JP6968023B2 - In-situ purification method and in-situ purification device for contaminated soil or water - Google Patents

In-situ purification method and in-situ purification device for contaminated soil or water Download PDF

Info

Publication number
JP6968023B2
JP6968023B2 JP2018079154A JP2018079154A JP6968023B2 JP 6968023 B2 JP6968023 B2 JP 6968023B2 JP 2018079154 A JP2018079154 A JP 2018079154A JP 2018079154 A JP2018079154 A JP 2018079154A JP 6968023 B2 JP6968023 B2 JP 6968023B2
Authority
JP
Japan
Prior art keywords
water
mercury
contaminated
iron
contaminated soil
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
JP2018079154A
Other languages
Japanese (ja)
Other versions
JP2019181411A (en
Inventor
敦規 根岸
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hazama Ando Corp
Original Assignee
Hazama Ando Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hazama Ando Corp filed Critical Hazama Ando Corp
Priority to JP2018079154A priority Critical patent/JP6968023B2/en
Publication of JP2019181411A publication Critical patent/JP2019181411A/en
Application granted granted Critical
Publication of JP6968023B2 publication Critical patent/JP6968023B2/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Landscapes

  • Processing Of Solid Wastes (AREA)
  • Purification Treatments By Anaerobic Or Anaerobic And Aerobic Bacteria Or Animals (AREA)
  • Treatment Of Water By Oxidation Or Reduction (AREA)
  • Treatment Of Sludge (AREA)

Description

本発明は、汚染土壌または汚染水の原位置浄化方法および原位置浄化装置に関し、特に、水銀化合物および／または水銀イオンで汚染された汚染土壌または汚染水の原位置浄化方法および原位置浄化装置に関する。 The present invention relates to an in-situ purification method and an in-situ purification device for contaminated soil or contaminated water, and more particularly to an in-situ purification method and an in-situ purification device for contaminated soil or contaminated water contaminated with a mercury compound and / or mercury ion. ..

工場排水、工場跡地などに由来する汚染物質は、ＰＣＢ、ＢＨＣ、ＤＤＴ等の難分解性有機化合物、鉄、クロム、マンガン、亜鉛、水銀等の金属イオン等多岐に渡り種々のものが存在しており、工業排水の浄化および工場跡地からの汚染物質の拡散防止の観点から、それらの汚染物質は除去されなければならない。 There are a wide variety of pollutants derived from factory wastewater, factory sites, etc., including persistent organic compounds such as PCB, BHC, and DDT, and metal ions such as iron, chromium, manganese, zinc, and mercury. From the standpoint of purifying industrial wastewater and preventing the spread of pollutants from the site of the factory, those pollutants must be removed.

上記汚染物質に含まれる水銀について、従来、出願人は微生物を用いた水銀の無毒化・除去方法を特許文献１において提案している。特許文献１は、水銀化合物および／または水銀イオンで汚染された土壌または汚染水に、水銀耐性鉄酸化細菌および二価の鉄イオンを加えて培養する汚染土壌または汚染水の浄化方法を開示する。 Regarding mercury contained in the above pollutants, the applicant has conventionally proposed a method for detoxifying and removing mercury using microorganisms in Patent Document 1. Patent Document 1 discloses a method for purifying contaminated soil or contaminated water in which mercury-resistant iron-oxidizing bacteria and divalent iron ions are added to cultivate soil or contaminated water contaminated with a mercury compound and / or mercury ions.

特許文献１に開示された汚染土壌または汚染水の浄化方法によれば、水銀耐性の鉄酸化細菌は鉄の酸化だけでなく、水銀イオン（Ｈｇ２＋）の金属水銀（Ｈｇ０）への還元能を有することから、水銀耐性鉄酸化細菌の培養とともに鉄イオンが酸化されることで、水銀イオンが金属水銀に還元されて気化し、水銀化合物および／または水銀イオンで汚染された土壌または汚染水が浄化される。 According to the method for purifying contaminated soil or contaminated water disclosed in Patent Document 1, mercury-resistant iron-oxidizing bacteria not only oxidize iron but also reduce mercury ions (Hg 2+ ) to metallic mercury (Hg 0 ). By oxidizing iron ions with the culture of mercury-resistant iron-oxidizing bacteria, mercury ions are reduced to metallic mercury and vaporized, and soil or contaminated water contaminated with mercury compounds and / or mercury ions is released. Be purified.

特許第４５７８５９７号公報Japanese Patent No. 4578597

しかしながら、特許文献１の水銀化合物および／または水銀イオンで汚染された土壌等の浄化方法によれば、直接水銀耐性鉄酸化細菌および二価の鉄イオンを添加するという簡単な方法で土壌中の水銀イオンの還元・気化が促されるものの、水銀耐性の鉄酸化細菌は、二価の鉄イオンを分子状酸素により三価鉄イオンに酸化し、そのエネルギーを利用して炭酸固定を行う化学合成無機酸化細菌であることから、当該鉄酸化細菌の活性を高めるためには浄化対象の汚染土壌中または地下水中の環境を好気的な状態にする必要がある。 However, according to the method for purifying soil contaminated with a mercury compound and / or mercury ion in Patent Document 1, mercury in the soil is directly added by a mercury-resistant iron-oxidizing bacterium and divalent iron ion. Although the reduction and vaporization of ions are promoted, mercury-resistant iron-oxidizing bacteria oxidize divalent iron ions to trivalent iron ions with molecular oxygen and use the energy to fix carbon dioxide chemically synthesized inorganic oxidation. Since it is a bacterium, it is necessary to make the environment in the contaminated soil or groundwater to be purified aerobic in order to increase the activity of the iron-oxidizing bacterium.

また、鉄酸化細菌は炭酸を固定することで生育することから、炭素源のない環境では生育することができない。 In addition, iron-oxidizing bacteria cannot grow in an environment without a carbon source because they grow by fixing carbonic acid.

したがって、浄化対象の環境によっては水銀耐性鉄酸化細菌の生育が悪く、浄化対処の土壌や地下水中から水銀の除去がうまく進まないことも懸念された。 Therefore, there was concern that the growth of mercury-resistant iron-oxidizing bacteria would be poor depending on the environment to be purified, and that mercury could not be successfully removed from the soil or groundwater to be purified.

本発明は、上記課題に鑑みてなされたものであり、その目的は、水銀耐性鉄酸化細菌を用いたバイオオーグメンテーションにおいて、浄化対象中の酸素および炭素環境に依らず良好な水銀の除去を可能とする汚染土壌または汚染水の浄化方法および浄化装置を提供することにある。 The present invention has been made in view of the above problems, and an object thereof is to remove good mercury regardless of the oxygen and carbon environment in the purification target in bio-augmentation using mercury-resistant iron-oxidizing bacteria. To provide a method and device for purifying contaminated soil or water that enables it.

上記目的を達成するための請求項１に記載の発明は、水銀化合物および／または水銀イオンで汚染された汚染土壌または汚染水を原位置で浄化する方法であって、水銀耐性鉄酸化細菌、３価未満の酸化数の鉄を含む鉄源、無機炭素源および酸素含有微細気泡を含む水銀耐性鉄酸化細菌含有水を前記汚染土壌または汚染水に供給する水銀耐性鉄酸化細菌含有水供給工程を含むことを特徴とする。 The invention according to claim 1 for achieving the above object is a method for purifying contaminated soil or contaminated water contaminated with a mercury compound and / or mercury ions in situ, wherein mercury-resistant iron-oxidizing bacteria, 3. Includes a mercury-resistant iron-oxidizing bacterium-containing water supply step that supplies mercury-resistant iron-oxidizing bacterium-containing water containing an iron source containing iron with an oxidation number less than the valence, an inorganic carbon source, and oxygen-containing microbubbles to the contaminated soil or contaminated water. It is characterized by that.

この構成によれば、水銀耐性鉄酸化細菌および３価未満の酸化数の鉄を含む鉄源と共に、無機炭素源および酸素含有微細気泡を含む水銀耐性鉄酸化細菌含有水が汚染土壌または汚染水に供給されることから、浄化対象の汚染土壌中または地下水中の環境を好気的且つ炭素源が豊富な状態とすることができる。これにより、水銀耐性鉄酸化細菌による鉄の酸化および炭素固定が進み、水銀イオンの金属水銀への還元・気化が促進され、汚染土壌または汚染水の浄化が進む。 According to this configuration, mercury-resistant iron-oxidizing bacteria-containing water containing an inorganic carbon source and oxygen-containing microbubbles, along with an iron source containing mercury-resistant iron-oxidizing bacteria and iron with an oxidation number of less than trivalent, becomes contaminated soil or contaminated water. Since it is supplied, the environment in the contaminated soil or groundwater to be purified can be made aerobic and rich in carbon sources. This promotes the oxidation and carbon fixation of iron by mercury-resistant iron-oxidizing bacteria, promotes the reduction and vaporization of mercury ions to metallic mercury, and promotes the purification of contaminated soil or contaminated water.

本発明の汚染土壌または汚染水の原位置浄化方法の好ましい態様は以下のとおりである。 A preferred embodiment of the method for in-situ purification of contaminated soil or contaminated water of the present invention is as follows.

（１）微細気泡含有水供給工程後、汚染土壌または汚染水中から還元気化された水銀を含む水銀含有水を回収する回収工程をさらに含む。
（２）酸素含有微細気泡が、発生時の直径が５０μｍ以下のマイクロバブルである。
（３）３価未満の酸化数の鉄を含む鉄源が硫酸第一鉄である。
（４）無機炭素源が二酸化炭素であり、酸素含有微細気泡中の酸素が大気に含まれる酸素である。
（５）微細気泡含有水供給工程における無機炭素源の添加量が、汚染土壌または汚染水の酸化還元電位が−６００ｍＶ以上８００ｍＶ未満となるように調整される。 (1) After the process of supplying water containing fine bubbles, a recovery step of recovering mercury-containing water containing reduced vaporized mercury from contaminated soil or contaminated water is further included.
(2) The oxygen-containing microbubbles are microbubbles having a diameter of 50 μm or less at the time of generation.
(3) The iron source containing iron having an oxidation number less than trivalent is ferrous sulfate.
(4) The inorganic carbon source is carbon dioxide, and the oxygen in the oxygen-containing fine bubbles is oxygen contained in the atmosphere.
(5) The amount of the inorganic carbon source added in the process of supplying water containing fine bubbles is adjusted so that the redox potential of the contaminated soil or contaminated water is -600 mV or more and less than 800 mV.

また、上記目的は、水銀化合物および／または水銀イオンで汚染された汚染土壌または汚染水を原位置で浄化する汚染土壌または汚染水の原位置浄化装置であって、水銀耐性鉄酸化細菌、３価未満の酸化数の鉄を含む鉄源、無機炭素源および酸素含有微細気泡を含む微細気泡含有水を前記汚染土壌または汚染水に供給する供給手段と、前記微細気泡含有水が供給された汚染土壌または汚染水中から還元気化された水銀を含む水銀含有水を回収する回収手段と、を有することを特徴とする汚染土壌または汚染水の原位置浄化装置によっても達成される。 Further, the above object is an in-situ purification device for in-situ purification of contaminated soil or contaminated water contaminated with mercury compounds and / or mercury ions, and is a mercury-resistant iron-oxidizing bacterium, trivalent. A supply means for supplying the contaminated soil or contaminated water with an iron source containing iron having an oxidation number of less than, an inorganic carbon source, and fine bubble-containing water containing oxygen-containing fine bubbles, and a contaminated soil to which the fine bubble-containing water is supplied. It is also achieved by an in-situ purification device for contaminated soil or contaminated water, which comprises a recovery means for recovering mercury-containing water containing reduced vaporized mercury from contaminated water.

本発明によれば、水銀耐性鉄酸化細菌および３価未満の酸化数の鉄を含む鉄源と共に、無機炭素源および酸素含有微細気泡を含む水銀耐性鉄酸化細菌含有水が汚染土壌または汚染水に供給されることから、浄化対象の汚染土壌中または地下水中の環境を好気的且つ炭素源が豊富な状態とすることができる。これにより、水銀耐性鉄酸化細菌による鉄の酸化および炭素固定が進み、水銀イオンの金属水銀への還元・気化が促進され、汚染土壌または汚染水の浄化が進む。したがって、浄化対象中の酸素および炭素環境に依らず水銀で汚染された土壌または汚染水の迅速に浄化することが可能となる。 According to the present invention, mercury-resistant iron-oxidizing bacteria-containing water containing an inorganic carbon source and oxygen-containing microbubbles, as well as an iron source containing mercury-resistant iron-oxidizing bacteria and iron with an oxidation number of less than trivalent, can be applied to contaminated soil or contaminated water. Since it is supplied, the environment in the contaminated soil or groundwater to be purified can be made aerobic and rich in carbon sources. This promotes the oxidation and carbon fixation of iron by mercury-resistant iron-oxidizing bacteria, promotes the reduction and vaporization of mercury ions to metallic mercury, and promotes the purification of contaminated soil or contaminated water. Therefore, it is possible to quickly purify soil or contaminated water contaminated with mercury regardless of the oxygen and carbon environment being purified.

本発明の汚染土壌または汚染水の原位置浄化装置の一例を示す模式図である。It is a schematic diagram which shows an example of the in-situ purification apparatus of contaminated soil or contaminated water of this invention. 鉄の電位−ｐＨ平衡図である。It is a potential-pH equilibrium diagram of iron. 各種炭酸水中の二酸化炭素濃度と酸化還元電位の測定結果を示した図である。It is a figure which showed the measurement result of the carbon dioxide concentration and the redox potential in various carbonated waters. 本発明の実施例に係る原位置浄化装置１００の模式図である。It is a schematic diagram of the in-situ purification apparatus 100 which concerns on embodiment of this invention.

＜汚染土壌または汚染水の原位置浄化方法＞
次に、本発明の汚染土壌または汚染水の原位置浄化方法を詳細に説明するが、本発明の方法は以下の方法に限られるものでは無い。本発明の汚染土壌または汚染水の原位置浄化方法は、汚染土壌および／または汚染水に、水銀耐性鉄酸化細菌、３価未満の酸化数の鉄を含む鉄源、無機炭素源および酸素含有微細気泡を含む水銀耐性鉄酸化細菌含有水を供給する。 <In-situ purification method for contaminated soil or contaminated water>
Next, the in-situ purification method for contaminated soil or contaminated water of the present invention will be described in detail, but the method of the present invention is not limited to the following methods. In the method for in-situ purification of contaminated soil or contaminated water of the present invention, the contaminated soil and / or contaminated water contains an iron source containing mercury-resistant iron-oxidizing bacteria and iron having an oxidation number of less than trivalent, an inorganic carbon source and oxygen-containing fine particles. Supply mercury-resistant iron-oxidizing bacteria-containing water containing bubbles.

浄化対象の汚染土壌としては、例えば、有機水銀系農薬で汚染された汚染土壌、金採掘で発生する汚染土壌、廃鉱山の汚染土壌、工場跡地の残留水銀を含む汚染土壌が挙げられる。また、浄化対象の汚染水としては、たとえば、工場廃液、上記各種汚染土壌からの水で飽和した地下水、工場廃液や上記各種汚染土壌から流出した汚染水が流入した池沼水が挙げられる。 Examples of the contaminated soil to be purified include contaminated soil contaminated with organic mercury-based pesticides, contaminated soil generated by gold mining, contaminated soil in abandoned mines, and contaminated soil containing residual mercury in the site of a factory. Examples of the contaminated water to be purified include factory effluent, groundwater saturated with water from the various contaminated soils, and pond water into which contaminated water flowing out of the factory effluent and the various contaminated soils has flowed.

水銀耐性鉄酸化細菌は、チオバチルス属細菌の中の、還元型無機硫黄化合物またはＦｅ２＋をエネルギー源とする細菌、即ちアシディチオバチルス・フェロオキシダンス(Acidithiobacillus ferrooxidans）の一種であって、ｐＨ１〜４の範囲で、Ｆｅ２＋の存在下に、水銀イオンを還元して金属水銀に変化させる。 The mercury-resistant iron-oxidizing bacterium is a kind of acidithiobacillus ferrooxidans, which is a bacterium having a reduced inorganic sulfur compound or Fe 2+ as an energy source among the bacterium belonging to the genus Acidithiobacillus, and has a pH of 1 to 1. In the range of 4, in the presence of Fe 2+ , mercury ions are reduced to change to metallic mercury.

かかる水銀耐性鉄酸化細菌としては、発明者らが過去に単離した鉄酸化細菌（Acidithiobacillus ferrooxidans）の水銀耐性株であるＳＵＧ２−２株またはＭＯＮ−１株を用いることができる。 As the mercury-resistant iron-oxidizing bacterium, the SUG2-2 strain or the MON-1 strain, which are mercury-resistant strains of the iron-oxidizing bacteria (Acidithiobacillus ferrooxidans) isolated by the inventors in the past, can be used.

また、鉄酸化細菌は、酸性土壌中から容易に単離することができる。そして、単離された株の中には約２０％程度の割合で水銀耐性株が含まれていることから、培地に水銀を含ませることにより単離株の中から水銀耐性株のみを選択することができる。 In addition, iron-oxidizing bacteria can be easily isolated from acidic soil. Since mercury-resistant strains are contained in the isolated strains at a ratio of about 20%, only mercury-resistant strains are selected from the isolated strains by including mercury in the medium. be able to.

鉄酸化細菌の単離は、例えば、鉄を含んだ酸性鉱山土壌やその廃水中から鉄酸化細菌を採取し、二価鉄を含んだ無機塩培地（ｐＨ２．５）中で集積培養後、これを、培地を含む１％ジェランガムプレートに塗布してコロニーを形成させることにより得ることができる。 For the isolation of iron-oxidizing bacteria, for example, iron-oxidizing bacteria are collected from acidic mine soil containing iron and its waste water, and after enrichment culture in an inorganic salt medium containing divalent iron (pH 2.5), this is performed. Can be obtained by applying to a 1% gellan gum plate containing a medium to form colonies.

その後、水銀耐性株の選択は、得られた単離株に対して６μＭから２０μＭまで順次Ｈｇ２＋濃度を上昇させてＨｇ２＋イオンを添加した培地においてさらに培養することにより行うことができる。 Then, the selection of the mercury-resistant strain can be carried out by sequentially increasing the Hg 2+ concentration from 6 μM to 20 μM with respect to the obtained isolated strain and further culturing in a medium supplemented with Hg 2+ ions.

３価未満の酸化数の鉄を含む鉄源は、ゼロ価鉄、１価鉄、２価鉄などが挙げられるが、３価未満の鉄を含む鉄源であればこれに限られない。具体的には、金属鉄（０価鉄）、ＦｅＳＯ４、ＦｅＣｌ２、Ｆｅ（ＮＯ３）２、ＦｅＯ、ＦｅＳ、Ｆｅ（ＯＨ）２、ＦｅＣｏ３等（以上、２価鉄）およびこれらの２種以上の組み合わせを挙げることができるが、鉄酸化細菌（Acidithiobacillus ferrooxidans）が鉄および硫黄を酸化してエネルギーを得る生物であることから、ＦｅＳＯ４、ＦｅＳが好ましく、入手の容易さの観点からＦｅＳＯ４が特に好ましい。 Examples of the iron source containing iron having an oxidation number of less than trivalent include zero-valent iron, monovalent iron, divalent iron and the like, but the iron source is not limited to this as long as it is an iron source containing less than trivalent iron. Specifically, metallic iron (zero-valent iron), FeSO 4 , FeCl 2 , Fe (NO 3 ) 2 , FeO, FeS, Fe (OH) 2 , FeCo 3, etc. (above, divalent iron) and 2 of these. Although combinations of more than one species can be mentioned, FeSO 4 and FeS are preferable because iron-oxidizing bacteria (Acidithiobacillus ferrooxidans) are organisms that oxidize iron and sulfur to obtain energy, and FeSO is preferable from the viewpoint of availability. 4 is particularly preferable.

無機炭素源としては、ＣＯ２、Ｎａ２ＣＯ３、ＮａＨＣＯ３およびその２種以上の組み合わせが挙げられる。無機炭素源として大気中のＣＯ２そのまま用いることもできるし、炭素濃度の調整が必要な場合には、無機炭素源の濃度および量の調整が行われても良い。無機炭素源としては、酸素とともに微細気泡化させて水銀耐性鉄酸化細菌含有水中に分散させ得る観点から、気体の二酸化炭素であることが好ましい。 Examples of the inorganic carbon source include CO 2 , Na 2 CO 3 , NaHCO 3 and a combination thereof. As the inorganic carbon source, CO 2 in the atmosphere can be used as it is, or if it is necessary to adjust the carbon concentration, the concentration and amount of the inorganic carbon source may be adjusted. The inorganic carbon source is preferably gaseous carbon dioxide from the viewpoint that it can be atomized together with oxygen and dispersed in mercury-resistant iron-oxidizing bacteria-containing water.

酸素含有微細気泡は、酸素を含有する微細気泡である。ここで、本願明細書において、微細気泡とは直径が５０μｍ以下のマイクロバブルおよび直径１μｍ以下のナノバブルを含む。直径５０μｍ以下のマイクロバブルは、水中を上昇し、水面で破裂する直径５０μｍ超の通常の気泡とは異なり、水中で縮小して最後には消滅する。また、直径１μｍ以下のナノバブルは長期間にわたって水中に存在する性質を有する。 Oxygen-containing microbubbles are oxygen-containing microbubbles. Here, in the present specification, the microbubbles include microbubbles having a diameter of 50 μm or less and nanobubbles having a diameter of 1 μm or less. Microbubbles having a diameter of 50 μm or less rise in water and burst in water, unlike ordinary bubbles having a diameter of more than 50 μm, which shrink in water and finally disappear. In addition, nanobubbles with a diameter of 1 μm or less have the property of existing in water for a long period of time.

微細気泡中の酸素は、大気中の酸素から供給されてもよく、酸素ボンベから供給される高濃度酸素、およびこれらの混合であってもよいが、酸素濃度としては大気中の酸素濃度で十分であり、且つ経済的であることから、大気中の酸素から供給されることが好ましい。 The oxygen in the fine bubbles may be supplied from oxygen in the atmosphere, high-concentration oxygen supplied from an oxygen cylinder, or a mixture thereof, but the oxygen concentration in the atmosphere is sufficient as the oxygen concentration. It is preferable that it is supplied from oxygen in the atmosphere because it is economical.

また、微細気泡は、エジェクター方式、キャビテーション方式、旋回流方式、加圧溶解法等、公知の方法で発生させることができるが、ランニングコストの観点からキャビテーション方式で発生させることが好ましい。 Further, the fine bubbles can be generated by a known method such as an ejector method, a cavitation method, a swirling flow method, a pressure melting method, etc., but it is preferable to generate them by a cavitation method from the viewpoint of running cost.

キャビテーション方式の微細気泡は、例えば、株式会社サイエンス、株式会社プレスカ、株式会社ビーエルダイナミクス、株式会社ワイビーエム製の装置を用いて発生させることができる。 Cavitation-type fine bubbles can be generated using, for example, an apparatus manufactured by Science Co., Ltd., Presca Co., Ltd., BL Dynamics Co., Ltd., and YBM Co., Ltd.

次に、本発明の汚染土壌または汚染水の原位置浄化方法について説明する。 Next, the in-situ purification method for contaminated soil or contaminated water of the present invention will be described.

［水銀耐性鉄酸化細菌含有水供給工程］
水銀耐性鉄酸化細菌含有水供給工程では、水銀耐性鉄酸化細菌、３価未満の酸化数の鉄を含む鉄源、無機炭素源および酸素含有微細気泡を含む水銀耐性鉄酸化細菌含有水を原位置において汚染土壌または汚染水に供給する。 [Mercury-resistant iron-oxidizing bacteria-containing water supply process]
In the process of supplying water containing mercury-resistant iron-oxidizing bacteria, mercury-resistant iron-oxidizing bacteria-containing water containing iron sources containing iron having an oxidation number of less than trivalent, an inorganic carbon source, and oxygen-containing microbubbles are used in place. Supply to contaminated soil or contaminated water in.

水銀耐性鉄酸化細菌含有水中、水銀耐性鉄酸化細菌含有水１Ｌあたり水銀耐性鉄酸化細菌は０．０１〜１０ｇ（タンパク質量）で含まれ、好ましくは、０．０５〜５ｇ（タンパク質量）であり、特に好ましくは、０．５〜２ｇ（タンパク質量）である。測定は、血清アルブミンを用いて検量線を作成し、Ｌｏｗｒｙ法により定量した。 Mercury-resistant iron-oxidizing bacteria-containing water and mercury-resistant iron-oxidizing bacteria-containing water per liter of mercury-resistant iron-oxidizing bacteria are contained in an amount of 0.01 to 10 g (protein amount), preferably 0.05 to 5 g (protein amount). Particularly preferably, it is 0.5 to 2 g (protein amount). For the measurement, a calibration curve was prepared using serum albumin and quantified by the Lowry method.

３価未満の酸化数の鉄を含む鉄源は、水銀耐性鉄酸化細菌含有水中、鉄源が硫酸第一鉄の場合、０．１〜５質量％、好ましくは０．５〜２質量％の範囲となるように添加される。硫酸第一鉄以外の鉄源が用いられる場合、硫酸第一鉄以外の鉄源は、上記硫酸第一鉄の添加濃度における鉄イオンのモル濃度（mol/L）範囲に相当する鉄イオンまたは鉄原子のモル濃度範囲となるように添加される。 The iron source containing iron having an oxidation number of less than trivalent is 0.1 to 5% by mass, preferably 0.5 to 2% by mass when the iron source is ferrous sulfate in mercury-resistant iron-oxidizing bacteria-containing water. It is added so as to be in the range. When an iron source other than ferrous sulfate is used, the iron source other than ferrous sulfate is iron ion or iron corresponding to the molar concentration (mol / L) range of iron ions in the above ferrous sulfate addition concentration. It is added so as to be in the molar concentration range of the atom.

無機炭素源は、無機炭素源が気体の二酸化炭素である場合、０．０３〜１．０体積％濃度の二酸化炭素が、好ましくは、０．１〜１．０体積％濃度の二酸化炭素が用いられる。無機炭素源として、二酸化炭素以外の無機炭素源が用いられる場合、二酸化炭素以外の無機炭素源（例えば、Ｎａ２ＣＯ３、ＮａＨＣＯ３）は、前記体積％濃度で二酸化炭素が供給された場合における水銀耐性鉄酸化細菌含有水中の炭素のモル濃度（mol/L）範囲に相当する炭素のモル濃度範囲となるように水銀耐性鉄酸化細菌含有水に添加される。 When the inorganic carbon source is gaseous carbon dioxide, the inorganic carbon source uses carbon dioxide having a concentration of 0.03 to 1.0% by volume, preferably carbon dioxide having a concentration of 0.1 to 1.0% by volume. Be done. As inorganic carbon source, if the inorganic carbon source other than carbon dioxide are used, inorganic carbon source other than carbon dioxide (e.g., Na 2 CO 3, NaHCO 3 ) is in the case where carbon dioxide in said volume% concentration was fed It is added to the mercury-resistant iron-oxidizing bacteria-containing water so as to have a carbon molar concentration range corresponding to the carbon-molar concentration (mol / L) range in the mercury-resistant iron-oxidizing bacteria-containing water.

水銀耐性鉄酸化細菌含有水の汚染土壌への供給は、例えば、注入井戸を用いて行うことができ、汚染土壌が土壌の表層領域である場合には、表層領域を重機で撹拌しつつ水銀耐性鉄酸化細菌含有水を供給してもよい。 Supply of mercury-resistant iron-oxidizing bacteria-containing water to contaminated soil can be performed, for example, by using an injection well. Water containing iron-oxidizing bacteria may be supplied.

また、水銀耐性鉄酸化細菌含有水の汚染水への供給は、工場廃液や池沼水のような場合には直接供給することができ、地下水のような場合には、注入井戸を用いて供給することができる（以上、水銀耐性鉄酸化細菌含有水供給工程）。 In addition, mercury-resistant iron-oxidizing bacteria-containing water can be supplied directly to contaminated water, such as factory effluent and pond water, and in the case of groundwater, it is supplied using an injection well. (The above is a process of supplying water containing mercury-resistant iron-oxidizing bacteria).

本発明に係る汚染土壌または汚染水の原位置浄化方法によれば、汚染土壌および汚染水中に、水銀耐性鉄酸化細菌および３価未満の酸化数の鉄を含む鉄源だけでなく、酸素含有微細気泡および無機炭素源が供給されることで、汚染土壌および汚染水中に炭素源が乏しいか、あるいは酸素が少ない状況であっても水銀耐性鉄酸化細菌の活性を高い状態で維持することが可能となり、水銀イオン（Ｈｇ２＋）の金属水銀（Ｈｇ０）への還元、および金属水銀の気化により、浄化対象中の酸素および炭素環境にかかわらず、水銀化合物および／または水銀イオンで汚染された土壌または汚染水の迅速な浄化が可能となる。 According to the method for in-situ purification of contaminated soil or contaminated water according to the present invention, not only an iron source containing mercury-resistant iron-oxidizing bacteria and iron having an oxidation number of less than trivalent in the contaminated soil and contaminated water, but also oxygen-containing fine particles The supply of bubbles and inorganic carbon sources makes it possible to maintain high activity of mercury-resistant iron-oxidizing bacteria even in situations where the carbon source is scarce or oxygen-poor in contaminated soil and water. , Mercury ion (Hg 2+ ) reduction to metallic mercury (Hg 0 ), and vaporization of metallic mercury, regardless of the oxygen and carbon environment being purified, the soil or soil contaminated with mercury compounds and / or mercury ions. It enables quick purification of contaminated water.

特に、好気的環境では無く、水銀耐性鉄酸化細菌の高活性が期待できないと予想される地中の汚染土壌や地下水である場合に、本方法による効果的な汚染土壌または汚染水の浄化効果が期待できる。 In particular, in the case of contaminated soil or groundwater in the ground where high activity of mercury-resistant iron-oxidizing bacteria is not expected to be expected in an aerobic environment, the effective purification effect of contaminated soil or contaminated water by this method. Can be expected.

＜汚染土壌または汚染水の原位置浄化装置＞
次に、本発明の汚染土壌または汚染水の原位置浄化方法を実施するための汚染土壌または汚染水の原位置浄化装置の一例を説明するが、原位置浄化装置についても、これに限られるものでは無い。 <In-situ purification device for contaminated soil or contaminated water>
Next, an example of an in-situ purification device for contaminated soil or contaminated water for implementing the in-situ purification method for contaminated soil or contaminated water of the present invention will be described, but the in-situ purification device is also limited to this. Not.

図１は、本発明の汚染土壌または汚染水の原位置浄化装置の一例を示す模式図である。 FIG. 1 is a schematic diagram showing an example of an in-situ purification device for contaminated soil or contaminated water of the present invention.

図１に示す汚染土壌または汚染水２の原位置浄化装置１０は、微細気泡含有水を前記汚染土壌または汚染水２に供給する供給手段と、微細気泡含有水が供給された汚染土壌または汚染水２中から還元気化された水銀を含む水銀含有水を回収する回収手段と、を有する。 The in-situ purification device 10 for the contaminated soil or contaminated water 2 shown in FIG. 1 has a supply means for supplying the contaminated soil or contaminated water 2 with fine bubble-containing water and a contaminated soil or contaminated water to which the fine bubble-containing water is supplied. 2. It has a recovery means for recovering mercury-containing water containing reduced vaporized mercury.

供給手段は、微細気泡含有水を汚染土壌または汚染水２に供給可能な手段であればどのようなものであってもよいが、例えば、混合槽２２と混合槽２２内の液を汚染土壌または汚染水２へと送液する送液手段２４と、を有する。 The supply means may be any means as long as it can supply the water containing fine bubbles to the contaminated soil or the contaminated water 2, and for example, the mixing tank 22 and the liquid in the mixing tank 22 may be supplied to the contaminated soil or the contaminated water 2. It has a liquid feeding means 24 for feeding the liquid to the contaminated water 2.

混合槽２２は、水銀耐性鉄酸化細菌、３価未満の酸化数の鉄を含む鉄源、無機炭素源および酸素含有微細気泡を混合する場となる。なお、水銀耐性鉄酸化細菌、無機炭素源および酸素含有微細気泡は混合槽２２に至る前に予備混合されていても良い。 The mixing tank 22 serves as a place for mixing mercury-resistant iron-oxidizing bacteria, an iron source containing iron having an oxidation number of less than trivalent, an inorganic carbon source, and oxygen-containing fine bubbles. The mercury-resistant iron-oxidizing bacteria, inorganic carbon source and oxygen-containing fine bubbles may be premixed before reaching the mixing tank 22.

送液手段２４は、非容積ポンプ、容積ポンプ、特殊型ポンプなどの公知のポンプの中から適宜に選択して用いることができる。 The liquid feeding means 24 can be appropriately selected and used from known pumps such as non-volumetric pumps, volumetric pumps, and special type pumps.

浄化対象が、地下水や、表層部ではなく地中に位置する土壌である場合には、注入井戸２６を用いて微細気泡含有水を浄化対象位置まで送り込むことができる。 When the purification target is groundwater or soil located in the ground instead of the surface layer portion, the fine bubble-containing water can be sent to the purification target position by using the injection well 26.

水銀耐性鉄酸化細菌については、混合槽２２で混合される前に、前培養を行っておくことが好ましい。水銀耐性鉄酸化細菌の前培養は、例えば、混合槽２２の上流に配置された混和槽２８で実施される。 For mercury-resistant iron-oxidizing bacteria, it is preferable to perform pre-culture before mixing in the mixing tank 22. Pre-culture of mercury-resistant iron-oxidizing bacteria is carried out, for example, in a mixing tank 28 arranged upstream of the mixing tank 22.

混和槽２８では、水銀耐性鉄酸化細菌の種菌が、所定のｐＨに調整された基本培地（液体）に添加され、培養される。培養温度は２０〜３０℃であり、混和槽２８中のｐＨは１〜４の範囲に維持される。 In the mixing tank 28, the inoculum of mercury-resistant iron-oxidizing bacteria is added to a basal medium (liquid) adjusted to a predetermined pH and cultured. The culture temperature is 20 to 30 ° C., and the pH in the mixing tank 28 is maintained in the range of 1 to 4.

基本培地としては、９Ｋ基本培地の他、NBRC Culture カタログに掲載されたMedium No.２３５およびMedium No.１３７９の培地等を適宜に用いることができる。 As the basal medium, in addition to the 9K basal medium, Medium No. 235 and Medium No. 1379 media listed in the NBRC Culture catalog can be appropriately used.

混和槽２８が設けられる場合、無機炭素源および酸素含有微細気泡は混合槽２２では無く混和槽２８に供給されることが、水銀耐性鉄酸化細菌の活動の活発化の観点から好ましい。 When the mixing tank 28 is provided, it is preferable that the inorganic carbon source and oxygen-containing fine bubbles are supplied to the mixing tank 28 instead of the mixing tank 22 from the viewpoint of activating the activity of mercury-resistant iron-oxidizing bacteria.

酸素含有微細気泡を発生させるために、混和槽２８に直接、または混和槽２８の上流に、微細気泡発生装置３０が設けられる。 In order to generate oxygen-containing fine bubbles, a fine bubble generator 30 is provided directly in the mixing tank 28 or upstream of the mixing tank 28.

微細気泡発生装置３０が大気を吸入することで、大気中の酸素が混和槽２８中に酸素が導入される。同時に、大気を用いることで、０．０３質量％の二酸化炭素を無機炭素源として混和槽２８中に供給することができる。 When the fine bubble generator 30 inhales the atmosphere, oxygen in the atmosphere is introduced into the mixing tank 28. At the same time, by using the atmosphere, 0.03% by mass of carbon dioxide can be supplied into the mixing tank 28 as an inorganic carbon source.

無機炭素源の供給濃度を高める場合は、大気に二酸化炭素を混合した気体を微細気泡発生装置３０に吸引させることで実施できる。この場合、二酸化炭素は、例えば、液化炭酸ガスを充填した容器から供給することができる。 The increase in the supply concentration of the inorganic carbon source can be carried out by sucking a gas in which carbon dioxide is mixed with the atmosphere into the fine bubble generator 30. In this case, carbon dioxide can be supplied, for example, from a container filled with liquefied carbon dioxide gas.

別の態様として、無機炭素源は、混合槽２２や混和槽２８に供給されてもよく、無機炭素源としてＮａ２ＣＯ３、ＮａＨＣＯ３が混合槽２２や混和槽２８に供給されてもよい。 In another embodiment, the inorganic carbon source may be supplied to the mixing tank 22 and mixing tank 28, Na 2 CO 3, NaHCO 3 as an inorganic carbon source may be supplied to the mixing tank 22 and mixing tank 28.

回収手段は、微細気泡含有水が供給された汚染土壌または汚染水２から還元気化された水銀を含む水銀含有水を回収可能な手段であればどのようなものであってもよいが、例えば、汚染土壌または汚染水２から還元気化された水銀を含む水銀含有水を回収する回収槽４１と、汚染土壌または汚染水２からの水銀含有水を回収槽４１へと吸引する吸引手段４２と、を有する。 The recovery means may be any means as long as it can recover the mercury-containing water containing mercury reduced and vaporized from the contaminated soil to which the fine bubble-containing water is supplied or the contaminated water 2. A recovery tank 41 for recovering mercury-containing water containing mercury reduced and vaporized from the contaminated soil or contaminated water 2, and a suction means 42 for sucking the mercury-containing water from the contaminated soil or contaminated water 2 into the recovery tank 41. Have.

吸引手段４２は、送液手段２４同様、公知のポンプを用いることができる。 As the suction means 42, a known pump can be used as in the liquid feeding means 24.

汚染土壌または汚染水の原位置浄化装置１０を用いた汚染土壌または汚染水２の原位置浄化方法においては、水銀耐性鉄酸化細菌含有水供給工程後、以下の回収工程が実施される。 In the in-situ purification method for contaminated soil or contaminated water 2 using the in-situ purification device 10 for contaminated soil or contaminated water, the following recovery step is carried out after the mercury-resistant iron-oxidizing bacteria-containing water supply step.

［回収工程］
本工程では、汚染土壌または汚染水２中から還元気化された水銀を含む水銀含有水を回収する。回収は、浄化対象が湖沼水や表層部の土壌である場合には、表層部の水を直接吸引することで行われる。しかし、水銀含有水を地下水や深層土壌から回収する必要がある場合には、回収井戸４４を土壌中に設け、回収井戸４４中に湧出した水銀含有水を吸引手段４２により吸引しても良い（以上、回収工程）。 [Recovery process]
In this step, mercury-containing water containing reduced vaporized mercury is recovered from the contaminated soil or the contaminated water 2. When the target of purification is lake water or surface soil, the recovery is performed by directly sucking the surface water. However, when it is necessary to recover the mercury-containing water from groundwater or deep soil, the recovery well 44 may be provided in the soil and the mercury-containing water discharged into the recovery well 44 may be sucked by the suction means 42 (. Above, the collection process).

本発明の汚染土壌または汚染水の原位置浄化装置１０およびこれを用いた汚染土壌または汚染水の原位置浄化方法によれば、還元気化した水銀が吸引手段４２を介して回収槽４１に回収されることから、汚染土壌中または汚染水中で気化した水銀が大気中に放出し、大気が汚染される虞もない。また、水銀含有水が回収槽４１中に回収されていることから、その後の処理も容易になる。 According to the in-situ purification device 10 for contaminated soil or contaminated water of the present invention and the in-situ purification method for contaminated soil or contaminated water using the same, the reduced vaporized mercury is recovered in the recovery tank 41 via the suction means 42. Therefore, there is no risk that mercury vaporized in contaminated soil or contaminated water will be released into the atmosphere and the air will be contaminated. Further, since the mercury-containing water is recovered in the recovery tank 41, the subsequent treatment becomes easy.

また、本発明においては、水銀耐性鉄酸化細菌の炭酸固定の活性を高めるために酸素含有微細気泡を鉄源と共に水銀耐性鉄酸化細菌含有水中に含ませているため、酸素濃度によってはこの酸素により鉄が３価の酸化数まで酸化され、鉄源の寿命が短くなることが懸念された。 Further, in the present invention, in order to enhance the activity of carbon dioxide fixation of the mercury-resistant iron-oxidizing bacteria, oxygen-containing fine bubbles are contained in the mercury-resistant iron-oxidizing bacteria-containing water together with the iron source. There was concern that iron would be oxidized to a trivalent oxidation number and the life of the iron source would be shortened.

図２は、鉄の電位−ｐＨ平衡図である。縦軸は標準酸化還元電位（V vs. SHE）であり、横軸はｐＨである。なお、本図は、Removal of ammonium, iron and manganese from potable water in biofiltration units: A review（Athanasia G. Tekerlekopoulouら著、Journal of Chemical Technology and Biotechnology、第８８巻第５号７５１〜７７３頁、２０１３年５月発行）の図２を引用し、一部追記を行ったものである。図示のように、水銀耐性鉄酸化細菌による水銀イオンの金属水銀への還元が期待できるｐＨ１〜４の範囲において、鉄は、水溶液中の酸化還元電位が約８００ｍＶとなると３価の酸化数で存在し、逆に、水溶液中の酸化還元電位が約−６００ｍＶを下回ると０価の酸化数で存在する（図２の破線で示す、ｐＨ１〜４の領域とＦｅ２＋の存在領域の重複領域を参照）。すなわち、水溶液中の酸化還元電位が−６００ｍＶ以上８００ｍＶ未満であることが、水溶液中に水銀耐性鉄酸化細菌が利用しやすい２価の酸化数の鉄イオンが存在するための好適な条件といえる。 FIG. 2 is a potential-pH equilibrium diagram of iron. The vertical axis is the standard redox potential (V vs. SHE), and the horizontal axis is pH. This figure shows the Removal of ammonium, iron and manganese from potable water in biofiltration units: A review (Athanasia G. Tekerlekopoulou et al., Journal of Chemical Technology and Biotechnology, Vol. 88, No. 5, pp. 751-773, 2013. Figure 2 (issued in May) is quoted, and some additions have been made. As shown in the figure, iron exists at a trivalent oxidation number when the redox potential in the aqueous solution is about 800 mV in the range of pH 1 to 4 where the reduction of mercury ions to metallic mercury by mercury-resistant iron-oxidizing bacteria can be expected. On the contrary, when the redox potential in the aqueous solution is lower than about -600 mV, it exists at a 0-valent oxidation number (see the overlapping region of the pH 1 to 4 region and the Fe 2+ existing region shown by the broken line in FIG. 2). ). That is, it can be said that the redox potential in the aqueous solution is −600 mV or more and less than 800 mV, which is a suitable condition for the presence of iron ions having a divalent oxidation number easily used by mercury-resistant iron-oxidizing bacteria in the aqueous solution.

また、図３は、各種炭酸水中の二酸化炭素濃度と酸化還元電位の測定結果を示した図である。具体的には、炭酸水製造装置で１００００、５０００、３０００、１０００、５００ｐｐｍに調整した炭酸水３００ｍｌをそれぞれ三角フラスコに入れ、酸化還元電位のプローブとともに密栓し、１分経過後の酸化還元電位を読み取ったものである（なお、二酸化炭素濃度は、赤外線分光分析で測定した）。 Further, FIG. 3 is a diagram showing the measurement results of the carbon dioxide concentration and the redox potential in various carbonated waters. Specifically, 300 ml of carbonated water adjusted to 10,000, 5,000, 3,000, 1,000, and 500 ppm by a carbonated water production device is placed in a triangular flask, sealed together with a probe having a redox potential, and the redox potential after 1 minute has passed. It was read (the carbon dioxide concentration was measured by infrared spectroscopic analysis).

図３によれば、炭酸水中の二酸化炭素濃度が高くなるにつれて酸化還元電位は低下する傾向にある。すなわち、水銀耐性鉄酸化細菌による鉄の酸化および水銀イオンの還元の場となる汚染土壌または汚染水の酸化還元電位が、鉄の酸化数が２価で存在する範囲、すなわち、−６００ｍＶ以上８００ｍＶ未満の範囲、好ましくは、−１００ｍＶ以上５００ｍＶ以下の範囲となるように、微細気泡含有水供給工程における無機炭素源の添加量が調整されることが好ましい。 According to FIG. 3, the redox potential tends to decrease as the carbon dioxide concentration in the carbonated water increases. That is, the redox potential of contaminated soil or contaminated water, which is a place for iron oxidation by mercury-resistant iron-oxidizing bacteria and reduction of mercury ions, is in the range where the oxidation number of iron exists in divalent range, that is, -600 mV or more and less than 800 mV. The amount of the inorganic carbon source added in the fine bubble-containing water supply step is preferably adjusted so as to be in the range of -100 mV or more, preferably 500 mV or less.

汚染土壌または汚染水２の酸化還元電位の測定は、酸化還元電位計の電極を直接汚染土壌若しくは汚染水に、または汚染土壌若しくは汚染水からサンプリングした液に挿入することにより、実施することができる。または、回収井戸４４を設ける場合には、回収井戸４４に、あるいはその下流に酸化還元電位計を設けることで測定することができる。 The measurement of the redox potential of the contaminated soil or contaminated water 2 can be carried out by inserting the electrode of the redox potential meter directly into the contaminated soil or contaminated water, or by inserting the solution sampled from the contaminated soil or contaminated water. .. Alternatively, when the recovery well 44 is provided, the measurement can be performed by providing a redox potential meter in or downstream of the recovery well 44.

無機炭素源の添加量の調整は、例えば、微細気泡発生装置３０に供給される炭酸ガスの供給量を増減することで実施することができ、また、混和層２８や混合槽２２にＮａ２ＣＯ３、ＮａＨＣＯ３を添加することで、あるいはその添加量を増減することで実施することができる。 The amount of the inorganic carbon source added can be adjusted, for example, by increasing or decreasing the amount of carbon dioxide gas supplied to the fine bubble generator 30, and Na 2 CO can be added to the mixing layer 28 or the mixing tank 22. 3. It can be carried out by adding NaHCO 3 or by increasing or decreasing the amount of the addition.

微細気泡含有水供給工程における無機炭素源の添加量が上記のとおりに調整されることで、浄化対象の汚染土壌または汚染水２の環境を好気的条件に維持しつつも添加された鉄源中の鉄の３価の酸化数への酸化を最小限に留めることができる。 By adjusting the amount of the inorganic carbon source added in the process of supplying water containing fine bubbles as described above, the iron source added while maintaining the environment of the contaminated soil or contaminated water 2 to be purified in aerobic conditions. Oxidation of the iron inside to the trivalent oxidation number can be minimized.

なお、本発明は上記実施の形態に限定されることはなく、発明の趣旨を逸脱しない範囲で種々変更可能である。 The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention.

例えば、無機炭素源の添加量の調整を実施するための手段として、汚染土壌または汚染水の原位置浄化装置１０に、汚染土壌または汚染水２の原位置、回収井戸あるいはその下流位置に設けられて汚染土壌または汚染水２の酸化還元電位を測定する酸化還元電位計と、無機炭素源の供給量を調整可能な無機炭素源供給部と、酸化還元電位計で測定された酸化還元電位の値に基づいて無機炭素源供給部における無機炭素源の供給量を増減制御する制御部と、を設けても良い。 For example, as a means for adjusting the amount of the inorganic carbon source added, the in-situ purification device 10 for the contaminated soil or the contaminated water is provided at the in-situ position of the contaminated soil or the contaminated water 2, a recovery well or a downstream position thereof. Oxidation-reduction potential meter that measures the oxidation-reduction potential of contaminated soil or contaminated water 2, an inorganic carbon source supply unit that can adjust the supply amount of the inorganic carbon source, and the value of the oxidation-reduction potential measured by the oxidation-reduction potential meter. A control unit for controlling the increase / decrease of the supply amount of the inorganic carbon source in the inorganic carbon source supply unit may be provided based on the above.

無機炭素源供給部としては、例えば、後述する実施例の微細気泡発生装置３０、経路１０４および開閉弁１０４ａが挙げられるがこれに限られるものではない。 Examples of the inorganic carbon source supply unit include, but are not limited to, the fine bubble generator 30, the path 104, and the on-off valve 104a of Examples described later.

また、制御部としては、ＣＰＵ、ＲＡＭ、ＲＯＭ等を備えたコンピュータが例示され、制御部は、予めＲＯＭ等に格納されたプログラムに基づき、上記制御を実行する。 Further, as the control unit, a computer equipped with a CPU, RAM, ROM, etc. is exemplified, and the control unit executes the above control based on a program stored in the ROM or the like in advance.

この構成によれば、酸化還元電位計で測定された汚染土壌または汚染水の酸化還元電位の値に基づき無機炭素源供給部で供給される二酸化炭素などの無機炭素源の濃度を増減調節することができるので、汚染土壌または汚染水２中における酸素による鉄の３価の酸化数への酸化を効果的に抑制することが可能となる。 According to this configuration, the concentration of an inorganic carbon source such as carbon dioxide supplied by the inorganic carbon source supply unit is increased or decreased based on the value of the redox potential of the contaminated soil or contaminated water measured by the redox potential meter. Therefore, it is possible to effectively suppress the oxidation of iron to the trivalent oxidation number by oxygen in the contaminated soil or the contaminated water 2.

さらに、汚染土壌または汚染水２から回収された水銀含有水を、水銀含有ガスと水銀以外の回収水とに分離することが好ましい。 Further, it is preferable to separate the mercury-containing water recovered from the contaminated soil or the contaminated water 2 into the mercury-containing gas and the recovered water other than mercury.

水銀含有ガスと水銀以外の回収水への分離は、重力分離器、遠心分離器、気液分離膜、減圧分離装置等の公知の気液分離装置やこれらの組み合わせを用いることができる。 For the separation of the mercury-containing gas and the recovered water other than mercury, a known gas-liquid separation device such as a gravity separator, a centrifuge, a gas-liquid separation membrane, a vacuum separation device, or a combination thereof can be used.

回収水は、混合槽２２や混和槽２８に返送され、希釈水として再利用することが好ましい。 It is preferable that the recovered water is returned to the mixing tank 22 or the mixing tank 28 and reused as diluted water.

一方、分離された水銀含有ガスは、活性炭吸着、過マンガン酸カリウム溶液での捕集、金、銀、スズ、銅、亜鉛等とのアマルガム反応を利用したアマルガム技術などの水銀除去処理を施すことで水銀を除去し、水銀が除去された処理ガスのみが大気中に放出されることが好ましい。 On the other hand, the separated mercury-containing gas is subjected to mercury removal treatment such as adsorption of activated charcoal, collection with potassium permanganate solution, and amalgam technology using amalgam reaction with gold, silver, tin, copper, zinc, etc. It is preferable that the mercury is removed by the method and only the processing gas from which the mercury is removed is released into the atmosphere.

過マンガン酸カリウム溶液中に水銀を捕集した場合には、この水銀を還元することでさらに水銀を放出して再利用することが可能となる。 When mercury is collected in a potassium permanganate solution, it is possible to further release and reuse the mercury by reducing the mercury.

以下、本発明をさらに実施例により詳細に説明する。 Hereinafter, the present invention will be described in more detail with reference to Examples.

図４は、本発明に係る汚染土壌または汚染水の原位置浄化装置１００の具体的な設計例を示す模式図である。図４において上述の図１に示した原位置浄化装置１０と同様の要素には同じ符号を付して説明を省略する。 FIG. 4 is a schematic diagram showing a specific design example of the in-situ purification device 100 for contaminated soil or contaminated water according to the present invention. In FIG. 4, the same elements as those of the in-situ purification device 10 shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

本実施例に係る原位置浄化装置１００は、水銀耐性鉄酸化細菌含有水が調製される混合槽２２、混合槽２２に隣接する混和槽２８および汚染土壌または汚染水から回収された水銀含有水が貯留される回収槽４１を有する。 In the in-situ purification device 100 according to the present embodiment, the mixing tank 22 in which the mercury-resistant iron-oxidizing bacteria-containing water is prepared, the mixing tank 28 adjacent to the mixing tank 22, and the mercury-containing water recovered from the contaminated soil or the contaminated water are contained. It has a collection tank 41 to be stored.

微細気泡発生装置３０は混和槽２８の上流に設けられており、微細気泡発生装置３０には大気と二酸化炭素の混合気体を供給可能である。また、それぞれの経路１０２と経路１０４に設けられた開閉弁１０２ａ、１０４ａの開度を調整することで微細気泡発生装置３０に供給される酸素濃度および二酸化炭素濃度を調整可能である。 The fine bubble generator 30 is provided upstream of the mixing tank 28, and can supply a mixed gas of the atmosphere and carbon dioxide to the fine bubble generator 30. Further, the oxygen concentration and the carbon dioxide concentration supplied to the fine bubble generator 30 can be adjusted by adjusting the opening degrees of the on-off valves 102a and 104a provided in the respective paths 102 and 104.

混合槽２８は経路１０６を介して注入井戸２６に接続されている。注入井戸２６と混相槽２８の間には、注入ポンプ２４のほか、開閉弁１０６ａ、添加メータ１０６ｂが設けられており、これにより、水銀耐性鉄酸化細菌含有水の供給量を管理できる。 The mixing tank 28 is connected to the injection well 26 via a path 106. In addition to the injection pump 24, an on-off valve 106a and an addition meter 106b are provided between the injection well 26 and the phase mixing tank 28, whereby the supply amount of mercury-resistant iron-oxidizing bacteria-containing water can be controlled.

回収槽４１の下流には、気液分離槽１１０が設けられており、回収槽４１と気液分離槽１１０との間には流量計１２８が介在する。 A gas-liquid separation tank 110 is provided downstream of the recovery tank 41, and a flow meter 128 is interposed between the recovery tank 41 and the gas-liquid separation tank 110.

気液分離槽１１０の下流には、分離された気体が排出される経路１１２と気体が除去された処理水が排出される経路１１４がそれぞれ接続されており、経路１１４は混和槽２８へと接続される経路１１６および混合槽２２へと接続される経路１１８へと分岐する。経路１１６および経路１１８には、それぞれ開閉弁１１６ａ，１１８ａが設けられており、処理水の流入方向および流入量を調整可能である。 A path 112 through which the separated gas is discharged and a path 114 in which the treated water from which the gas has been removed are discharged are connected to the downstream of the gas-liquid separation tank 110, and the path 114 is connected to the mixing tank 28. It branches to the route 116 to be connected to the route 116 and the route 118 connected to the mixing tank 22. On-off valves 116a and 118a are provided in the path 116 and the path 118, respectively, and the inflow direction and the inflow amount of the treated water can be adjusted.

また、経路１１２には、ブロア１２０が設けられ、その下流に活性炭吸着塔１２２、開閉弁１１２ａ、水銀吸着塔１２４および過マンガン酸カリウム溶液の水銀トラップ１２６からなる水銀除去装置が順に設けられている。 Further, a blower 120 is provided in the path 112, and a mercury removing device including an activated carbon adsorption tower 122, an on-off valve 112a, a mercury adsorption tower 124, and a mercury trap 126 of a potassium permanganate solution is sequentially provided downstream thereof. ..

本実施例に係る汚染土壌または汚染水の原位置浄化装置１００によれば、無機炭素源および酸素含有微細気泡を含む水銀耐性鉄酸化細菌含有水が汚染土壌または汚染水２に供給されることから、好気的且つ無機炭素源が豊富な環境下で水銀耐性鉄酸化細菌による鉄の酸化、炭素固定および水銀の還元が促進され、汚染土壌または汚染水の浄化が進む。 According to the in-situ purification device 100 for contaminated soil or contaminated water according to the present embodiment, mercury-resistant iron-oxidizing bacteria-containing water containing an inorganic carbon source and oxygen-containing fine bubbles is supplied to the contaminated soil or contaminated water 2. In an aerobic and inorganic carbon source-rich environment, the oxidation of iron, carbon fixation and reduction of mercury by mercury-resistant iron-oxidizing bacteria are promoted, and the purification of contaminated soil or contaminated water is promoted.

また、気化した水銀を含む水銀含有水が回収井戸４４を介して回収槽４１へと回収され、その後気液分離および水銀除去処理を経て水銀を含まない処理ガスのみが大気中に放出し、また、気液分離後の処理水が混合槽２２および混和槽２８へと返送されることから、原位置浄化装置１００からの有害な廃ガスおよび廃液を生じることが無く、環境への悪影響が実質的にない。 Further, the mercury-containing water containing vaporized mercury is recovered to the recovery tank 41 via the recovery well 44, and then through gas-liquid separation and mercury removal treatment, only the mercury-free processing gas is released into the atmosphere. Since the treated water after gas-liquid separation is returned to the mixing tank 22 and the mixing tank 28, no harmful waste gas and liquid are generated from the in-situ purification device 100, and the adverse effect on the environment is substantial. Not in.

そのうえ、原位置浄化装置１００は連続式で稼働可能であるから、大きな処理量に対応することができる。 Moreover, since the in-situ purification device 100 can be operated continuously, it can handle a large amount of processing.

さらに、ＣＯ２の供給量を調整することで、汚染土壌または汚染水２の環境を好気的に維持しつつ鉄源中の鉄の３価の酸化鉄への酸化を最小限に留めることが可能となる。 Furthermore, by adjusting the supply of CO 2 , it is possible to maintain the environment of contaminated soil or contaminated water 2 aerobicly while minimizing the oxidation of iron in the iron source to trivalent iron oxide. It will be possible.

２ 汚染土壌または汚染水
１０、１００ 汚染土壌または汚染水の原位置浄化装置
２２ 混合槽（供給手段）
２４ 送液手段（供給手段）
４１ 回収槽（回収手段）
４２ 吸引手段（回収手段） 2 Contaminated soil or contaminated water 10,100 In-situ purification device for contaminated soil or contaminated water 22 Mixing tank (supply means)
24 Liquid feeding means (supply means)
41 Collection tank (collection means)
42 Suction means (collection means)

Claims (7)

水銀化合物および／または水銀イオンで汚染された汚染土壌または汚染水を原位置で浄化する方法であって、
水銀耐性鉄酸化細菌、３価未満の酸化数の鉄を含む鉄源、無機炭素源および酸素含有微細気泡を含む水銀耐性鉄酸化細菌含有水を前記汚染土壌または汚染水に供給する水銀耐性鉄酸化細菌含有水供給工程を含むことを特徴とする汚染土壌または汚染水の原位置浄化方法。 A method of in-situ purification of contaminated soil or water contaminated with mercury compounds and / or mercury ions.
Mercury-resistant iron-oxidizing bacteria Mercury-resistant iron oxidation that supplies water containing mercury-resistant iron-oxidizing bacteria containing iron sources containing iron with an oxidation number of less than trivalent, inorganic carbon sources, and oxygen-containing microbubbles to the contaminated soil or contaminated water. A method for in-situ purification of contaminated soil or water comprising a bacterial-containing water supply step. 前記微細気泡含有水供給工程後、汚染土壌または汚染水中から還元気化された水銀を含む水銀含有水を回収する回収工程をさらに含む、請求項１に記載の汚染土壌または汚染水の原位置浄化方法。 The in-situ purification method for contaminated soil or contaminated water according to claim 1, further comprising a recovery step for recovering mercury-containing water containing reduced vaporized mercury from the contaminated soil or contaminated water after the fine bubble-containing water supply step. .. 前記酸素含有微細気泡が、発生時の直径が５０μｍ以下のマイクロバブルである、請求項１または２に記載の汚染土壌または汚染水の原位置浄化方法。 The method for in-situ purification of contaminated soil or contaminated water according to claim 1 or 2, wherein the oxygen-containing microbubbles are microbubbles having a diameter of 50 μm or less at the time of generation. 前記３価未満の酸化数の鉄を含む鉄源が硫酸第一鉄である、請求項１〜３の何れか一項に記載の汚染土壌または汚染水の原位置浄化方法。 The method for in-situ purification of contaminated soil or contaminated water according to any one of claims 1 to 3, wherein the iron source containing iron having an oxidation number of less than trivalent is ferrous sulfate. 前記無機炭素源が二酸化炭素であり、前記酸素含有微細気泡中の酸素が大気に含まれる酸素である、請求項１〜４の何れか一項に記載の汚染土壌または汚染水の原位置浄化方法。 The method for in-situ purification of contaminated soil or contaminated water according to any one of claims 1 to 4, wherein the inorganic carbon source is carbon dioxide, and the oxygen in the oxygen-containing microbubbles is oxygen contained in the atmosphere. .. 微細気泡含有水供給工程における無機炭素源の添加量が、前記汚染土壌または汚染水の酸化還元電位が−６００ｍＶ以上８００ｍＶ未満となるように調整される、請求項１〜４の何れか一項に記載の汚染土壌または汚染水の原位置浄化方法。 The amount of the inorganic carbon source added in the process of supplying water containing fine bubbles is adjusted so that the oxidation-reduction potential of the contaminated soil or contaminated water is -600 mV or more and less than 800 mV, according to any one of claims 1 to 4. The described method of in-situ purification of contaminated soil or contaminated water. 水銀化合物および／または水銀イオンで汚染された汚染土壌または汚染水を原位置で浄化する汚染土壌または汚染水の原位置浄化装置であって、
水銀耐性鉄酸化細菌、３価未満の酸化数の鉄を含む鉄源、無機炭素源および酸素含有微細気泡を含む微細気泡含有水を前記汚染土壌または汚染水に供給する供給手段と、
前記微細気泡含有水が供給された汚染土壌または汚染水中から還元気化された水銀を含む水銀含有水を回収する回収手段と、
を有することを特徴とする汚染土壌または汚染水の原位置浄化装置。 An in-situ purification device for in-situ purifying contaminated soil or contaminated water contaminated with mercury compounds and / or mercury ions.
Mercury-resistant iron-oxidizing bacteria, an iron source containing iron having an oxidation number of less than trivalent, an inorganic carbon source, and a supply means for supplying fine bubble-containing water containing oxygen-containing fine bubbles to the contaminated soil or contaminated water.
A recovery means for recovering mercury-containing water containing reduced vaporized mercury from the contaminated soil or contaminated water to which the fine bubble-containing water is supplied.
An in-situ purification device for contaminated soil or water characterized by having.
JP2018079154A 2018-04-17 2018-04-17 In-situ purification method and in-situ purification device for contaminated soil or water Active JP6968023B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2018079154A JP6968023B2 (en) 2018-04-17 2018-04-17 In-situ purification method and in-situ purification device for contaminated soil or water

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2018079154A JP6968023B2 (en) 2018-04-17 2018-04-17 In-situ purification method and in-situ purification device for contaminated soil or water

Publications (2)

Publication Number Publication Date
JP2019181411A JP2019181411A (en) 2019-10-24
JP6968023B2 true JP6968023B2 (en) 2021-11-17

Family

ID=68338750

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2018079154A Active JP6968023B2 (en) 2018-04-17 2018-04-17 In-situ purification method and in-situ purification device for contaminated soil or water

Country Status (1)

Country Link
JP (1) JP6968023B2 (en)

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0744982A1 (en) * 1994-02-16 1996-12-04 British Nuclear Fuels PLC Process for the treatment of contaminated material
JP3136458B2 (en) * 1994-08-24 2001-02-19 新日本製鐵株式会社 How to grow iron-oxidizing bacteria
JPH08216696A (en) * 1995-02-13 1996-08-27 Inoac Corp Window glass sealing member for vehicle and its manufacture
JP4578597B2 (en) * 1999-10-01 2010-11-10 株式会社間組 Mercury vaporization method, contaminated soil or contaminated water purification method, and mercury detection method
JP5846871B2 (en) * 2011-11-18 2016-01-20 Ｄｏｗａテクノロジー株式会社 Iron oxidation method and iron oxidation apparatus
JP6357360B2 (en) * 2014-06-18 2018-07-11 株式会社安藤・間 Electric culture device
JP5971606B1 (en) * 2015-12-18 2016-08-17 強化土株式会社 Soil purification method

Also Published As

Publication number Publication date
JP2019181411A (en) 2019-10-24

Similar Documents

Publication Publication Date Title
Wagner-Döbler Pilot plant for bioremediation of mercury-containing industrial wastewater
Zouboulis et al. Recent advances in the bioremediation of arsenic-contaminated groundwaters
Katsoyiannis et al. Use of iron-and manganese-oxidizing bacteria for the combined removal of iron, manganese and arsenic from contaminated groundwater
Corsini et al. Arsenic transforming abilities of groundwater bacteria and the combined use of Aliihoeflea sp. strain 2WW and goethite in metalloid removal
Li et al. Simultaneous arsenite and nitrate removal from simulated groundwater based on pyrrhotite autotrophic denitrification
Ruangchainikom et al. Characteristics of nitrate reduction by zero-valent iron powder in the recirculated and CO2-bubbled system
CA3040696C (en) Treatment of hydrogen sulfide gas under aerobic conditions
González-Pérez et al. Jet electro-absorbers for the treatment of gaseous perchloroethylene wastes
US7850854B2 (en) Method for perchlorate removal and destruction
JP6968023B2 (en) In-situ purification method and in-situ purification device for contaminated soil or water
JP2007160257A (en) Treatment method of harmful substance and treatment apparatus of harmful substance
JP4167052B2 (en) Purification method for organic compound contamination
JP5186169B2 (en) Purification method of soil and groundwater in aquifer
CN104310593B (en) A kind of method of thallium in cave effluent of carrying out a biological disposal upon
KR100228993B1 (en) Method for the remediation of polluted soils
US8734653B1 (en) Mercury remediation method and apparatus
Zhang et al. Synergetic degradation of Fe/Cu/C for groundwater polluted by trichloroethylene
Lee et al. A study on the application of manganese oxidizing bacteria for manganese treatment in acid mine drainage
JP5779115B2 (en) Cyanide purification method
Serna CHEMICAL OXIDATION AND IN-SITU BIOREMEDIATION OF CHLORINATED ETHENES
JPS60209294A (en) Manufacture of muroo volcanic rock containing abundant mineral relating to drinking water
CN106430431A (en) Iron-carbon micro-electrolysis method for treating wastewater containing inorganic and organic matter
Elkouz Treatment of Perchlorate and Multiple Oxyanions: Chemical and Biological Investigations
Duhl Microbially-mediated Transformations of Chlorinated Solvents and Engineered Nanomaterials in the Subsurface: Implications for Bioremediation, Natural Attenuation, Fate and Transport
Dutta et al. Ammonia recovery from salty liquids (ammonium solution, urea, etc.)

Legal Events

Date Code Title Description
A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20180420

A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20210204

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20210929

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20211019

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20211026

R150 Certificate of patent or registration of utility model

Ref document number: 6968023

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150

S531 Written request for registration of change of domicile

Free format text: JAPANESE INTERMEDIATE CODE: R313531

R350 Written notification of registration of transfer

Free format text: JAPANESE INTERMEDIATE CODE: R350