JP4390889B2

JP4390889B2 - Method and apparatus for decomposing volatile organic compounds

Info

Publication number: JP4390889B2
Application number: JP02523499A
Authority: JP
Inventors: 茂樹山下; 政美北川
Original assignee: Ebara Corp
Current assignee: Ebara Corp
Priority date: 1999-02-02
Filing date: 1999-02-02
Publication date: 2009-12-24
Anticipated expiration: 2019-02-02
Also published as: JP2000225314A

Description

【０００１】
【発明の属する技術分野】
本発明は、揮発性有機化合物の分解方法及び処理装置に関し、特に、塗装工場、鋳造工場、印刷工場及びフィルム製造工場などから排出されるトルエン、ベンゼン、キシレン、スチレン、メタノール及び酢酸エチル等の揮発性有機化合物を含有する排ガス及び下水又は排水処理場などの廃ガスを処理する技術である。
【０００２】
【従来の技術】
揮発性有機化合物の生物処理はランニングコストが低く、安全性の高い方法である。
生物処理法では、処理対象の揮発性有機化合物（なお、本明細書中では、ＶＯＣともいう）を分解する微生物が必要とされる。そこで、従来は微生物の接種源として活性汚泥などを添加し、馴致によって、処理対象物質の分解に適した生物を増殖させた。従って、馴致期間中はＶＯＣが十分分解されなかった。馴致期間は物質によって異なるが、トルエンの場合、３週間程度を必要とした。
また、工場の操業は通常、必ずしも連続的でない。夜間、週末及びその他の休日や点検のために停止される可能性がある。生物処理装置にはその間ＶＯＣが流入しないため、生物量が減少し、再びＶＯＣが流入したときに始動時には十分な除去性能が得られない事態が予測される。特に数日以上に渡る長期の運転停止は生物活性を低下させ、十分な分解性能を回復するまでに、運転開始時と同様の期間を必要とする場合もある。
【０００３】
【発明が解決しようとする課題】
本発明は、上記従来の技術の欠点を克服し、生物処理装置の処理能力を短時間で高め、その結果、運転開始時の馴致期間を短縮し、処理性能が低下したときに短時間で処理性能を回復できる揮発性有機化合物の分解方法および処理装置を提供することを目的とする。
【０００４】
【課題を解決するための手段】
上記の目的は、以下の手段で達成された。
（１）処理の対象となる揮発性有機化合物を主要な炭素源とする液体培地に土壌または活性汚泥と微生物を保持させる樹脂の担体を添加して培養し、培養終了後の該担体を取り出して新たに該担体を接種源として該揮発性有機化合物を主要な炭素源とする液体培地中で再度集積培養する操作を数回繰り返し、選択的に該担体に付着性が高く、該揮発性有機化合物を分解する微生物を増殖させて得られた樹脂の担体を充填層に充填した生物処理装置を設け、該充填層に散水して湿潤状態に維持させながら揮発性有機化合物を通過させることを特徴とする揮発性有機化合物の分解方法。
（２）処理の対象となる揮発性有機化合物を主要な炭素源とする液体培地に土壌または活性汚泥と微生物を保持させる樹脂の担体を添加して培養し、培養終了後の該担体を取り出して新たに該担体を接種源として該揮発性有機化合物を主要な炭素源とする液体培地中で再度集積培養する操作を数回繰り返して、該担体に選択集積培養した微生物を該担体から分離し、その分離した微生物を充填層を備えた生物処理装置に供給することにより、該充填層に微生物を保持させ、該充填層に散水して湿潤状態に維持させながら揮発性有機化合物を通過させることを特徴とする揮発性有機化合物の分解方法。
【０００５】
（３）前記微生物が、アシネトバクター・ゲノスピーシズ１０Ｔｏｌ−５（ＦＥＲＭＰ−１７１８８）もしくはロドコッカス・エリスロポリスＴｏｌ−３（ＦＥＲＭ−１７１８７）であることを特徴とする前記（１）又は（２）記載の揮発性有機化合物の分解方法。
（４）処理の対象となる揮発性有機化合物を主要な炭素源とする液体培地に土壌または活性汚泥と微生物を保持させる樹脂の担体を添加して培養し、培養終了後の該担体を取り出して新たに該担体を接種源として該揮発性有機化合物を主要な炭素源とする液体培地中で再度集積培養する操作を数回繰り返し、選択的に該担体に付着性が高く、該有機化合物を分解する微生物を増殖させて得られた樹脂の担体を充填した充填層、該充填層を湿潤状態に維持させるために散水する散水装置、及び揮発性有機化合物を含有する排ガスを通過させる入口及び出口を備えた生物処理装置を設けたことを特徴とする揮発有機化合物を含有する排ガスの処理装置。
（５）処理の対象となる揮発性有機化合物を主要な炭素源とする液体培地に土壌または活性汚泥と微生物を保持させる樹脂の担体を添加して培養し、培養終了後の該担体を取り出して新たに該担体を接種源として該揮発性有機化合物を主要な炭素源とする液体培地中で再度集積培養する操作を数回繰り返して、該担体に選択集積培養した微生物を、充填層に供給することにより、短時間で除去率を向上させる微生物をもつ充填層、該充填層を湿潤状態に維持させるために散水する散水装置、及び揮発性有機化合物を含有する排ガスを通過させる入口及び出口を備えた生物処理装置を設けたことを特徴とする揮発性有機化合物を含有する排ガスの処理装置。
（６）前記微生物が、アシネトバクター・ゲノスピーシズ１０Ｔｏｌ−５（ＦＥＲＭＰ−１７１８８）もしくはロドコッカス・エリスロポリスＴｏｌ−３（ＦＥＲＭ−１７１８７）であることを特徴とする前記（４）又は（５）記載の揮発性有機化合物を含有する排ガスの処理装置。
【０００６】
前述の従来の技術の様な処理能力の低下は、各排ガス中の処理対象成分を分解する能力を有する微生物の菌体量の絶対的な不足が原因である。従って、装置内に処理対象成分の分解微生物を供給することにより短期間で所定の除去性能が得られる可能性がある。
ＶＯＣ分解微生物は、土壌及び活性汚泥などの混合微生物を微生物接種源として、処理対象ＶＯＣ成分を炭素源とする液体培地中で集積培養することによって得られる。ただし、生物処理装置では特定の担体（以下、充填材ともいう）に付着した微生物が対象成分を分解するため、担体に対する付着能力の無い微生物では充填層内に留まることができず、高い処理性能が期待できない。また、ＶＯＣ分解能力の高い微生物は装置の処理性能を改善できる可能性が高い。従って、生物処理装置に添加する微生物には、担体に対する付着能力と高いＶＯＣ分解性能が求められる。そこで、本発明では、これらの性質を併せ持つ微生物を選択的に大量培養して、生物処理装置に添加したものである。具体的には活性汚泥などの多様な微生物群の中からなんらかの方法でこれらの性質を併せ持つ微生物を効率的に培養するか、又はこれらの性質を有することが明らかにされた純粋分離された微生物、又は微生物混合物を培養し、添加したものである。
【０００７】
なお、上記の（１）〜（６）の方法にあって、微生物を保持する担体は、ポリウレタン、ポリプロピレン、ポリ塩化ビニリデン、アクリルなどの樹脂が考えられる。これらは通気性が高いため、担体として有用である反面、微生物の付着性が低いために装置の性能が上がらないという問題があった。そこで、これらの樹脂に対して付着性の高い微生物を効率的に利用する技術を開発した。生物処理装置の充填層への微生物の添加時点は、生物処理装置の運転開始時または前記生物処理装置の能力が低下した時がよい。生物処理装置の運転開始時または前記生物処理装置の能力が低下した時に生物処理装置の充填層へ微生物を添加するにあたり、添加する微生物としては次のようなものを用いるとよい。すなわち、特定の担体と共に揮発性有機化合物を主要な炭素源とする液体培地に添加して培養し、培養終了後の担体を接種源として揮発性有機化合物を主要な炭素源とする液体培地中で再度集積培養する操作を数回繰り返して選択集積培養したものを添加する。
【０００８】
【発明の実施の形態】
以下、発明の実施の形態を説明する。
図１は、本発明を実施するのに適した実験装置のフロー図である。
微生物菌体の付着した担体１を実験装置に充填し、トルエン含有排ガスを通気する。トルエンガスは例えば市販の液体トルエン薬品２に窒素ガス３をばっ気して発生させる。このガスをコンプレッサー４で発生させた空気で希釈し、充填層５を通過させる。循環水貯槽６には培養液７を注入し、ポンプ８で汲み上げて、連続または間欠的に充填層上部から散水し、微生物に栄養塩及び水分を供給する。培養液７には水道水に尿素、りん酸水素二ナトリウム、硫酸第一鉄などを添加したものを用いる。
【０００９】
担体１に付着させる微生物は、担体に選択的な付着能力があり、かつ揮発性有機化合物を分解できるものであれば特に限定されないが、アシネートバクター・ゲノスピーシス１０Ｔｏｌ−５（ＦＥＲＭＰ−１７１８８）もしくはロドコッカス・エリスロポリスＴｏｌ−３（ＦＥＲＭＰ−１７１８７）がよい。
発明者は処理対象物質を主な炭素源とする液体培地に活性汚泥や土壌などの微生物接種源を添加し、同時に担体１を添加して培養した。培養終了後、この担体１を取り出し、微生物の付着した担体１を接種源として同組成の培地に再度培養した。この操作を数回繰り返した結果、培養後の液体中に微生物菌体による懸濁はほとんど見られなくなり、トルエン分解微生物は担体１に付着して増殖した。また、培養フラスコ中のトルエンの減少速度が次第に速まり、トルエン分解能力の高い微生物が集積していることが示唆された。そこで、菌体が付着した担体１を実験装置に充填し、トルエンを含む排ガスを連続通気して、実験開始当初の処理性能の変化を追跡した。その結果、実験開始２日後には高い除去性能が得られたことから、上記の方法によって担体１に対する付着能力があり、トルエン除去能力の高い微生物を使用することで、短期間で馴致可能であることが分かった。
【００１０】
また、微生物を担持させる担体１の充填層に活性汚泥及び土壌などの微生物接種源を添加し、充填層には栄養塩類を溶解した培養液を連続又は間欠的に散水しながら、排ガスを模擬的に作成したガスを通気した。そして、約２ヶ月後高い除去性能を発揮している装置から担体１を取り出し、付着していた微生物を剥離し、回収した。この微生物相は上記の性質を持っている。
さらにこの微生物を処理対象物質を主な炭素源とする平板培地に塗抹培養して、出現したコロニーから３種類の菌株を単離し、それぞれ名称を、Tol-1 、Tol-3株及びTol-5 株とした。
【００１１】
各微生物の菌体乾燥重量あたりのトルエン分解能力を密閉バイアルを用いた回分実験により測定したところ、Tol-1 株は２．２mg-トルエン/g-菌体/min、Tol-3 株は２．０mg-トルエン/g-菌体/min、Tol-5 株は７．４mg-トルエン/g-菌体/minを示した。一方、連続的にトルエンを分解していた生物処理装置の充填材から剥離させた汚泥は０．６mg- トルエン/g-菌体/minを示した。従って、純粋分離された微生物は何れも高いトルエン分解能力を有することが分かった。
また、Tol-5 株を２g/リットルエタノールを主な炭素源とする液体培地中で充填材を共存させて培養（２５℃、ロータリー振とう）すると、充填材１ｇあたり最大１４０mgの菌体が付着した。
【００１２】
そこで菌体を付着させた充填材を実験装置に充填し、実験を開始し、当初の処理性能を追跡調査したところ、２日後には高い除去性能が得られたことから、Tol-5 株を使用することで短時間で馴致可能であることが分かった。
さらに、Tol-5 株はトルエンの他に、少なくともｍ−キシレン、ｐ−キシレン、スチレン、ベンゼン、ジエチルエーテル、酢酸エチル及びエタノールを分解できることが分かった。従って、これらの物質を処理する際にも、運転開始時にこの菌を添加することにより立ち上げ期間を短縮することが可能であると考えられる。
【００１３】
また、これらの微生物を以下の様にして同定した。グラム染色の結果、Tol-1 株及びTol-3 株はグラム陽性であり、Tol-5 株はグラム陰性を示した。続いて、バイオログ（BIOLOG）社製の菌体同定装置（Microstation System ）を用いて代謝テスト及び同定を行った。試験に供する菌体はBUGM培地（Biolog Universal Growth Medium、BIOLOG社製）に植菌し、２５℃、２日間培養した。この菌体を、Tol-1 及びTol-3 はグラム陽性菌のための代謝テストプレートに植菌し、一方、Tol-5 はグラム陰性菌用代謝テストプレートに植菌し、２５℃で２４時間培養後、表１及び表２に示す結果を得た。その結果、Tol-1 株及びTol-3 株はロドコッカスエリスロポリス（Rhodococcus Erythropolis）、Tol-5 株はアシネートバクターゲノスピーシス（Acinetobacter Genospecies）10に分類された。そこで、Tol-1 株、Tol-3 株及びTol-5 株をそれぞれ、ロドコッカスエリスロポリス Tol-1、ロドコッカスエリスロポリス Tol-3及びアシネートバクターゲノスピーシス 10 Tol-5と命名した。
以上のうちTol-3株、 Tol-5株は特許微生物寄託センターにそれぞれＦＥＲＭＰ−１７１８７、ＦＥＲＭＰ−１７１８８として受託されている。
【００１４】
【表１】

【００１５】
【表２】

【００１６】
【実施例】
以下に実施例を挙げて本発明を説明するが、本発明はこれに限定されない。
〔実施例１〕
２００mlの液体培地（液体培地組成を表３に示した。）を注入した１リットル容の坂口フラスコに、トルエン１００mg、発泡性ウレタン約６ｇ（かさ容積：０．３６リットル）を添加し、微生物接種源として工場排水処理場の活性汚泥１mlを添加し、ゴム栓をして２５℃で、７日間ロータリー振とうにより培養した。このとき、気相中のトルエンは初期濃度に対して８１％減少していた。ここで、発泡性ウレタンを取り出し、新たに作成したトルエン１００mgを添加した液体培地に添加し、２５℃で、培養した。７日後に気相中のトルエン濃度を測定したところ９６％が減少していた。そこで、新たに調整した液体培地に該発泡性ウレタンを移し替えて、再度培養した。４日後に気相中のトルエン濃度を測定したところ、９８％が減少していた。そこで前回同様に新たな液体培地に該発泡性ウレタンを移し替えて培養した。
【００１７】
４日後の気相中のトルエン濃度は、検出限界（０．２ppm ）以下となった。再度、発泡性ウレタンを移し替えて培養した結果、２日後の気相中のトルエン濃度は検出限界以下となった。このとき、液体培地中に懸濁していた菌体量及び担体である発泡性ウレタンに付着していた菌体量を測定した結果、懸濁していた菌体は液体培地２００ml中に乾燥菌体で８０mg、付着していた菌体は発泡性ウレタン６ｇあたり９２０mgであり、大半は発泡性ウレタンに付着していた。このことから、トルエン分解微生物が担体表面に付着して集積培養されたことが分かった。
【００１８】
【表３】

【００１９】
続いて、上記と同様の液体培地を用意し、それぞれに菌体の付着した発泡性ウレタン（乾燥重量１ｇ相当）を添加し、新たに発泡性ウレタン５ｇを添加し、２５℃で培養した。３日後の気相中のトルエン濃度を測定したところ、いずれも９６％以上減少していた。
ここで、得られた菌体の付着した発泡性ウレタンを前述の実験装置に担体１として充填し、トルエン含有排ガスを通気してトルエン除去性能を明らかにした。実験条件の概要を表−４に示す。また実験装置のフローを図１に示す。
【００２０】
【表４】

【００２１】
トルエンガスは市販の薬品２に窒素ガス３をばっ気して発生させた。このガスをコンプレッサー４で発生させた空気で希釈して約１００ppm として、充填層５を通過させた。循環水貯槽６には培養液７を注入し、ポンプ８で汲み上げて、連続的に充填層上部から散水して微生物に栄養塩及び水分を供給した。培養液７には水道水に尿素１５０mg/リットル、りん酸水素二ナトリウム１０．２mg/リットル及び硫酸第一鉄５．４mg/リットルを添加したものを用いた。
注入ガス採取口９及び処理ガス採取口10からそれぞれのガスを採取し、ガスクロマトグラフを用いてトルエン濃度を分析し、流入ガス濃度を１００としてトルエン除去率を求めた。
その結果、図２に示すように、通気開始１時間後には除去率は３６％を示した、そして翌日には６８％に上昇し、３日後には８３％に達した。このことから、予め集積培養を行い、菌体を付着させた担体を用いることで、生物処理装置を短期間で馴致でき、高いトルエン除去性能が得られることが分かった。
【００２２】
〔実施例２〕
２００mlの液体培地を注入した１リットル容の坂口フラスコに約６ｇ（かさ容積：０．３６リットル）の発泡性ウレタンを添加し、Tol-5 株を接種し２５℃、２４時間ロータリー振とうにより培養した。その結果、培養液中には懸濁性分はほとんど無く、増殖菌体はほぼ全量が発泡性ウレタンに付着し、付着量は発泡性ウレタン１ｇあたり、乾燥菌体として８５mgを示した。続いて、Tol-5 株の付着した発泡性ウレタンを前述の実験装置に担体１として充填し、トルエン含有排ガスを通気してトルエン除去性能を明らかにした。実験条件及び実験装置のフローは実施例１と同じとした。
【００２３】
注入ガス採取口９及び処理ガス採取口10からそれぞれのガスを採取し、ガスクロマトグラフを用いてトルエン濃度を分析し、流入ガス濃度を１００としてトルエン除去率を求めた。
その結果、図３のグラフに示すように、通気開始直後には除去率は４０％を示した。そして翌日には７５％に上昇し、２日後には８４％に達した。このことから、Tol-5 を用いることで短期間で生物処理装置を馴致できることが確認された。
【００２４】
【発明の効果】
本発明の方法により、生物処理装置の処理能力を短時間で高めることができる。この効果により、運転開始時の該装置の馴致期間を短縮でき、またその他の様々な理由で処理性能が低下したときでも、短時間で該装置の処理性能を回復できる。
【図面の簡単な説明】
【図１】実験装置の１例のフロー図を示す。
【図２】実施例１における、担体表面に付着したトルエン分解集積培養微生物による除去率の経時変化を示すグラフ図である。
【図３】実施例２における、担体表面に付着したＴｏｌ−５株による除去率の経時変化を示すグラフ図である。
【符号の説明】
１：担体
２：トルエン
３：窒素ガス
４：コンプレッサー
５：充填層
６：循環水貯槽
７：培養液
８：ポンプ
９：注入ガス採取口
１０：処理ガス採取口[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a decomposition method and processing apparatus for volatile organic compounds, and in particular, volatilization of toluene, benzene, xylene, styrene, methanol, ethyl acetate, and the like discharged from a coating factory, a casting factory, a printing factory, a film manufacturing factory, and the like. This is a technology for treating exhaust gases containing volatile organic compounds and waste gases such as sewage or wastewater treatment plants.
[0002]
[Prior art]
Biological treatment of volatile organic compounds is a safe method with low running cost.
In the biological treatment method, a microorganism that decomposes a volatile organic compound to be treated (also referred to as VOC in the present specification) is required. Therefore, conventionally, activated sludge or the like was added as an inoculation source of microorganisms, and organisms suitable for decomposition of the treatment target substance were grown by acclimatization. Therefore, VOC was not sufficiently decomposed during the acclimatization period. The acclimatization period varies depending on the substance, but in the case of toluene, about 3 weeks were required.
Also, factory operations are usually not always continuous. May be suspended for nights, weekends and other holidays and inspections. Since VOC does not flow into the biological treatment apparatus during that time, it is predicted that a sufficient amount of removal performance cannot be obtained at start-up when the biomass decreases and VOC flows again. In particular, a long-term shutdown for several days or more may reduce the biological activity and require a period similar to that at the start of the operation to restore sufficient degradation performance.
[0003]
[Problems to be solved by the invention]
The present invention overcomes the drawbacks of the above-described conventional technology, increases the processing capacity of the biological treatment apparatus in a short time, and as a result, shortens the habituation period at the start of operation and processes in a short time when the processing performance deteriorates. An object of the present invention is to provide a method and a processing apparatus for decomposing volatile organic compounds that can recover performance.
[0004]
[Means for Solving the Problems]
The above object has been achieved by the following means.
(1) A resin medium that retains soil or activated sludge and microorganisms is added to a liquid medium containing a volatile organic compound as a main carbon source to be treated, followed by culturing. The operation of accumulating again in a liquid medium using the volatile organic compound as a main carbon source using the carrier as an inoculum is repeated several times, and the volatile organic compound is selectively highly adherent to the carrier. Characterized in that a biological treatment apparatus is provided in which a packed bed is filled with a resin carrier obtained by growing microorganisms that decompose microorganisms , and volatile organic compounds are allowed to pass through while maintaining the wet state by watering the packed bed. A method for decomposing volatile organic compounds.
(2) Add a resin carrier that holds soil or activated sludge and microorganisms to a liquid medium containing a volatile organic compound as a main carbon source to be treated, and take out the carrier after completion of the culture. The operation of re-accumulating and culturing again in a liquid medium containing the volatile organic compound as a main carbon source using the carrier as a new inoculum is repeated several times to separate the microorganisms selectively cultured on the carrier from the carrier, Supplying the separated microorganisms to a biological treatment apparatus equipped with a packed bed allows the packed bed to hold the microorganisms, and allows the volatile organic compound to pass through while maintaining the wet state by watering the packed bed. the method for decomposing a volatile organic compound you characterized.
[0005]
(3) The microorganism as described in (1) or (2) above, wherein the microorganism is Acinetobacter genosides 10 Tol-5 (FERM P-17188) or Rhodococcus erythropolis Tol-3 (FERM-17187) A method for decomposing volatile organic compounds.
(4) A resin medium that retains soil or activated sludge and microorganisms is added to a liquid medium containing a volatile organic compound as a main carbon source to be treated, followed by culturing. The operation of accumulating again in a liquid medium containing the volatile organic compound as a main carbon source using the carrier as a new inoculum is repeated several times to selectively decompose the organic compound with high adhesion to the carrier. A packed bed filled with a resin carrier obtained by growing microorganisms to grow, a watering device for spraying water to maintain the packed bed in a wet state, and an inlet and an outlet for passing exhaust gas containing a volatile organic compound An apparatus for treating exhaust gas containing a volatile organic compound, comprising the biological treatment apparatus provided.
(5) A resin medium that retains soil or activated sludge and microorganisms is added to a liquid medium containing a volatile organic compound as a main carbon source to be treated, followed by culturing. A new accumulation culture is repeated several times in a liquid medium using the carrier as an inoculum and the volatile organic compound as a main carbon source, and microorganisms selectively cultured on the carrier are supplied to the packed bed. A packed bed having microorganisms that improve the removal rate in a short time, a watering device for spraying water to maintain the packed bed in a wet state, and an inlet and an outlet for passing exhaust gas containing a volatile organic compound An exhaust gas treatment apparatus containing a volatile organic compound, characterized in that a biological treatment apparatus is provided.
(6) The microorganism described in (4) or (5) above, wherein the microorganism is Acinetobacter genospipes 10 Tol-5 (FERM P-17188) or Rhodococcus erythropolis Tol-3 (FERM-17187) An exhaust gas treatment device containing a volatile organic compound.
[0006]
The decrease in processing capacity as in the above-described conventional technology is caused by an absolute shortage of the amount of microorganisms having the ability to decompose the components to be processed in each exhaust gas. Accordingly, there is a possibility that a predetermined removal performance can be obtained in a short period of time by supplying the decomposition microorganism of the component to be processed into the apparatus.
A VOC-decomposing microorganism can be obtained by accumulating and culturing in a liquid medium using a mixed microorganism such as soil and activated sludge as a microorganism inoculation source and a VOC component to be treated as a carbon source. However, in the biological treatment equipment, microorganisms attached to a specific carrier (hereinafter also referred to as a filler) decompose the target component, so microorganisms that do not have the ability to adhere to the carrier cannot remain in the packed bed and have high processing performance. I can not expect. In addition, a microorganism having a high VOC degrading ability is highly likely to improve the processing performance of the apparatus. Therefore, the microorganisms added to the biological treatment apparatus are required to have an ability to adhere to a carrier and a high VOC degradation performance. Therefore, in the present invention, microorganisms having these properties are selectively cultured in large quantities and added to a biological treatment apparatus. Specifically, a microorganism having both of these properties efficiently cultured by some method from various microorganism groups such as activated sludge, or a purely isolated microorganism that has been revealed to have these properties, Alternatively, a microorganism mixture is cultured and added.
[0007]
In the above methods (1) to (6) , the carrier for holding the microorganism may be a resin such as polyurethane, polypropylene, polyvinylidene chloride, and acrylic. Since these have high air permeability, they are useful as carriers, but there is a problem that the performance of the apparatus does not improve because of low adhesion of microorganisms. Therefore, a technology for efficiently using microorganisms with high adhesion to these resins was developed. The point of time when the microorganisms are added to the packed bed of the biological treatment apparatus is preferably when the operation of the biological treatment apparatus starts or when the capacity of the biological treatment apparatus decreases. When microorganisms are added to the packed bed of the biological treatment apparatus at the start of operation of the biological treatment apparatus or when the capacity of the biological treatment apparatus is reduced, the following microorganisms may be used. That is, a volatile organic compound is added to a liquid medium containing a specific carrier as a main carbon source and cultured. In a liquid medium containing a volatile organic compound as a main carbon source using the carrier after the cultivation as an inoculum. The operation of repeated enrichment culture is repeated several times, and a selective enrichment culture is added.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the invention will be described below.
FIG. 1 is a flow diagram of an experimental apparatus suitable for practicing the present invention.
The experimental apparatus is filled with the carrier 1 to which the microbial cells adhere, and the toluene-containing exhaust gas is ventilated. The toluene gas is generated, for example, by aerating nitrogen gas 3 to a commercially available liquid toluene chemical 2. This gas is diluted with air generated by the compressor 4 and passed through the packed bed 5. A culture solution 7 is injected into the circulating water storage tank 6, pumped up by a pump 8, and continuously or intermittently sprinkled from the upper part of the packed bed to supply nutrient salts and moisture to the microorganisms. As the culture solution 7, tap water to which urea, disodium hydrogen phosphate, ferrous sulfate or the like is added is used.
[0009]
The microorganism to be attached to the carrier 1 is not particularly limited as long as it has a selective attachment ability to the carrier and can decompose volatile organic compounds , but it is not limited to Acynate Bacter genopesis 10 Tol-5 (FERM P-17188). Or Rhodococcus erythropolis Tol-3 (FERM P-17187).
The inventor added a microorganism inoculation source such as activated sludge and soil to a liquid medium containing the substance to be treated as the main carbon source, and simultaneously added the carrier 1 and cultured. After completion of the culture, the carrier 1 was taken out and cultured again in a medium having the same composition using the carrier 1 with microorganisms attached as an inoculum. As a result of repeating this operation several times, almost no suspension due to microbial cells was observed in the liquid after culturing, and the toluene-degrading microorganisms adhered to the carrier 1 and grew. Moreover, the decrease rate of toluene in the culture flask was gradually increased, suggesting that microorganisms having high toluene decomposing ability were accumulated. Therefore, the carrier 1 to which the bacterial cells were attached was filled in an experimental apparatus, and exhaust gas containing toluene was continuously vented to track changes in the treatment performance at the beginning of the experiment. As a result, a high removal performance was obtained 2 days after the start of the experiment, so that the above-mentioned method has the ability to adhere to the carrier 1 and can be acclimatized in a short period of time by using a microorganism having a high toluene removal ability. I understood that.
[0010]
In addition, a microorganism inoculation source such as activated sludge and soil is added to the packed bed of the carrier 1 for supporting the microorganisms, and the exhaust gas is simulated while continuously or intermittently sprinkling the nutrient solution in the packed bed. The gas created was aerated. Then, after about 2 months, the carrier 1 was taken out from the apparatus exhibiting high removal performance, and the attached microorganisms were peeled off and collected. This microflora has the above properties.
Furthermore, this microorganism is smeared and cultured on a plate medium containing the substance to be treated as the main carbon source, and three types of strains are isolated from the colonies that have emerged. The names are Tol-1, Tol-3 and Tol-5, respectively. It was a stock.
[0011]
When the ability of decomposing toluene per dry weight of each microorganism was measured by a batch experiment using a sealed vial, 2.2 mg-toluene / g-cell / min for Tol-1 strain and 2. for Tol-3 strain. 0 mg-toluene / g-bacteria / min, and Tol-5 strain showed 7.4 mg-toluene / g-bacteria / min. On the other hand, the sludge peeled off from the filler of the biological treatment apparatus that continuously decomposed toluene showed 0.6 mg-toluene / g-bacteria / min. Therefore, it was found that all the purely isolated microorganisms have a high ability to decompose toluene.
In addition, when Tol-5 strain is cultured in a liquid medium containing 2g / liter ethanol as the main carbon source in the presence of a filler (at 25 ° C, rotary shaking), a maximum of 140mg of bacterial cells per gram of filler adheres. did.
[0012]
Therefore, the experimental material was filled with a filler with bacterial cells attached, the experiment was started, and the initial treatment performance was followed up. After 2 days, high removal performance was obtained. It turned out that it can be adapted in a short time by using.
Furthermore, it was found that Tol-5 strain can decompose at least m-xylene, p-xylene, styrene, benzene, diethyl ether, ethyl acetate and ethanol in addition to toluene. Therefore, when treating these substances, it is considered that the start-up period can be shortened by adding this bacterium at the start of operation.
[0013]
Moreover, these microorganisms were identified as follows. As a result of Gram staining, Tol-1 and Tol-3 strains were Gram positive, and Tol-5 strain was Gram negative. Subsequently, a metabolic test and identification were carried out using a cell identification device (Microstation System) manufactured by Biolog. The cells used for the test were inoculated in a BUGM medium (Biolog Universal Growth Medium, manufactured by BIOLOG) and cultured at 25 ° C. for 2 days. Tol-1 and Tol-3 were inoculated on a metabolic test plate for Gram-positive bacteria, while Tol-5 was inoculated on a metabolic test plate for Gram-negative bacteria at 25 ° C. for 24 hours. After culturing, the results shown in Table 1 and Table 2 were obtained. As a result, the Tol-1 and Tol-3 strains were classified as Rhodococcus Erythropolis, and the Tol-5 strain was classified as Acinetobacter Genospecies 10. Therefore, the Tol-1 strain, Tol-3 strain, and Tol-5 strain were named Rhodococcus erythropolis Tol-1, Rhodococcus erythropolis Tol-3, and Acynate Bacter genosposis 10 Tol-5, respectively.
Of these, the Tol-3 strain and Tol-5 strain are entrusted to the Patent Microorganism Depositary Center as FERMP-17187 and FERM P-17188, respectively.
[0014]
[Table 1]

[0015]
[Table 2]

[0016]
【Example】
Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto.
[Example 1]
To a 1 liter Sakaguchi flask into which 200 ml of liquid medium (liquid medium composition is shown in Table 3) was added, 100 mg of toluene and about 6 g of foamable urethane (bulk volume: 0.36 liter) were added to inoculate the microorganism. 1 ml of activated sludge from a factory wastewater treatment plant was added as a source, and a rubber stopper was attached, followed by cultivation at 25 ° C. by rotary shaking for 7 days. At this time, toluene in the gas phase decreased by 81% with respect to the initial concentration. Here, the foaming urethane was taken out, added to a liquid medium to which 100 mg of newly prepared toluene was added, and cultured at 25 ° C. After 7 days, the toluene concentration in the gas phase was measured and found to be 96% lower. Therefore, the foamable urethane was transferred to a newly prepared liquid medium and cultured again. When the concentration of toluene in the gas phase was measured after 4 days, 98% had decreased. Therefore, the foamable urethane was transferred to a new liquid medium and cultured as in the previous time.
[0017]
After 4 days, the toluene concentration in the gas phase was below the detection limit (0.2 ppm). Again, as a result of transferring the foamable urethane and culturing, the toluene concentration in the gas phase after 2 days was below the detection limit. At this time, as a result of measuring the amount of cells suspended in the liquid medium and the amount of cells attached to the foaming urethane as a carrier, the suspended cells were dried cells in 200 ml of the liquid medium. The microbial cells adhering to 80 mg were 920 mg per 6 g of foamable urethane, and most adhered to the foamable urethane. From this, it was found that toluene-degrading microorganisms were attached to the surface of the carrier and accumulated and cultured.
[0018]
[Table 3]

[0019]
Subsequently, a liquid medium similar to the above was prepared, and foamable urethane (corresponding to a dry weight of 1 g) to which the bacterial cells were attached was added to each, and 5 g of foamable urethane was newly added and cultured at 25 ° C. When the concentration of toluene in the gas phase after 3 days was measured, all were found to have decreased by 96% or more.
Here, the obtained foamed urethane with attached bacterial cells was filled as the carrier 1 in the above-described experimental apparatus, and the toluene-containing exhaust gas was ventilated to clarify the toluene removal performance. A summary of the experimental conditions is shown in Table-4. The flow of the experimental apparatus is shown in FIG.
[0020]
[Table 4]

[0021]
Toluene gas was generated by aerating nitrogen gas 3 to commercially available chemical 2. This gas was diluted with air generated by the compressor 4 to about 100 ppm and passed through the packed bed 5. The culture solution 7 was injected into the circulating water storage tank 6, pumped up by a pump 8, and continuously sprinkled from the upper part of the packed bed to supply nutrient salts and moisture to the microorganisms. The culture solution 7 used was tap water added with 150 mg / liter of urea, 10.2 mg / liter of disodium hydrogen phosphate and 5.4 mg / liter of ferrous sulfate.
Each gas was sampled from the inlet gas sampling port 9 and the processing gas sampling port 10, and the toluene concentration was analyzed using a gas chromatograph, and the toluene removal rate was determined with the inflowing gas concentration set to 100.
As a result, as shown in FIG. 2, the removal rate was 36% 1 hour after the start of aeration, and increased to 68% the next day and reached 83% after 3 days. From this, it was found that the biological treatment apparatus can be acclimatized in a short period of time and a high toluene removal performance can be obtained by using a carrier on which bacterial culture has been performed in advance and culture cells are attached.
[0022]
[Example 2]
Add about 6 g (bulk volume: 0.36 liters) of foaming urethane to a 1 liter Sakaguchi flask into which 200 ml of liquid medium has been injected, inoculate with Tol-5 strain, and culture by rotary shaking at 25 ° C for 24 hours. did. As a result, there was almost no suspendability in the culture solution, and almost all of the proliferating cells adhered to the foaming urethane, and the amount of adhesion was 85 mg as dry cells per 1 g of foaming urethane. Subsequently, foaming urethane with Tol-5 strain attached was filled in the above-mentioned experimental apparatus as carrier 1, and toluene-containing exhaust gas was ventilated to clarify the toluene removal performance. The experimental conditions and the flow of the experimental apparatus were the same as in Example 1.
[0023]
Each gas was sampled from the inlet gas sampling port 9 and the processing gas sampling port 10, and the toluene concentration was analyzed using a gas chromatograph, and the toluene removal rate was determined with the inflow gas concentration set to 100.
As a result, as shown in the graph of FIG. 3, the removal rate was 40% immediately after the start of ventilation. On the next day, it rose to 75% and reached 2% two days later. From this, it was confirmed that the biological treatment equipment can be acclimatized in a short time by using Tol-5.
[0024]
【The invention's effect】
By the method of the present invention, the treatment capacity of the biological treatment apparatus can be increased in a short time. Due to this effect, the acclimatization period of the apparatus at the start of operation can be shortened, and the processing performance of the apparatus can be recovered in a short time even when the processing performance deteriorates due to various other reasons.
[Brief description of the drawings]
FIG. 1 shows a flowchart of an example of an experimental apparatus.
FIG. 2 is a graph showing the change over time in the removal rate by the toluene-degrading and accumulating culture microorganism attached to the carrier surface in Example 1.
3 is a graph showing the change over time of the removal rate by Tol-5 strain attached to the carrier surface in Example 2. FIG.
[Explanation of symbols]
1: Carrier 2: Toluene 3: Nitrogen gas 4: Compressor 5: Packed bed 6: Circulating water storage tank 7: Culture solution 8: Pump 9: Injection gas sampling port 10: Process gas sampling port

Claims

Add a resin carrier to which soil or activated sludge and microorganisms are attached to a liquid medium containing a volatile organic compound as a main carbon source to be treated, and culture it. The operation of accumulating again in a liquid medium using the carrier as an inoculum and the volatile organic compound as a main carbon source is repeated several times to selectively decompose the volatile organic compound with high adhesion to the carrier. A volatile organic compound is provided with a biological treatment device in which a packed carrier is filled with a resin carrier obtained by growing microorganisms, and a volatile organic compound is allowed to pass through while being maintained in a wet state by watering the packed bed. Method for decomposing organic compounds.

Carrier resin to the liquid medium a subject to volatile organic compound processing a major carbon source attaching soil or activated sludge with microorganisms are cultured by adding newly the taken out carrier after the culture The operation of re-accumulating and culturing again in a liquid medium using the volatile organic compound as the main carbon source with the carrier as an inoculum was repeated several times to separate the microorganisms selectively cultured on the carrier from the carrier, and the separated By supplying microorganisms to a biological treatment apparatus equipped with a packed bed, the packed bed is held with microorganisms, and the volatile organic compound is allowed to pass through while sprinkling water on the packed bed and maintaining the wet state . the method for decomposing that volatile organic compounds.

3. The volatile organic compound according to claim 1, wherein the microorganism is Acinetobacter genospics 10 Tol-5 (FERM P-17188) or Rhodococcus erythropolis Tol-3 (FERM-17187). Disassembly method.

Add a resin carrier that retains soil or activated sludge and microorganisms to a liquid medium containing a volatile organic compound as a main carbon source to be treated, and culture. The operation of accumulating again in a liquid medium using the carrier as an inoculum and the volatile organic compound as a main carbon source is repeated several times to selectively remove microorganisms that have high adhesion to the carrier and decompose the organic compound. A biological layer comprising a packed bed filled with a resin carrier obtained by propagation, a watering device for spraying water to maintain the packed bed in a wet state, and an inlet and an outlet for passing an exhaust gas containing a volatile organic compound A processing apparatus for exhaust gas containing a volatile organic compound, characterized in that a processing apparatus is provided.

Add a resin carrier that retains soil or activated sludge and microorganisms to a liquid medium containing a volatile organic compound as a main carbon source to be treated, and culture. By repeating the operation of culturing again in a liquid medium containing the volatile organic compound as a main carbon source using the carrier as an inoculum, and supplying microorganisms selectively cultured on the carrier to the packed bed, Biological treatment comprising a packed bed with microorganisms that improves the removal rate in a short time, a sprinkler for sprinkling water to maintain the packed bed in a wet state, and an inlet and outlet for passing exhaust gas containing volatile organic compounds An exhaust gas treatment apparatus containing a volatile organic compound, characterized in that an apparatus is provided.

The volatile organic compound according to claim 4 or 5, wherein the microorganism is Acinetobacter genospics 10 Tol-5 (FERM P-17188) or Rhodococcus erythropolis Tol-3 (FERM-17187). An exhaust gas treatment apparatus containing