammonia to produce hydroxylamine and hydroxylamine oxidoreductase (HAO) which further produces nitrite from the produced hydroxylamine. Although two types of enzymes are considered to be involved, there is no report that these are enzyme reactions involving molybdenum (see Non-Patent Document 4).

特許文献1には、効率的に硝化反応を進めるために、コバルトを被処理水に共存させるとともに、さらにモリブデン、カルシウム、マグネシウム成分を共存させる方法が記載されている。特許文献1の実施例で、窒素濃度として70mgN/Lという比較的低濃度の被処理水の硝化脱窒処理試験を、モリブデン濃度として1mgMo/L共存下(14.3mgMo/gN)で検証しており、硝化の汚泥負荷が2.5gN/(kgMLSS・時)[=0.06kgN/(kgMLSS・日)]の条件にて、窒素の除去率が90%になるという結果を得ているが、顕著な効果が得られたとは考えにくい。   Patent Document 1 describes a method of causing cobalt to coexist with water to be treated and further causing a molybdenum, calcium, and magnesium component to coexist in order to efficiently promote the nitrification reaction. In the example of Patent Document 1, a nitrification denitrification test of a relatively low concentration water to be treated with a nitrogen concentration of 70 mg N / L is verified under the coexistence of 1 mg Mo / L as a molybdenum concentration (14.3 mg Mo / g N) The result shows that the removal rate of nitrogen is 90% under the condition that the sludge load of nitrification is 2.5gN / (kgMLSS.h) [= 0.06kgN / (kgMLSS.day)]. It is hard to believe that a remarkable effect was obtained.

本発明者らは、アンモニア酸化菌および亜硝酸酸化菌が共存する微生物活性汚泥を用いて、特に高濃度の窒素を含有する被処理水を処理する方法において、モリブデンを所定量供給することで、亜硝酸酸化反応のみならず、アンモニア酸化菌の活性をも大幅に向上させることができることを見出した。また、本発明者らは、アンモニア酸化菌および亜硝酸酸化菌、脱窒菌を含む様々な細菌類が共存する微生物活性汚泥を用いて、特に高濃度の窒素を含有する被処理水を処理する方法において、モリブデンを所定量供給することで、亜硝酸酸化や脱窒(硝酸還元)反応のみならず、アンモニア酸化菌の活性をも大幅に向上させることができることを見出した。アンモニア酸化菌および亜硝酸酸化菌のような独立栄養性細菌と、有機物を資化可能な脱窒菌のような従属栄養性細菌が共存した微生物活性汚泥中では、増殖速度が硝化菌よりも大きい脱窒菌を含む従属栄養性細菌が汚泥中で優占している。通常、各細菌の代謝反応は独立していると想定されるが、複数の機能微生物が存在する微生物活性汚泥中では、各細菌が共存関係にある。モリブデン化合物添加がアンモニア酸化活性を向上させる機構は明らかではないが、脱窒菌のような従属栄養性細菌の代謝活性をモリブデンの供給により、増加させることができることから、相対的にアンモニア酸化の活性向上にも繋がっていると推察される。   The present inventors use a microorganism activated sludge in which ammonia oxidizing bacteria and nitrite oxidizing bacteria coexist, in particular, by supplying a predetermined amount of molybdenum in a method of treating water to be treated containing nitrogen at a high concentration, It has been found that not only the nitrite oxidation reaction but also the activity of ammonia oxidizing bacteria can be greatly improved. Moreover, the present inventors are a method of treating treated water containing particularly high concentration of nitrogen using microorganism activated sludge in which various bacteria including ammonia oxidizing bacteria, nitrite oxidizing bacteria, and denitrifying bacteria coexist. In the above, it was found that by supplying a predetermined amount of molybdenum, not only nitrite oxidation and denitrification (nitrate reduction) reactions but also the activity of ammonia oxidizing bacteria can be greatly improved. In microbially activated sludge in which autotrophic bacteria such as ammonia oxidizing bacteria and nitrite oxidizing bacteria coexist with heterotrophic bacteria such as denitrifying bacteria capable of assimilating organic matter, the growth rate is higher than that of nitrifying bacteria Heterotrophic bacteria, including asphyxial bacteria, are predominant in the sludge. Usually, it is assumed that the metabolic reaction of each bacterium is independent, but in the microorganism activated sludge in which a plurality of functional microorganisms exist, each bacterium is in a co-relationship. Although the mechanism by which the addition of the molybdenum compound improves the ammonia oxidation activity is not clear, the metabolic activity of heterotrophic bacteria such as denitrifying bacteria can be increased by the supply of molybdenum, so the activity of ammonia oxidation is relatively improved relatively It is guessed that it is connected.

本実施形態において、処理対象となる被処理水は、アンモニア態窒素を含む窒素含有水であり、特に、アンモニア態窒素を高濃度に含む窒素含有水であり、さらに有機態窒素を含む。被処理水としては、例えば、電子産業排水、金属精錬工場排水、発電所排水等の産業排水や、汚泥処理過程で排出される消化脱離水を含む排水等が挙げられる。ここで、電子産業排水は、様々な薬品が含まれており、また、製造する製品によっても排水中の成分は大きく異なるが、窒素含有水としては、例えばウェハー洗浄排水等が挙げられる。この排水中には、アンモニアの他、水酸化テトラメチルアンモニウム(TMAH)、過酸化水素、フッ素イオン、イソプロピルアルコール(IPA)等を含むことが多い。   In the present embodiment, the water to be treated is nitrogen-containing water containing ammonia nitrogen, particularly nitrogen-containing water containing ammonia nitrogen at a high concentration, and further contains organic nitrogen. Examples of the water to be treated include industrial waste water such as electronic industrial waste water, metal smelting plant waste water, and power plant waste water, and waste water containing digestion and desorption water discharged in the sludge treatment process. Here, the electronic industrial waste water contains various chemicals, and although the components in the waste water greatly vary depending on the products to be manufactured, examples of the nitrogen-containing water include wafer cleaning waste water and the like. In addition to ammonia, tetramethylammonium hydroxide (TMAH), hydrogen peroxide, fluorine ions, isopropyl alcohol (IPA) and the like are often contained in the waste water.

被処理水中のモリブデン濃度は、例えば、0.0001mgMo/L以下である。また、被処理水中の窒素濃度が、好ましくは100mgN/L以上である場合、より好ましくは400mgN/L以上である場合に、本実施形態に係る水処理方法および水処理装置が好適に適用される。   The molybdenum concentration in the water to be treated is, for example, 0.0001 mg Mo / L or less. Further, when the nitrogen concentration in the water to be treated is preferably 100 mg N / L or more, more preferably 400 mg N / L or more, the water treatment method and the water treatment apparatus according to the present embodiment are suitably applied. .

このような窒素含有水を生物学的に処理するにあたり、過酸化水素やフッ素イオン等の阻害性物質は生物に対して阻害性を有するため、予め除去することが望ましい。これらの阻害性物質の処理方法としては、既存技術を使用することができ、例えば、過酸化水素の処理においては、酵素を添加する方法、還元剤を注入する方法、活性炭に接触させる方法等が挙げられる。また、フッ素イオンの処理においては、カルシウムを添加してフッ化カルシウムとして除去する方法、イオン交換樹脂にて処理する方法等が挙げられる。   In biological treatment of such nitrogen-containing water, it is desirable to remove in advance inhibitory substances such as hydrogen peroxide and fluorine ions, because they have inhibitory properties to organisms. As a method of treating these inhibitory substances, existing techniques can be used. For example, in the treatment of hydrogen peroxide, a method of adding an enzyme, a method of injecting a reducing agent, a method of contacting activated carbon, etc. It can be mentioned. Moreover, in the process of a fluorine ion, the method of adding calcium and removing as calcium fluoride, the method of processing with ion exchange resin, etc. are mentioned.

過酸化水素やフッ素イオン等の阻害性物質を除去した窒素含有水は、生物学的処理工程による処理が行われる前に、一旦水槽に貯められ、生物学的処理工程にかかる流量や水質を安定化させるとともに、アルカリまたは酸等のpH調整剤により適切なpH(例えば、pH6.5〜8.0)に調整されることが好ましい。そして、流量、水質、pH等が調整された窒素含有水(被処理水)が生物学的処理工程に送られる。   Nitrogen-containing water from which inhibitory substances such as hydrogen peroxide and fluoride ions have been removed is temporarily stored in a water tank before treatment by the biological treatment process, and the flow rate and water quality required for the biological treatment process are stabilized. It is preferable that the pH be adjusted to an appropriate pH (for example, pH 6.5 to 8.0) by a pH adjuster such as alkali or acid. Then, nitrogen-containing water (water to be treated) whose flow rate, water quality, pH and the like are adjusted is sent to the biological treatment step.

硝化装置10における硝化工程は、硝化部(例えば硝化槽)に被処理水を供給して、被処理水中のアンモニウムイオン等のアンモニア態窒素を好気的(例えば酸素の存在下で)に亜硝酸または硝酸態窒素にまで酸化する工程である。硝化部には例えば空気導入管が接続されており、硝化部内の被処理水に空気等の酸素含有気体を供給することができる構造となっている。そして、硝化部内で、硝化菌の働きにより、被処理水中のアンモニウムイオン等のアンモニア態窒素を亜硝酸または硝酸態窒素に硝化させる。ここで硝化菌とは、アンモニウムイオン等のアンモニア態窒素を亜硝酸イオンに酸化する独立栄養性のアンモニア酸化菌と、亜硝酸イオンを硝酸イオンに酸化する独立栄養性の亜硝酸酸化菌との総称のことをいう。   In the nitrification step of the nitrification apparatus 10, water to be treated is supplied to the nitrification unit (for example, a nitrification tank), and ammonia nitrogen such as ammonium ion in the water to be treated is aerobically (for example, in the presence of oxygen) nitrite Or oxidation to nitrate nitrogen. For example, an air introduction pipe is connected to the nitrification part, and it has a structure capable of supplying an oxygen-containing gas such as air to the water to be treated in the nitrification part. Then, in the nitrification section, ammonia nitrogen such as ammonium ion in the water to be treated is nitrified to nitrous acid or nitrate nitrogen by the function of the nitrifying bacteria. Here, nitrifying bacteria is a generic term of autotrophic ammonia oxidizing bacteria that oxidize ammonia nitrogen such as ammonium ion to nitrite ion, and autotrophic nitrite oxidizing bacteria that oxidize nitrite ion to nitrate ion. Say

被処理水中に含まれるモリブデンが不足する場合には、モリブデン化合物を外部添加すればよい。モリブデン化合物は、例えばモリブデン化合物溶液として、被処理水に対してモリブデン化合物供給配管26を通して供給されて、モリブデン化合物が被処理水に混合されることで系内に供給される。モリブデン化合物は例えば処理される窒素量に比例させて供給すればよい。モリブデン化合物を所定量供給することで、硝化菌(アンモニア酸化菌および亜硝酸酸化菌)および脱窒菌の活性を高く維持し、安定運転または高速処理が可能となる。   When the amount of molybdenum contained in the water to be treated is insufficient, a molybdenum compound may be externally added. The molybdenum compound is supplied, for example, as a molybdenum compound solution to the water to be treated through the molybdenum compound supply pipe 26, and the molybdenum compound is supplied to the system by being mixed with the water to be treated. The molybdenum compound may be supplied, for example, in proportion to the amount of nitrogen to be treated. By supplying a predetermined amount of a molybdenum compound, the activities of nitrifying bacteria (ammonia oxidizing bacteria and nitrite oxidizing bacteria) and denitrifying bacteria are maintained high, and stable operation or high-speed processing becomes possible.

モリブデン化合物としては、例えば、モリブデン酸ナトリウム、モリブデン酸カリウム、モリブデン酸アンモニウム等のモリブデン酸化合物等が挙げられる。モリブデン化合物の形態としては特に限定はないが、例えば溶液の状態であれば微生物活性汚泥中の細菌が利用しやすく、例えばモリブデン酸ナトリウムやモリブデン酸カリウム等の水溶液が予め調製されて添加されることが好ましい。   Examples of molybdenum compounds include molybdic acid compounds such as sodium molybdate, potassium molybdate, ammonium molybdate and the like. The form of the molybdenum compound is not particularly limited. For example, in the state of solution, bacteria in the microorganism activated sludge can be easily utilized, and for example, an aqueous solution such as sodium molybdate or potassium molybdate is prepared in advance and added. Is preferred.

モリブデン化合物の添加場所については、硝化処理が行われる前の配管16に供給されてもよいし、被処理水と微生物活性汚泥とが混合された硝化装置10に供給されてもよい。また、添加されたモリブデン化合物が返送汚泥として固液分離工程よりも前段に返送され、系内を循環することを考慮すれば、配管18や脱窒装置12にモリブデン化合物供給配管が接続されて供給されてもいい。   The addition site of the molybdenum compound may be supplied to the pipe 16 before the nitrification treatment is performed, or may be supplied to the nitrification device 10 in which the water to be treated and the microorganism activated sludge are mixed. Also, considering that the added molybdenum compound is returned as a return sludge to the previous stage of the solid-liquid separation step and circulated in the system, the molybdenum compound supply piping is connected to the piping 18 and the denitrifying device 12 for supply It may be done.

硝化装置10(硝化工程)において、被処理水に対して、モリブデン濃度が0.025mgMo/gN以上となるようにモリブデン化合物を存在させるが、モリブデン濃度が0.1mgMo/gN以上となるようにモリブデン化合物を存在させることが好ましい。モリブデン濃度の上限としては、特に制限はないが、例えば、0.25mgMo/gN以下である。硝化装置10(硝化工程)において、被処理水に対して、モリブデン濃度が0.025mgMo/gN未満となると、硝化菌(アンモニア酸化菌および亜硝酸酸化菌)および脱窒菌の活性維持効果が現れない場合がある。   In the nitrification apparatus 10 (nitrification process), a molybdenum compound is present such that the concentration of molybdenum is 0.025 mg Mo / gN or more with respect to the water to be treated, but the molybdenum concentration is 0.1 mg Mo / g N or more Preferably the compounds are present. The upper limit of the molybdenum concentration is not particularly limited, and is, for example, 0.25 mg Mo / gN or less. In the nitrification apparatus 10 (nitrification process), when the molybdenum concentration is less than 0.025 mg Mo / g N with respect to the water to be treated, the activity maintenance effect of nitrifying bacteria (ammonia oxidizing bacteria and nitrite oxidizing bacteria) and denitrifying bacteria does not appear There is a case.

硝化装置10(硝化工程)において、モリブデン濃度を、被処理水に対して2mgMo/L以下とすることが好ましい。モリブデン濃度を、被処理水に対して2mgMo/L超とすると、硝化反応が阻害を受ける場合がある。   In the nitrification apparatus 10 (nitrification process), the concentration of molybdenum is preferably 2 mg Mo / L or less with respect to the water to be treated. When the concentration of molybdenum is more than 2 mg Mo / L to the water to be treated, the nitrification reaction may be inhibited.

硝化部内には、微生物を担持させる担体が設置されていてもよい。微生物が担持される担体としては、特に限定されるものではないが、例えば、プラスチックやポリウレタン等の樹脂製等のものを利用することが好ましい。   In the nitrification section, a carrier for supporting a microorganism may be installed. The carrier on which the microorganism is supported is not particularly limited, but it is preferable to use, for example, a resin or the like such as plastic or polyurethane.

脱窒装置12における脱窒工程は、例えば、完全混合型の脱窒部(例えば脱窒槽)に水素供与体を供給し、硝化部にて生成された亜硝酸または硝酸態窒素を無酸素条件下にて窒素ガスにまで還元する工程である。脱窒部(例えば脱窒槽)内では、従属栄養性細菌である脱窒菌の働きにより、亜硝酸または硝酸態窒素が窒素ガスにまで還元されることとなる。脱窒部では、効率的に処理を行うために硝化液と微生物活性汚泥とを無酸素条件で混合させるための撹拌装置が設置されていることが好ましい。   In the denitrification step in the denitrification apparatus 12, for example, a hydrogen donor is supplied to a completely mixed denitrification unit (for example, a denitrification tank), and nitrous acid or nitrate nitrogen generated in the nitrification unit is subjected to oxygen-free conditions Reducing to nitrogen gas at In the denitrification unit (for example, denitrification tank), nitrous acid or nitrate nitrogen is reduced to nitrogen gas by the function of denitrifying bacteria which are heterotrophic bacteria. In the denitrifying section, in order to perform the treatment efficiently, it is preferable that a stirring device for mixing the nitrification liquid and the microorganism activated sludge under anoxic conditions is installed.

脱窒部内には、微生物を担持させる担体が設置されていてもよい。微生物が担持される担体としては、特に限定されるものではないが、プラスチックやポリウレタン等の樹脂製等のものを利用することが好ましい。   In the denitrifying unit, a carrier for supporting a microorganism may be installed. The carrier on which the microorganism is supported is not particularly limited, but it is preferable to use one made of a resin such as plastic or polyurethane.

本実施形態で用いられる、脱窒のための水素供与体は、例えばメタノール、エタノール、イソプロピルアルコール等のアルコール類、酢酸等の有機酸類、水素ガス、アセトン、グルコース、エチルメチルケトン、水酸化テトラメチルアンモニウム(TMAH)等のうち1つまたは複数が挙げられるが、これに限定されるものではなく、水素供与体として従来公知のもの全てを使用することができる。水素供与体として、被処理水中に含まれている有機物等を利用してもよい。   The hydrogen donors for denitrification used in this embodiment are, for example, alcohols such as methanol, ethanol and isopropyl alcohol, organic acids such as acetic acid, hydrogen gas, acetone, glucose, ethyl methyl ketone, tetramethyl hydroxide One or more of ammonium (TMAH) and the like can be mentioned, but it is not limited thereto, and all conventionally known hydrogen donors can be used. As the hydrogen donor, an organic substance or the like contained in the water to be treated may be used.

固液分離装置14における固液分離工程は、微生物活性汚泥内の硝化菌および脱窒菌により、窒素成分が、硝化および脱窒処理された脱窒液を、処理水と微生物活性汚泥とに分離し、処理水を得る工程である。   The solid-liquid separation process in the solid-liquid separation device 14 separates the denitrification liquid, which has been subjected to nitrification and denitrification treatment by the nitrifying bacteria and denitrifying bacteria in the microorganism activated sludge, into treated water and microorganism activated sludge. It is a process of obtaining treated water.

固液分離装置14としては、特に限定されるものではないが、例えば、沈降分離、加圧浮上、濾過、膜分離等の分離装置が挙げられる。固液分離工程では、処理水が得られるとともに、分離後の微生物活性汚泥も得られ、微生物活性汚泥は一部が余剰汚泥として系外に引き抜かれ、一部は例えば硝化装置10(硝化工程)へと返送されることで、系内の微生物活性汚泥量を維持することができる。   The solid-liquid separation device 14 is not particularly limited, and examples thereof include separation devices such as sedimentation separation, pressure flotation, filtration, and membrane separation. In the solid-liquid separation step, treated water is obtained, and the microorganism activated sludge after separation is also obtained, and a part of the microorganism activated sludge is drawn out as an excess sludge, and a part is, for example, a nitrification device 10 (nitrification step) The amount of microbial activated sludge in the system can be maintained by being returned to the

脱窒装置12にて水素供与体が添加されるが、脱窒処理後に水素供与体が残存し、処理水質が悪化することが懸念される場合には、脱窒装置12(脱窒工程)と固液分離装置14(固液分離工程)との間に水素供与体を好気的に処理するための酸化手段として酸化装置が設置されてもいい。   Although a hydrogen donor is added in the denitrification device 12, if there is a concern that the hydrogen donor will remain after denitrification treatment and the treated water quality may deteriorate, the denitrification device 12 (denitrification step) and Between the solid-liquid separation device 14 (solid-liquid separation step), an oxidation device may be installed as an oxidation means for aerobically treating the hydrogen donor.

このような形態の水処理装置の例を図2に示す。図2の水処理装置3において、脱窒装置12(脱窒工程)と固液分離装置14(固液分離工程)との間に酸化装置30を備える。脱窒装置12の出口と酸化装置30の入口とは、配管32により接続され、酸化装置30の出口と固液分離装置14の入口とは、配管34により接続されている。   An example of such a water treatment apparatus is shown in FIG. In the water treatment device 3 of FIG. 2, an oxidation device 30 is provided between the denitrification device 12 (denitrification step) and the solid-liquid separation device 14 (solid-liquid separation step). The outlet of the denitrifying device 12 and the inlet of the oxidizing device 30 are connected by a pipe 32, and the outlet of the oxidizing device 30 and the inlet of the solid-liquid separator 14 are connected by a pipe 34.

脱窒装置12(脱窒工程)で得られた脱窒液は、配管32を通して、酸化装置30へ送液される。酸化装置30における酸化工程は、酸化部(たとえば酸化槽)で水素供与体が好気的に処理される。酸化部(たとえば酸化槽)には、例えば、硝化部と同様に空気導入管が接続されており、酸化部内の被処理水に空気等の酸素含有気体を供給することができる構造となっている。   The denitrifying solution obtained by the denitrifying device 12 (the denitrifying step) is sent to the oxidizing device 30 through the pipe 32. In the oxidation process in the oxidizer 30, the hydrogen donor is treated aerobically in an oxidizer (for example, an oxidizer). For example, an air introduction pipe is connected to the oxidation unit (for example, the oxidation tank) similarly to the nitrification unit, and has a structure capable of supplying an oxygen-containing gas such as air to the water to be treated in the oxidation unit. .

酸化装置30において酸化処理された酸化処理液は、配管34を通して固液分離装置14へ送液され、以降、図1の水処理装置1と同様にして処理が行われる。   The oxidation treatment liquid oxidized in the oxidation device 30 is sent to the solid-liquid separator 14 through the pipe 34, and thereafter, the treatment is performed in the same manner as the water treatment device 1 of FIG.

被処理水に有機物と窒素を含む場合には、脱窒反応のための水素供与体を外部から添加することなく、被処理水中の有機物を水素供与体として脱窒反応を起こしてもいい。   When organic water and nitrogen are contained in the water to be treated, denitrification reaction may be caused by using the organic matter in the water to be treated as a hydrogen donor without externally adding a hydrogen donor for denitrification reaction.

このような形態の水処理装置の例を図3に示す。図3の水処理装置5において、脱窒装置12の入口には、配管36が接続され、脱窒装置12の出口と硝化装置10の入口とは、配管38により接続され、硝化装置10の出口と固液分離装置14の入口とは、配管40により接続され、固液分離装置14の処理水出口には、配管42が接続され、固液分離装置14の汚泥出口と配管36とは、汚泥返送配管44により接続されている。配管36には、モリブデン化合物供給配管26が接続されている。配管40と脱窒装置12とは、硝化液返送配管46により接続されている。   An example of such a water treatment apparatus is shown in FIG. In the water treatment apparatus 5 of FIG. 3, the pipe 36 is connected to the inlet of the denitrification apparatus 12, the outlet of the denitrification apparatus 12 and the inlet of the nitrification apparatus 10 are connected by the pipe 38, and the outlet of the nitrification apparatus 10 And the inlet of the solid-liquid separator 14 are connected by a pipe 40, the pipe 42 is connected to the treated water outlet of the solid-liquid separator 14, the sludge outlet of the solid-liquid separator 14 and the pipe 36 are sludge It is connected by the return pipe 44. A molybdenum compound supply pipe 26 is connected to the pipe 36. The pipe 40 and the denitrifying device 12 are connected by a nitrification liquid return pipe 46.

水処理装置5において、アンモニア態窒素および有機態窒素を含む被処理水は、配管36を通して、脱窒装置12へ送液される。一方、後段の硝化装置10から硝化液の少なくとも一部が硝化液返送配管46を通して脱窒装置12へ送液される。ここで、配管36において、被処理水に対して、モリブデン化合物供給配管26を通してモリブデン化合物が供給され、モリブデン濃度が0.025mgMo/gN以上となるようにモリブデン化合物を存在させる(モリブデン化合物供給工程)。   In the water treatment apparatus 5, the water to be treated containing ammonia nitrogen and organic nitrogen is sent to the denitrification apparatus 12 through the pipe 36. On the other hand, at least a part of the nitrification liquid is sent to the denitrification device 12 through the nitrification liquid return pipe 46 from the nitrification device 10 in the latter stage. Here, in the pipe 36, the molybdenum compound is supplied to the water to be treated through the molybdenum compound supply pipe 26, and the molybdenum compound is made to have a molybdenum concentration of 0.025 mg Mo / gN or more (molybdenum compound supply step) .

硝化装置10において、微生物活性汚泥中に含まれる独立栄養性のアンモニア酸化菌と亜硝酸酸化菌とを含む硝化菌により、被処理水に含まれるアンモニア態窒素が亜硝酸または硝酸態窒素にまで酸化される(硝化工程)。脱窒装置12において、微生物活性汚泥中に含まれる従属栄養性の脱窒菌により、硝化装置10(硝化工程)で生成した亜硝酸または硝酸態窒素が窒素ガスにまで還元される(脱窒工程)。脱窒液は、配管38を通して、硝化装置10へ送液され、硝化液の少なくとも一部は、配管40を通して、固液分離装置14へ送液される。以降、図1の水処理装置1と同様にして処理が行われる。   In the nitrification apparatus 10, ammonia nitrogen contained in the water to be treated is oxidized to nitrite or nitrate nitrogen by nitrification bacteria including autotrophic ammonia oxidizing bacteria and nitrite oxidizing bacteria contained in the microorganism activated sludge (Nitrification process). In denitrification apparatus 12, nitrous acid or nitrate nitrogen generated in nitrification apparatus 10 (nitrification process) is reduced to nitrogen gas by heterotrophic denitrification bacteria contained in microbial activated sludge (denitrification process) . The denitrifying solution is sent to the nitrification apparatus 10 through the pipe 38, and at least a part of the nitrification solution is sent to the solid-liquid separator 14 through the pipe 40. Thereafter, the process is performed in the same manner as the water treatment apparatus 1 of FIG.

処理水の窒素濃度をさらに低減させる場合には、図3の水処理装置5における硝化装置10と固液分離装置14との間に、後脱窒手段として後脱窒装置と、酸化手段として酸化装置とをさらに備えてもよい。   In order to further reduce the nitrogen concentration of the treated water, the post denitrification device as the post denitrification means and the oxidation as the oxidation means are provided between the nitrification device 10 and the solid-liquid separation device 14 in the water treatment device 5 of FIG. And the apparatus.

このような形態の水処理装置の例を図4に示す。図4の水処理装置7は、後脱窒手段として後脱窒装置48と、酸化手段として酸化装置30とさらに備える。硝化装置10の出口と後脱窒装置48の入口とは、配管50により接続され、後脱窒装置48の出口と酸化装置30の入口とは、配管52により接続され、酸化装置30の出口と固液分離装置14の入口とは、配管54により接続されている。後脱窒装置48には、水素供与体供給配管28が接続されている。配管50と脱窒装置12とは、硝化液返送配管46により接続されている。   An example of such a water treatment apparatus is shown in FIG. The water treatment device 7 of FIG. 4 further includes a post denitrification device 48 as a post denitrification means, and an oxidizer 30 as an oxidation means. The outlet of the nitrification apparatus 10 and the inlet of the post denitrification apparatus 48 are connected by a pipe 50, the outlet of the post denitrification apparatus 48 and the inlet of the oxidizer 30 are connected by a pipe 52, and the outlet of the oxidizer 30 and The inlet of the solid-liquid separator 14 is connected by a pipe 54. A hydrogen donor supply pipe 28 is connected to the post denitrification device 48. The pipe 50 and the denitrifying device 12 are connected by a nitrification liquid return pipe 46.

水処理装置7において、アンモニア態窒素および有機態窒素を含む被処理水は、配管36を通して、脱窒装置12へ送液される。一方、後段の硝化装置10から硝化液の少なくとも一部が硝化液返送配管46を通して脱窒装置12へ送液される。ここで、配管36において、被処理水に対して、モリブデン化合物供給配管26を通してモリブデン化合物が供給され、モリブデン濃度が0.025mgMo/gN以上となるようにモリブデン化合物を存在させる(モリブデン化合物供給工程)。   In the water treatment device 7, the water to be treated containing ammonia nitrogen and organic nitrogen is sent to the denitrification device 12 through the pipe 36. On the other hand, at least a part of the nitrification liquid is sent to the denitrification device 12 through the nitrification liquid return pipe 46 from the nitrification device 10 in the latter stage. Here, in the pipe 36, the molybdenum compound is supplied to the water to be treated through the molybdenum compound supply pipe 26, and the molybdenum compound is made to have a molybdenum concentration of 0.025 mg Mo / gN or more (molybdenum compound supply step) .

硝化装置10において、微生物活性汚泥中に含まれる独立栄養性のアンモニア酸化菌と亜硝酸酸化菌とを含む硝化菌により、被処理水に含まれるアンモニア態窒素が亜硝酸または硝酸態窒素にまで酸化される(硝化工程)。脱窒装置12において、微生物活性汚泥中に含まれる従属栄養性の脱窒菌により、硝化装置10(硝化工程)で生成した亜硝酸または硝酸態窒素が窒素ガスにまで還元される(脱窒工程)。脱窒液は、配管38を通して、硝化装置10へ送液され、硝化液の少なくとも一部は、配管50を通して、後脱窒装置48へ送液され、後脱窒装置48において、脱窒菌により、硝化装置10(硝化工程)で生成した亜硝酸または硝酸態窒素が窒素ガスにまで還元される(脱窒工程)。脱窒液は、配管52を通して、酸化装置30へ送液される。以降、図2の水処理装置3と同様にして処理が行われる。硝化液の少なくとも一部は、硝化液返送配管46を通して、脱窒装置12へ送液される。   In the nitrification apparatus 10, ammonia nitrogen contained in the water to be treated is oxidized to nitrite or nitrate nitrogen by nitrification bacteria including autotrophic ammonia oxidizing bacteria and nitrite oxidizing bacteria contained in the microorganism activated sludge (Nitrification process). In denitrification apparatus 12, nitrous acid or nitrate nitrogen generated in nitrification apparatus 10 (nitrification process) is reduced to nitrogen gas by heterotrophic denitrification bacteria contained in microbial activated sludge (denitrification process) . The denitrifying solution is sent to the nitrifying apparatus 10 through the pipe 38, and at least a part of the nitrification solution is sent to the post denitrifying apparatus 48 through the pipe 50, and in the post denitrifying apparatus 48, by the denitrifying bacteria. Nitrite or nitrate nitrogen produced in the nitrification apparatus 10 (nitrification process) is reduced to nitrogen gas (denitrification process). The denitrifying solution is sent to the oxidizer 30 through the pipe 52. Thereafter, the treatment is performed in the same manner as the water treatment device 3 of FIG. At least a portion of the nitrification liquid is sent to the denitrification device 12 through the nitrification liquid return pipe 46.

脱窒工程において、処理水の水理学的滞留時間における水素供与体の最大濃度と最小濃度との差が、50mgTOC/L以上となるように、水素供与体の添加量に時間変動を与え、硝化菌と脱窒菌とを含む微生物活性汚泥をグラニュール化させることが好ましい。脱窒反応において添加を行う水素供与体の濃度に変動を与えることにより、脱窒菌が自己造粒したグラニュールが容易に形成可能である。   In the denitrification step, the amount of hydrogen donor added is temporally varied so that the difference between the maximum concentration and the minimum concentration of hydrogen donor in the hydraulic retention time of treated water is 50 mg TOC / L or more, and nitrification It is preferable to granulate microbial activated sludge containing bacteria and denitrifying bacteria. By varying the concentration of the hydrogen donor to be added in the denitrification reaction, it is possible to easily form self-granulated granules of denitrifying bacteria.

さらに、このグラニュールを硝化、脱窒を行う窒素含有水の処理システム内で循環させることにより、硝化菌等のすべての菌群をグラニュール化し、窒素含有被処理水の処理装置全体を実質的に同一のグラニュールで処理することが可能である。   Furthermore, by circulating this granule in the treatment system for nitrogen-containing water that carries out nitrification and denitrification, all the bacteria groups such as nitrifying bacteria are granulated, and the entire treatment apparatus for nitrogen-containing treated water is substantially used. It is possible to process with the same granule.

また、脱窒工程における水素供与体の最大濃度と最小濃度との差を大きくし、微生物活性汚泥のグラニュール化を効率的に進行させる場合には、脱窒工程は、少なくとも第一脱窒工程と第二脱窒工程とを含む2つ以上の工程としてもよい。脱窒工程は、少なくとも第一脱窒工程と第二脱窒工程とを含み、脱窒工程において、第二脱窒工程における処理水の水理学的滞留時間における第一脱窒工程における水素供与体の最大濃度と第二脱窒工程における水素供与体の最小濃度との差が、50mgTOC/L以上となるように、少なくとも第一脱窒工程において水素供与体を供給してもよい。   In the case where the difference between the maximum concentration and the minimum concentration of hydrogen donors in the denitrification step is increased and the granulation of the microorganism activated sludge is efficiently advanced, the denitrification step comprises at least the first denitrification step And two or more steps including the second denitrification step. The denitrification step includes at least a first denitrification step and a second denitrification step, and in the denitrification step, the hydrogen donor in the first denitrification step in the hydraulic retention time of the treated water in the second denitrification step The hydrogen donor may be supplied at least in the first denitrification step such that the difference between the maximum concentration of hydrogen and the minimum concentration of hydrogen donor in the second denitrification step is 50 mg TOC / L or more.

このような形態の水処理装置の例を図5に示す。図5の水処理装置9は、脱窒手段として、第1脱窒装置58と第2脱窒装置60とを備える。硝化装置10の出口と第1脱窒装置58の入口とは、配管62により接続され、第1脱窒装置58の出口と第2脱窒装置60の入口とは、配管64により接続され、第2脱窒装置60の出口と酸化装置30の入口とは、配管66により接続されている。   An example of such a water treatment apparatus is shown in FIG. The water treatment device 9 of FIG. 5 includes a first denitrification device 58 and a second denitrification device 60 as denitrification means. The outlet of the nitrification apparatus 10 and the inlet of the first denitrification apparatus 58 are connected by a pipe 62, and the outlet of the first denitrification apparatus 58 and the inlet of the second denitrification apparatus 60 are connected by a pipe 64. The outlet of the denitrifying device 60 and the inlet of the oxidizing device 30 are connected by a pipe 66.

硝化装置10で得られた硝化液は、配管62を通して第1脱窒装置58へ送液される。第1脱窒装置58において、水素供与体供給配管28を通して水素供与体が供給され、微生物活性汚泥中に含まれる従属栄養性の脱窒菌と接触された後、混合液は、配管64を通して第2脱窒装置60へ送液され、第2脱窒装置60において、脱窒菌により、硝化装置10(硝化工程)で生成した亜硝酸または硝酸態窒素が窒素ガスにまで還元される(脱窒工程)。脱窒液は、配管66を通して、酸化装置30へ送液される。以降、図2の水処理装置3と同様にして処理が行われる。   The nitrifying solution obtained by the nitrifying device 10 is sent to the first denitrifying device 58 through the pipe 62. After the hydrogen donor is supplied through the hydrogen donor supply pipe 28 in the first denitrification apparatus 58 and brought into contact with the heterotrophic denitrifying bacteria contained in the microorganism-activated sludge, the mixed solution is subjected to the second The liquid is sent to the denitrifying device 60, and the nitrous acid or nitrate nitrogen generated in the nitrifying device 10 (nitrification step) is reduced to nitrogen gas by the denitrifying bacteria in the second denitrifying device 60 (denitrification step) . The denitrifying solution is sent to the oxidizer 30 through the pipe 66. Thereafter, the treatment is performed in the same manner as the water treatment device 3 of FIG.

以下、実施例および比較例を挙げ、本発明をより具体的に詳細に説明するが、本発明は、以下の実施例に限定されるものではない。   Hereinafter, the present invention will be described in more detail by way of examples and comparative examples, but the present invention is not limited to the following examples.

以下に連続通水試験機を用いた実施例および比較例を示す。なお、全て室温を20℃で制御した条件で実施した。   Examples and comparative examples using a continuous water flow tester are shown below. In addition, all were implemented on the conditions which controlled room temperature at 20 degreeC.

<実施例1>
実施例1では、図5に示す水処理装置9の構成のベンチスケール試験機を用いた。硝化菌および脱窒菌をグラニュール化させ、模擬排水の硝化脱窒処理試験を実施した。模擬排水としては、純水にアンモニア態窒素として400mgN/Lとなるように溶解させたものを用い、その他の栄養源としてリン酸および微量元素薬液を添加したものを用いた。本試験に用いた微量元素薬液にはモリブデンは含まないものを用いた。脱窒のための水素供与体はメタノールを用い、第1脱窒槽へ間欠的に添加し、第1脱窒槽内の最大メタノール濃度と、第2脱窒槽内の最小メタノール濃度との差が、50mgTOC/L以上となるようにした。硝化槽、第1脱窒槽、第2脱窒槽にはpHコントローラを設置し、塩酸または水酸化ナトリウムを用いて槽内pHを7〜7.5に調整した。固液分離槽から得られた濃縮汚泥は硝化槽へと返送した。0日目から45日目まではモリブデン添加は実施せず(比較例1)、46日目からモリブデン化合物(モリブデン酸ナトリウム)を被処理水に対して0.1mgMo/Lとなるように添加を開始した(実施例1)。モリブデン添加濃度は、被処理水の窒素濃度に対しては0.25mgMo/gNの条件である。結果を図6,7に示す。図6は、硝化槽容積負荷[kgN/(m・d)]、硝化槽のアンモニア態窒素濃度[mgN/L]の推移を示し、図7は、経過日数[day]に対する脱窒槽容積負荷[kgN/(m・d)]、処理水の総窒素濃度[mgN/L]の推移を示す。
Example 1
In Example 1, a bench scale tester having the configuration of the water treatment apparatus 9 shown in FIG. 5 was used. The nitrifying bacteria and the denitrifying bacteria were granulated, and the nitrification denitrification treatment test of the simulated drainage was carried out. As simulated drainage, what was made to melt | dissolve so that it might be set to 400 mgN / L as ammonia nitrogen in pure water was used, and what added the phosphoric acid and trace element chemical | medical solution was used as another nutrition source. The trace element chemical | medical solution used for this test used what does not contain molybdenum. The hydrogen donor for denitrification uses methanol and is intermittently added to the first denitrification tank, and the difference between the maximum methanol concentration in the first denitrification tank and the minimum methanol concentration in the second denitrification tank is 50 mg TOC It was made to be more than / L. A pH controller was installed in the nitrification tank, the first denitrification tank, and the second denitrification tank, and the pH in the tank was adjusted to 7 to 7.5 using hydrochloric acid or sodium hydroxide. Concentrated sludge obtained from the solid-liquid separation tank was returned to the nitrification tank. Do not add molybdenum from day 0 to 45 (comparative example 1), and add molybdenum compound (sodium molybdate) to be 0.1 mg Mo / L relative to the water to be treated from day 46 It started (Example 1). The concentration of added molybdenum is 0.25 mg Mo / g N for the nitrogen concentration of the water to be treated. The results are shown in FIGS. FIG. 6 shows the transition of the nitrification tank volume load [kgN / (m 3 · d)] and the ammonia nitrogen concentration [mgN / L] of the nitrification tank, and FIG. 7 shows the denitrification tank volume load with respect to the elapsed days [day] [KgN / (m 3 · d)] shows the transition of total nitrogen concentration [mgN / L] of treated water.

初期の比較例1において、硝化槽における容積負荷を0.2kgN/(m・d)で通水開始したが、硝化槽においてアンモニア態窒素が5〜60mgN/L残存し、負荷を上昇させることができず、硝化速度は0.15〜0.25kgN/(m・d)で停滞した。硝化速度の停滞に伴い、脱窒速度も0.3〜0.5kgN/(m・d)で停滞した。比較例1の期間中、安定運転が可能となる汚泥当りの処理速度は、硝化で0.05kgN/(kgVSS・d)であった。 In Comparative Example 1 in the initial stage, water flow was started with a volumetric load of 0.2 kg N / (m 3 · d) in the nitrification tank, but 5 to 60 mg N / L of ammonia nitrogen remains in the nitrification tank to increase the load. The nitrification rate stagnated at 0.15 to 0.25 kgN / (m 3 · d). With the stagnation of the nitrification rate, the denitrification rate also stagnated at 0.3 to 0.5 kgN / (m 3 · d). During the period of Comparative Example 1, the treatment rate per sludge which enables stable operation was 0.05 kgN / (kgVSS · d) in nitrification.

次に、被処理水へのモリブデン添加を開始したところ、処理速度の上昇が認められ、最大で1.1kgN/(m・d)の硝化速度を確認できた。なお、実施例1の期間中は硝化槽のアンモニア態窒素は常に1mgN/L以下で推移した。硝化速度の上昇に伴い、脱窒速度の上昇も認められ、最大で2.2kgN/(m・d)に達した。比較例1の期間中、汚泥活性を示す汚泥当りの処理速度は、硝化で0.24kgN/(kgVSS・d)、脱窒で0.54kgN/(kgVSS・d)での安定運転を確認できた。 Next, when addition of molybdenum to the water to be treated was started, an increase in the treatment rate was observed, and a nitrification rate of 1.1 kgN / (m 3 · d) at maximum could be confirmed. During the period of Example 1, ammonia nitrogen in the nitrification tank remained at 1 mg N / L or less at all times. With the increase of the nitrification rate, the denitrification rate was also increased, reaching up to 2.2 kgN / (m 3 · d). During the period of Comparative Example 1, the treatment speed per sludge showing sludge activity was 0.24 kgN / (kgVSS · d) for nitrification and 0.54 kgN / (kgVSS · d) for denitrification. .

<比較例2>
比較例2では、図5に示す水処理装置9の構成のベンチスケール試験機を用い、連続通水試験を行った。模擬排水としては、純水中にアンモニア態窒素として800mgN/Lとなるように調整し、その他リン酸および微量元素薬液(モリブデンを含まない)を添加したものを用いた。微量元素の補給を目的として120日目から215日目まではモリブデンを含まない井水(モリブデン濃度:0.0001mgMo/L以下(検出限界以下))を、216日目から280日目まではモリブデンを含む工水を被処理水の10%流量を添加して補給を行った。なお、工水中のモリブデン濃度は0.0006mgMo/Lであった。井水および工水中のモリブデン濃度は、ICP質量分析法(ICP−MS)を用いて測定した。
Comparative Example 2
In the comparative example 2, the continuous water flow test was done using the bench scale tester of the structure of the water treatment apparatus 9 shown in FIG. As simulated drainage, it adjusted to 800 mgN / L as ammonia nitrogen in pure water, and used what added other phosphoric acid and trace element chemical | medical solution (it does not contain molybdenum). Molybdenum-free well water (molybdenum concentration: 0.0001 mg Mo / L or less (below detection limit)) from the 120th day to the 215th day for the purpose of trace element supplementation, molybdenum from the 216th day to the 280th day Water containing 10% was added by adding 10% flow rate of treated water. In addition, the molybdenum concentration in industrial water was 0.0006 mgMo / L. The molybdenum concentration in the well water and the working water was measured using ICP mass spectrometry (ICP-MS).

硝化槽容積負荷[kgN/(m・d)]と硝化槽の残存アンモニア態窒素濃度[mgN/L]の推移を図8、脱窒槽容積負荷[kgN/(m・d)]と処理水の総窒素濃度[mgN/L]の推移を図9に示す。図8から分かるように、硝化槽容積負荷を0.8kgN/(m・d)まで上昇させたが、169日目にはアンモニア態窒素濃度が41mgN/L残存し、171日目には130mgN/Lにまで上昇した。その後も硝化性能は安定せず、10から40mgN/Lが硝化槽内で残存することがあり、安定運転ができなかった。また、試験期間中の硝化活性は0.02〜0.075kgN/(kgVSS・d)であった。硝化の不安定性に伴い、脱窒も処理が安定せず、処理水TNは最大で150mgN/L程度にまで上昇した。 Transition of nitrification tank volume load [kgN / (m 3 · d)] and residual ammonia nitrogen concentration of nitrification tank [mgN / L] Figure 8, denitrification tank volume load [kgN / (m 3 · d)] and treatment The transition of the total nitrogen concentration [mgN / L] of water is shown in FIG. As can be seen from FIG. 8, the nitrification tank volume load was increased to 0.8 kgN / (m 3 · d), but 41 mgN / L of ammoniacal nitrogen concentration remained on day 169 and 130 mg N on day 171. It rose to / L. Even after that, the nitrification performance is not stable, 10 to 40 mg N / L may remain in the nitrification tank, and stable operation could not be performed. In addition, the nitrification activity during the test period was 0.02 to 0.075 kgN / (kgVSS · d). Due to the instability of nitrification, denitrification was not stable, and the treated water TN increased up to about 150 mg N / L.

<実施例2>
比較例2と同様の条件の模擬排水、試験装置を用い、モリブデン化合物溶液の添加影響を連続通水試験で検証した。モリブデン添加濃度としては被処理水のアンモニア態窒素濃度800mgN/Lに対して、0.02mgMo/Lとし、175日目から添加を開始した。モリブデン添加濃度は、被処理水の窒素濃度に対しては0.025mgMo/gNの条件である。
Example 2
The influence of the addition of the molybdenum compound solution was verified by a continuous water flow test using simulated drainage under the same conditions as Comparative Example 2 and a test apparatus. The addition concentration of molybdenum was 0.02 mg Mo / L with respect to the ammonia nitrogen concentration of 800 mg N / L of the water to be treated, and the addition was started from the 175th day. The concentration of added molybdenum is 0.025 mg Mo / g N for the nitrogen concentration of the water to be treated.

硝化槽容積負荷[kgN/(m・d)]と硝化槽の残存アンモニア態窒素濃度[mgN/L]の推移を図10、脱窒槽容積負荷[kgN/(m・d)]と処理水の総窒素濃度[mgN/L]の推移を図11に示す。その結果、モリブデンを添加していない期間は、硝化槽容積負荷を上げられず、175日目に55mgN/Lのアンモニア態窒素が残存した。175日目からMo化合物の添加を開始したところ、アンモニア態窒素濃度の低下が確認され、容積負荷を0.8〜0.9kgN/(m・d)にまで上昇させても安定運転が可能であった。モリブデン添加前の硝化活性は最大で0.05kgN/(kgVSS・d)であったが、モリブデン添加開始後の硝化活性は0.11kgN/(kgVSS・d)まで上昇した。脱窒に関しても、脱窒槽容積負荷として1.4kgN/(m・d)まで上昇した。 Transition of the nitrification tank volume load [kg N / (m 3 · d)] and the residual ammonia nitrogen concentration [mg N / L] of the nitrification tank Figure 10, denitrification tank volume load [kg N / (m 3 · d)] The transition of the total nitrogen concentration [mgN / L] of water is shown in FIG. As a result, during the period when molybdenum was not added, the volumetric load of the nitrification tank could not be increased, and 55 mgN / L of ammonia nitrogen remained on the 175th day. When the addition of Mo compounds was started from the 175th day, a drop in ammonia nitrogen concentration was confirmed, and stable operation was possible even if the volume load was increased to 0.8 to 0.9 kg N / (m 3 · d) Met. Although the nitrification activity before the addition of molybdenum was 0.05 kgN / (kgVss · d) at the maximum, the nitrification activity after the start of the addition of molybdenum increased to 0.11 kgN / (kgVss · d). With regard to denitrification also, the denitrification tank volume load increased to 1.4 kgN / (m 3 · d).

<実施例3>
実施例2と同様の条件の模擬排水、試験装置を用い、モリブデン化合物の添加影響を連続通水試験で検証した。添加濃度としては被処理水アンモニア態窒素濃度が800mgN/Lに対して、0.1mgMo/Lとし、343日目から添加を開始した。モリブデン添加濃度は、被処理水の窒素濃度に対しては0.125mgMo/gNの条件である。
Example 3
The effect of addition of the molybdenum compound was verified by a continuous water flow test using simulated drainage under the same conditions as in Example 2 and a test apparatus. The addition concentration was 0.1 mg Mo / L for the ammonia water nitrogen concentration of 800 mg N / L as the addition concentration, and the addition was started from the 343th day. The concentration of added molybdenum is 0.125 mg Mo / g N for the nitrogen concentration of the water to be treated.

硝化槽容積負荷[kgN/(m・d)]と硝化槽の残存アンモニア態窒素濃度[mgN/L]の推移を図12、脱窒槽容積負荷[kgN/(m・d)]と処理水の総窒素濃度[mgN/L]の推移を図13に示す。その結果、モリブデンを添加していない期間は脱窒槽で70から80mg/L程度の硝酸態窒素が検出されていたため負荷を上げることができず、硝化槽容積負荷として0.25kgN/(m・d)程度で停滞していた。343日目からモリブデン溶液の添加を開始し、負荷の上昇を試みた。346日目に硝化槽でアンモニア態窒素が37mgN/L検出されたが、その後アンモニア態窒素濃度の低下が見られた。硝化槽容積負荷を0.86kgN/(m・d)まで上昇させたが、硝化槽でアンモニア態窒素が検出されることはなく、脱窒槽でも処理水TNは5mgN/L以下で推移した。モリブデン添加前の硝化活性は0.05〜0.06kgN/(kgVSS・d)で停滞していたが、モリブデン添加開始後、活性の向上が見られ、0.2kgN/(kgVSS・d)への上昇が確認された。 Transition of nitrification tank volume load [kgN / (m 3 · d)] and residual ammonia nitrogen concentration of nitrification tank [mgN / L] Figure 12, denitrification tank volume load [kgN / (m 3 · d)] and treatment The transition of the total nitrogen concentration [mgN / L] of water is shown in FIG. As a result, since the nitrate nitrogen of about 70 to 80 mg / L was detected in the denitrification tank during the period where molybdenum was not added, the load could not be increased, and the volumetric load of the nitrification tank was 0.25 kgN / (m 3 · · d) It was stagnating at a grade. The addition of the molybdenum solution was started from day 343 and an increase in load was attempted. On the 346th day, 37 mg N / L of ammonia nitrogen was detected in the nitrification tank, and a decrease in ammonia nitrogen concentration was observed thereafter. Although the nitrification tank volume load was increased to 0.86 kgN / (m 3 · d), no ammonia nitrogen was detected in the nitrification tank, and the treated water TN remained at 5 mgN / L or less even in the denitrification tank. The nitrification activity before addition of molybdenum was stagnated at 0.05 to 0.06 kgN / (kgVss · d), but after the addition of molybdenum, the activity was improved, and the activity to 0.2 kgN / (kgVss · d) was observed. The rise was confirmed.

以上の結果のまとめを図14に示す。図14より、硝化工程において、被処理水に対して、モリブデン濃度が0.025mgMo/gN以上となるようにモリブデン化合物を存在させることが好ましいことがわかる。   A summary of the above results is shown in FIG. It is understood from FIG. 14 that in the nitrification step, it is preferable to allow the molybdenum compound to be present so that the molybdenum concentration is 0.025 mg Mo / gN or more with respect to the water to be treated.

このように、実施例の方法により、アンモニア態窒素および有機態窒素を含む被処理水の生物学的処理において、被処理水中の窒素濃度が高濃度であっても高い処理速度で安定して処理することができた。   Thus, according to the method of the embodiment, in biological treatment of water to be treated containing ammonia nitrogen and organic nitrogen, stable treatment is carried out at a high treatment rate even if the nitrogen concentration in the water to be treated is high. We were able to.

以下、モリブデン化合物の添加濃度がアンモニア酸化反応および脱窒反応へ与える阻害影響を、回分試験により評価を実施した。   Hereinafter, the inhibition effect of the added concentration of the molybdenum compound on the ammonia oxidation reaction and the denitrification reaction was evaluated by a batch test.

[脱窒へのモリブデン添加影響試験(回分試験)]
硝化脱窒汚泥を用いて、モリブデン添加が脱窒反応に与える影響を、模擬排水を用いた回分試験により検証した。実験方法の具体的な方法を下記に記す。
[Molybdenum addition impact test for denitrification (batch test)]
Using nitrification and denitrification sludge, the effect of molybdenum addition on denitrification was verified by a batch test using simulated drainage. The specific method of the experimental method is described below.

1.回分試験に用いる模擬排水としては、井水に硝酸態イオンが60mgN/L、リン酸態リンが1mgP/Lとなるように添加したものを用いた。なお、模擬排水中のモリブデン含有濃度は、0.0001mg/L以下であった。
2.予め水素供与体としてのメタノールで馴養された汚泥を純水で洗浄したものを模擬排水に懸濁させ、5個のビーカに分注した。
3.汚泥と模擬排水の混合液にモリブデン酸ナトリウム溶液を各ビーカに0mgMo/L、1mgMo/L、5mgMo/L、10mgMo/L、20mgMo/Lとなるように添加し、撹拌した。
4.撹拌をしながら、水素供与体としてのメタノールを各ビーカに同量ずつ添加し、硝酸の減少速度を評価した。
1. As simulated drainage used for a batch test, what added 60 mgN / L of nitrate ion and 1 mgP / L of phosphate phosphorus to well water was used. In addition, the molybdenum content density | concentration in simulated drainage was 0.0001 mg / L or less.
2. The sludge previously conditioned with methanol as a hydrogen donor, which had been washed with pure water, was suspended in a simulated drainage and dispensed into five beakers.
3. A sodium molybdate solution was added to each beaker so as to be 0 mg Mo / L, 1 mg Mo / L, 5 mg Mo / L, 10 mg Mo / L, 20 mg Mo / L and stirred in a mixed solution of sludge and simulated drainage.
4. The same amount of methanol as a hydrogen donor was added to each beaker while stirring, and the rate of reduction of nitric acid was evaluated.

脱窒活性試験の結果、硝酸減少速度とビーカ内の汚泥量から算出される脱窒活性は、Moを添加しない系列では0.43gN/gSS/日、Mo濃度が1mgMo/Lとした系列では0.46、5mgMo/Lとした系列では0.45gN/gSS/日、10mgMo/Lとした系列では0.42gN/gSS/日、20mgMo/Lとした系列では0.41gN/gSS/日となり、Moを添加しない系列と比較して僅かではあるが、Mo濃度が1mgMo/Lとした系列で8%、5mgMo/Lとした系列で5%の活性向上が確認された。一方で、Mo濃度を20mgMo/Lと高濃度に添加した系列においても、最も脱窒活性が高かったMo濃度1mgMo/Lの系列と比較して約10%の活性低下しか確認されず、脱窒へのMoの顕著な阻害は確認されなかった。   As a result of the denitrification activity test, the denitrification activity calculated from the rate of nitrate reduction and the amount of sludge in the beaker is 0.43 gN / g SS / day for the series without adding Mo, and 0 for the series with Mo concentration of 1 mg Mo / L. For a series with .46, 5 mg Mo / L, 0.45 g N / g SS / day, for a series with 10 mg Mo / L 0.42 g N / g SS / day, for a series with 20 mg Mo / L, 0.41 g N / g SS / day, Mo Although there was a slight increase as compared with the series where no Mo was added, an activity improvement of 5% was confirmed in the series where Mo concentration was 1 mg Mo / L and 8% and 5 mg Mo / L. On the other hand, even in the series where Mo concentration was added as high as 20 mg Mo / L, only about 10% decrease in activity was confirmed compared to the series with Mo concentration 1 mg Mo / L that had the highest denitrification activity. No significant inhibition of Mo was observed.

[アンモニア酸化へのMo添加影響試験(回分試験)]
硝化脱窒汚泥を用いて、モリブデン添加がアンモニア酸化反応に与える影響を、模擬排水を用いた回分試験により検証した。実験方法の具体的な方法を下記に記す。
[Mo addition test for ammonia oxidation (batch test)]
Using nitrification and denitrification sludge, the effect of molybdenum addition on ammonia oxidation reaction was verified by a batch test using simulated drainage. The specific method of the experimental method is described below.

1.回分試験に用いる模擬排水としては、井水にアンモニア態イオンが60mgN/L、リン酸態リンが1mgP/Lとなるように添加したものを用いた。なお、模擬排水中のモリブデン含有濃度は、0.0001mg/L以下であった。
2.供試汚泥を純水で洗浄したものを模擬排水に懸濁させ、5個のビーカに分注した。
3.汚泥と模擬排水の混合液にモリブデン酸ナトリウム溶液を各ビーカに0mgMo/L、0.1mgMo/L、0.5mgMo/L、2mgMo/L、10mgMo/Lとなるように添加し、それぞれ曝気を開始した。
4.それぞれのアンモニア態窒素濃度の減少速度を評価した。
1. As simulated drainage used for a batch test, what added ammonia water 60 mgN / L and phosphate phosphate 1 mg / well to well water was used. In addition, the molybdenum content density | concentration in simulated drainage was 0.0001 mg / L or less.
2. The sample sludge washed with pure water was suspended in simulated drainage and dispensed into five beakers.
3. Add sodium molybdate solution to each beaker so that it becomes 0mgMo / L, 0.1mgMo / L, 0.5mgMo / L, 2mgMo / L, 10mgMo / L, and start aeration respectively did.
4. The rate of decrease of each ammoniacal nitrogen concentration was evaluated.

アンモニア酸化活性試験の結果、アンモニア減少速度とビーカ内の汚泥量から算出されるアンモニア酸化活性は、Moを添加しない系列では0.18gN/gSS/日、Mo濃度が0.1mgMo/Lとした系列では0.13gN/gSS/日、0.5mgMo/Lとした系列では0.13gN/gSS/日、2mgMo/Lとした系列では0.13gN/gSS/日、10mgMo/Lとした系列では0.10gN/gSS/日となり、Moを添加しなかった系列のアンモニア酸化活性が最も高く、10mgMo/Lとした系列のアンモニア酸化活性が最も低い結果となった。本回分試験結果より、アンモニア酸化反応へのモリブデン濃度の阻害性を抑制するためには、2mgMo/L以下とすることが好ましいと考えられた。   As a result of the ammonia oxidation activity test, the ammonia oxidation activity calculated from the ammonia reduction rate and the amount of sludge in the beaker was 0.18 gN / g SS / day in the series without adding Mo, and the series in which the Mo concentration was 0.1 mgMo / L. In the series, 0.13 gN / g SS / day, 0.5 mgMo / L, 0.13 g N / g SS / day, 2 mg Mo / L, 0.13 g N / g SS / day, 10 mg Mo / L. It became 10 gN / g SS / day, and the ammonia oxidation activity of the series which did not add Mo became the highest, and the result of ammonia oxidation activity of the series made 10 mg Mo / L became the lowest. From this batch test result, in order to suppress the inhibitory property of the molybdenum concentration to ammonia oxidation reaction, it was thought that it is preferable to set it as 2 mgMo / L or less.

1,3,5,7,9 水処理装置、10 硝化装置、12 脱窒装置、14 固液分離装置、16,18,20,22,32,34,36,38,40,42,50,52,54,62,64,66 配管、24,44 汚泥返送配管、26 モリブデン化合物供給配管、28 水素供与体供給配管、30 酸化装置、46 硝化液返送配管、48 後脱窒装置、58 第1脱窒装置、60 第2脱窒装置。   1, 3, 5, 7, 9 water treatment system, 10 nitrification system, 12 denitrification system, 14 solid-liquid separation system, 16, 18, 20, 22, 32, 34, 36, 38, 40, 42, 50, 52, 54, 62, 64, 66 piping, 24, 44 sludge return piping, 26 molybdenum compound supply piping, 28 hydrogen donor supply piping, 30 oxidizer, 46 nitrification liquid return piping, 48 post denitrification, 58 first Denitrification device, 60 Second denitrification device.

Claims (6)

アンモニア態窒素および有機態窒素を含む被処理水を、生物学的に処理する水処理方法であって、
微生物活性汚泥中に含まれる独立栄養性のアンモニア酸化菌と亜硝酸酸化菌とを含む硝化菌により、前記アンモニア態窒素を亜硝酸または硝酸態窒素にまで酸化する硝化工程を含み、
前記硝化工程において、前記被処理水に対して、モリブデン濃度が0.025mgMo/gN以上となるようにモリブデン化合物を存在させ、
汚泥あたりの硝化速度が、0.11[kgN/(kgVSS・日)]以上であることを特徴とする水処理方法。
A water treatment method for biologically treating a water to be treated containing ammonia nitrogen and organic nitrogen,
Including a nitrification step of oxidizing the ammonia nitrogen to nitrite or nitrate nitrogen by nitrifying bacteria including autotrophic ammonia oxidizing bacteria and nitrite oxidizing bacteria contained in the microorganism activated sludge,
In the nitrification step, a molybdenum compound is present such that the concentration of molybdenum in the water to be treated is 0.025 mg Mo / gN or more,
A water treatment method characterized in that the nitrification rate per sludge is 0.11 [kgN / (kgVSS · day)] or more.
請求項1に記載の水処理方法であって、
前記硝化工程におけるモリブデン濃度を、前記被処理水に対して2mgMo/L以下とすることを特徴とする水処理方法。
The water treatment method according to claim 1, wherein
The molybdenum concentration in the said nitrification process shall be 2 mgMo / L or less with respect to the said to-be-processed water, The water treatment method characterized by the above-mentioned.
請求項1または2に記載の水処理方法であって、
前記被処理水中の窒素濃度が、100mgN/L以上であることを特徴とする水処理方法。
The water treatment method according to claim 1 or 2, wherein
The nitrogen concentration in the said to-be-treated water is 100 mgN / L or more, The water treatment method characterized by the above-mentioned.
請求項1〜3のいずれか1項に記載の水処理方法であって、
前記微生物活性汚泥中に含まれる脱窒菌により、前記硝化工程で生成した亜硝酸または硝酸態窒素を窒素ガスにまで還元する脱窒工程をさらに含むことを特徴とする水処理方法。
The water treatment method according to any one of claims 1 to 3, wherein
The water treatment method further includes a denitrification step of reducing nitrous acid or nitrate nitrogen generated in the nitrification step to nitrogen gas by denitrifying bacteria contained in the microorganism-activated sludge.
請求項4に記載の水処理方法であって、
前記脱窒工程において、処理水の水理学的滞留時間における水素供与体の最大濃度と最小濃度との差が、50mgTOC/L以上となるように、前記水素供与体の添加量に時間変動を与えることによって、前記硝化菌と脱窒菌とを含む微生物活性汚泥をグラニュール化させることを特徴とする水処理方法。
The water treatment method according to claim 4, wherein
In the denitrification step, the added amount of the hydrogen donor is temporally varied so that the difference between the maximum concentration and the minimum concentration of the hydrogen donor in the hydraulic retention time of the treated water is 50 mg TOC / L or more. The method according to claim 1, wherein the activated sludge containing the nitrifying bacteria and the denitrifying bacteria is granulated.
請求項5に記載の水処理方法であって、
前記脱窒工程は、少なくとも第一脱窒工程と第二脱窒工程とを含み、
前記脱窒工程において、前記第二脱窒工程における処理水の水理学的滞留時間における前記第一脱窒工程における水素供与体の最大濃度と前記第二脱窒工程における水素供与体の最小濃度との差が、50mgTOC/L以上となるように、少なくとも前記第一脱窒工程において水素供与体を供給することを特徴とする水処理方法。
The water treatment method according to claim 5, wherein
The denitrification step includes at least a first denitrification step and a second denitrification step,
In the denitrification step, the maximum concentration of hydrogen donors in the first denitrification step and the minimum concentration of hydrogen donors in the second denitrification step at the hydraulic retention time of the treated water in the second denitrification step A hydrogen donor is supplied at least in the first denitrification step such that the difference between the two is 50 mg TOC / L or more.
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