JP2004025172A

JP2004025172A - Method of purifying contaminated soil

Info

Publication number: JP2004025172A
Application number: JP2003125256A
Authority: JP
Inventors: Takeshi Kanzaki; 神前　健; Kiwamu Shiiba; 椎葉　究; Noriko Komine; 小峰　法子
Original assignee: Nisshin Seifun Group Inc
Current assignee: Nisshin Seifun Group Inc
Priority date: 2002-05-09
Filing date: 2003-04-30
Publication date: 2004-01-29
Anticipated expiration: 2023-04-30
Also published as: JP4067447B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of simply and rapidly purifying a soil contaminated by an organic contaminant such as a hydrocarbon based compound and an organic halogen compound while preventing an abnormal propagation of a microorganism preferably assimilating a low molecular weight nitrogen-containing substance and generation of a bad odor, and a purifying material therefor. <P>SOLUTION: Purification is carried out by adding at least one kind of purifying material selected from the group consisting of a purifying material (a) containing a wheat bran and/or a powder and a purifying material (b) containing a microorganism material containing a wheat bran and/or a powder and an aerobic microorganism to the soil contaminated by the organic contaminant; or adding at least one kind of compound selected from acetic acid, lactic acid and methanol with the above purifying material. The purifying material further contains the purifying material containing the wheat bran and/or the powder; the purifying material containing the microorganism material containing the wheat bran and/or the powder and the aerobic microorganism; or at least one kind of compound selected from acetic acid, lactic acid and methanol in the above purifying material. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、有機汚染物質で汚染された土壌の浄化方法、浄化用資材および浄化材に関する。より詳細には、本発明は、炭化水素系化合物や有機ハロゲン化合物などの有機汚染物質で汚染された土壌を、簡単に且つ速やかに浄化する方法並びにそのための浄化用資材および浄化材に関する。
【０００２】
【従来の技術】
炭化水素系化合物などの有機汚染物質で汚染された土壌から有機汚染物質を除去する方法として、従来、物理的処理法（例えば焼却やブロアーなどによる強制通気などによる方法）、化学的処理法（例えば界面活性剤などによる洗浄、還元鉄などの還元剤の添加などによる方法）、生物的処理法（有機汚染物質の微生物分解による方法）が開発されてきた。それらの処理法のうち、生物的処理法は、低コスト、簡便性、省エネルギーなどの点で優れていることから、バイオレメディエーション技術として注目され、技術開発が進んでいる。バイオレメディエーション技術としては、（１）土着微生物の栄養となる有機物を添加したり水分や通気量を加減して微生物活性を高めて汚染物質を分解する方法（バイオスティムレーション）、（２）汚染物質を分解する微生物を添加して分解する方法（バイオオーグメンテーション）、（３）前記（１）と（２）の方法を組み合わせた方法などが開発されてきた。
【０００３】
上記した（１）〜（３）に該当する従来法としては、（ｉ）汚染土壌を掘り起こして有機廃棄物および水分調整材を混合し、それを閉鎖状態でブロアーにより酸素を強制的に供給して土壌中の有機汚染物質を分解した後、混合物を篩分けして浄化した土壌から水分調整材を分離し、それにより得られる浄化土壌を土壌を掘り起こした箇所に復土する方法（特許文献１を参照）、（ｉｉ）有機塩素化合物で汚染された土壌を、還元雰囲気状態で且つ中性条件で、従属栄養型嫌気性微生物と金属鉄の存在下で、場合により有機系コンポストまたは堆肥化有機物を加えて脱塩素して浄化する方法（特許文献２を参照）、（ｉｉｉ）炭化水素系化合物などの有機汚染物質で汚染された土壌に、発酵を終了した堆肥および／または未発酵の有機物質を添加して浄化する方法（特許文献３〜５を参照）、（ｉｖ）多環芳香族炭化水素で汚染された土壌に、草、栽培植物を用いて動物糞を発酵させた堆肥におがくずと米ぬかを加えて二次発酵させて得られた発酵物などを加えて浄化する方法（非特許文献１を参照）が知られている。
【０００４】
しかしながら、上記（ｉ）の従来法は、汚染土壌に空気を吹き込むためのブロアー装置や、ブロアー処理によって土壌から空気中に揮散する汚染物質が周囲に拡散するのを防止するための閉鎖系施設を用いる必要があるため、装置が大規模になり経済的でない。その上、浄化処理を空気を吹き込みながら好気的条件で行うために、嫌気的条件下で分解され易い汚染物質の分解が行われにくく、汚染物質を完全に分解することが困難である。
【０００５】
また、上記（ｉｉ）の従来法は、従属栄養型嫌気性微生物を増殖させるための特定の培地（例えばメタン生成微生物用培地）を用いる必要があるためコストがかかる。しかも、コンポストなどに含まれている分子量５０００以下の低分子量窒素含有物質を好んで資化する微生物が異常に繁殖して、有機塩素化合物を資化する微生物の死滅や増殖阻害を生じ易く、そのため汚染物質の分解が速やかに行われにくく、しかも悪臭を発生する場合がある。
【０００６】
上記（ｉｉｉ）の従来法による場合も、上記（ｉｉ）の従来法と同様に、未完熟堆肥や発酵前の有機物質が分子量５０００以下の低分子量窒素含有物質を多く含んでいるために、該低分子量窒素含有物質を好んで資化する微生物が異常に繁殖して、炭化水素系化合物を資化する微生物の死滅や増殖阻害を生じ易く、汚染物質の分解が速やかに行われにくく、しかも悪臭を発生し易いという欠点がある。
【０００７】
また、上記（ｉｖ）の従来法は、汚染土壌に添加される二次発酵物がおがくずなどの木質材料を用いて製造されていることにより、該二次発酵物は低分子量窒素含有物質の含有量が少ないために低分子量窒素含有物質を好んで資化する微生物の異常繁殖が抑制でき、悪臭の発生が少ないという長所がある。しかしながら、汚染土壌中に雑菌や木質以外の有機物が多く含まれる場合は、汚染物質の分解が行われにくい。しかも、汚染土壌を浄化するための浄化用資材として、特定の発酵原料を用いて特定の方法で発酵させた発酵物（二次発酵物）を使用する必要があり、共通性および汎用性に乏しい。
【０００８】
【特許文献１】
特開平７−１００４５９号公報
【特許文献２】
特開平１０−２１６６９４号公報
【特許文献３】
特開平１１−４７７２７号公報
【特許文献４】
特開２０００−２５４６３５号公報
【特許文献５】
特表２００１−５０４０２９号公報
【非特許文献１】
「大林組技術研究所報」　２００１年、第６３巻、ｐ８１〜８４
【０００９】
【発明が解決しようとする課題】
本発明の目的は、炭化水素系化合物や有機ハロゲン化合物などの有機汚染物質で汚染された土壌を、簡単に且つ速やかに浄化することのできる浄化方法並びにそのための浄化用資材および浄化材を提供することである。
そして、本発明の目的は、浄化処理時に、分子量５０００以下の低分子量窒素含有物質を好んで資化する微生物の異常繁殖や悪臭の発生を防止しながら、炭化水素系化合物や有機ハロゲン化合物などの有機汚染物質で汚染された土壌を、円滑に且つ速やかに浄化する方法並びにそのための浄化用資材および浄化材を提供することである。
さらに、本発明の目的は、ブロアーなどの空気吹き込み装置や、閉鎖系施設などのコストのかかる特別の装置や施設を使用しなくても、炭化水素系化合物や有機ハロゲン化合物などの有機汚染物質で汚染された土壌を簡単に且つ低コストで浄化することのできる方法並びにそのための浄化用資材および浄化材を提供することである。
【００１０】
【課題を解決するための手段】
本発明者らは上記の目的を達成すべく検討を重ねてきた。その結果、炭化水素系化合物や有機ハロゲン化合物などの有機汚染物質で汚染された土壌に、小麦フスマおよび末粉の少なくとも一方を含有する浄化用資材、および小麦フスマおよび末粉の少なくとも一方に好気性微生物を含む微生物資材を加えた浄化用資材から選ばれる少なくとも１種の浄化用資材を添加して浄化処理を行うと、ブロアー装置や閉鎖系施設などの特定の装置や施設を使用することなく、低分子量窒素含有物質を好んで資化する微生物の異常繁殖や悪臭の発生を防止しながら、土壌中に含まれている炭化水素系化合物や有機ハロゲン化合物などの有機汚染物質の分解が促進されて、土壌の浄化が円滑に行われることを見出した。
また、本発明者らは、その際に小麦フスマおよび末粉の少なくとも一方の含有量が０．５質量％以上である浄化用資材を用いることが、浄化の促進、低分子量窒素含有物質を好んで資化する微生物の異常繁殖や悪臭の発生の防止により効果があることを見出した。
【００１１】
さらに、本発明者らは、汚染土壌の浄化時に、小麦フスマおよび末粉の少なくとも一方を含有する浄化用資材、および小麦フスマおよび末粉の少なくとも一方に好気性微生物を含む微生物資材を加えてなる浄化用資材から選ばれる少なくとも１種の浄化用資材と共に、酢酸、乳酸およびメタノールから選ばれる少なくとも１種の化合物を添加すると、土壌中に含まれて炭化水素系化合物や有機ハロゲン化合物などの有機汚染物質の分解が一層促進されて、有機汚染物質で汚染された土壌を速やかに、短期間に浄化できることを見出した。
また、本発明者らは、小麦フスマおよび末粉の少なくとも一方を含有する浄化用資材、および／または小麦フスマおよび末粉の少なくとも一方に好気性微生物を含む微生物資材を加えてなる浄化用資材中に、分子量５０００以下の低分子量窒素含有物質の含有量の少ない、完熟堆肥、消化汚泥および腐植酸などの他の成分を含有させておくことが、浄化を促進するために好ましいことを見出した。
また、本発明者らは、炭化水素系化合物や有機ハロゲン化合物などの有機汚染物質で汚染された土壌１００質量部に対して、前記した浄化用資材を０．１〜２０質量部の割合で添加することが浄化促進などの点から望ましいことなどを見出し、それらの種々の知見に基づいて本発明を完成した。
【００１２】
すなわち、本発明は、
（１）　有機汚染物質で汚染された土壌に、
（ａ）小麦フスマおよび末粉の少なくとも一方を含有する浄化用資材；および、（ｂ）小麦フスマおよび末粉の少なくとも一方に、好気性微生物を含む微生物資材を加えた浄化用資材；
から選ばれる少なくとも１種の浄化用資材を添加して浄化を行うことを特徴とする有機汚染物質で汚染された土壌の浄化方法である。
さらに、本発明は、
（２）　有機汚染物質で汚染された土壌に、
（ａ）小麦フスマおよび末粉の少なくとも一方を含有する浄化用資材；および、（ｂ）小麦フスマおよび末粉の少なくとも一方に、好気性微生物を含む微生物資材を加えた浄化用資材；
から選ばれる少なくとも１種の浄化用資材を添加すると共に、酢酸、乳酸およびメタノールから選ばれる少なくとも１種の化合物を添加して浄化を行うことを特徴とする有機汚染物質で汚染された土壌の浄化方法である。
【００１３】
そして、本発明は、
（３）　浄化用資材（ａ）および浄化用資材（ｂ）が、小麦フスマおよび末粉の少なくとも一方を、浄化用資材（ａ）または浄化用資材（ｂ）の質量に対して５質量％以上の割合で含有する前記（１）または（２）の浄化方法；
（４）　浄化用資材（ａ）が小麦フスマおよび末粉の少なくとも一方と共に完熟堆肥、消化汚泥および腐植酸の少なくとも１種を含有し、浄化用資材（ｂ）が小麦フスマおよび末粉の少なくとも一方並びに好気性微生物を含む微生物資材と共に完熟堆肥、消化汚泥および腐植酸の少なくとも１種を含有する前記（１）〜（３）のいずれかの浄化方法；
（５）　有機汚染物質で汚染された土壌１００質量部に対して浄化用資材（ａ）および浄化用資材（ｂ）から選ばれる少なくとも１種の浄化用資材を０．１〜２０質量部の割合で添加する前記（１）〜（４）のいずれかの浄化方法；
（６）　土壌と、浄化用資材（ａ）および浄化用資材（ｂ）から選ばれる少なくとも１種の浄化用資材の合計質量に対して、酢酸、乳酸およびメタノールから選ばれる少なくとも１種の化合物を１０ｐｐｍ以上の量で添加する前記（２）〜（５）のいずれかの浄化方法；および、
（７）　有機汚染物質で汚染された土壌が、炭化水素系化合物および／または有機ハロゲン化合物で汚染された土壌である前記（１）〜（６）のいずれかの浄化方法；
である。
【００１４】
また、本発明は、
（８）　（ａ）小麦フスマおよび末粉の少なくとも一方を含有するか、或いは（ｂ）小麦フスマおよび末粉の少なくとも一方と共に好気性微生物を含む微生物資材を含有する、ことを特徴とする有機汚染物質で汚染された土壌を浄化するための浄化用資材である。
そして、本発明は、
（９）　小麦フスマおよび末粉の少なくとも一方を浄化用資材の質量に対して０．５質量％以上の割合で含有する前記（８）の浄化用資材；
（１０）　小麦フスマおよび末粉の少なくとも一方と共に完熟堆肥、消化汚泥および腐植酸の少なくとも１種を含有するか、或いは小麦フスマおよびふすまの少なくとも一方並びに好気性微生物を含む微生物資材と共に完熟堆肥、消化汚泥および腐植酸の少なくとも１種を含有する前記（８）または（９）の浄化用資材；および、
（１１）　炭化水素系化合物および／または有機ハロゲン化合物で汚染された土壌を浄化するための浄化用資材である前記（８）〜（１０）のいずれかの浄化用資材；
である。
【００１５】
さらに、本発明は、
（１２）　前記（８）〜（１１）のいずれかの浄化用資材に、浄化用資材の質量に対して酢酸、乳酸およびメタノールから選ばれる少なくとも１種の化合物を６０ｐｐｍ以上の量で添加したことを特徴とする有機汚染物質で汚染された土壌を浄化するための浄化材である。
【００１６】
【発明の実施の形態】
以下に本発明について詳細に説明する。
本発明の浄化方法、浄化用資材および浄化材は、有機汚染物質で汚染された土壌のいずれに対しても適用でき、そのうちでも炭化水素系化合物および／または有機ハロゲン化合物で汚染された土壌の浄化に適している。
本発明の浄化方法および浄化材で浄化する炭化水素系化合物および／または有機ハロゲン化合物で汚染された土壌としては、例えば、原油、重油、軽油、灯油などの油類、機械加工や装置類などに用いられる潤滑油、切削油、電子機械金属部品の脱脂、洗浄、ドライクリーニングなどに用いられ有機塩素化合物などで汚染された土壌を挙げることができる。
前記した汚染土壌には、有機汚染物質の種類に応じて、例えば、パラフィン系やオレフィン系の脂肪族炭化水素化合物、ベンゼン、トルエン、キシレン、エチルベンゼンなどの単環式芳香族炭化水素、フェナントレン、アントラセン、ベンゾアントラセン、フルオランテン、ピレン、クリセン、ベンゾフルオランテン、ベンゾピレンなどの多環式芳香族炭化水素、ジクロロエチレン、トリクロロエチレン、テトラクロロエチレン、ジクロロエタン、トリクロロエタン、テトラクロロエタン、クロルダン、ジエルドリン、トキサフェン、アルドリン、エントリン、ヘプタクロルエポキシド、メトキシクロル、ベンゼンヘキサクロリドなどの有機塩素化合物などの汚染化合物の１種または２種以上が含まれている。
そのうちでも、本発明の浄化方法および浄化材は、共有二重結合を持つ有機塩素系化合物で汚染された土壌を浄化するのに適している。
【００１７】
浄化対象である汚染土壌中での有機汚染物質の濃度は特に制限されないが、土壌中での有機汚染物質の濃度が高すぎると有機汚染物質の分解が円滑に進行しにくくなり、浄化に時間がかかるようになる。かかる点から、本発明の浄化方法、浄化用資材および浄化材は、有機汚染物質の濃度が土壌１ｋｇ中１０ｇ以下（１００００ｐｐｍ以下）である汚染土壌の浄化に適している。土壌中の有機汚染物質の濃度が前記１００ｐｐｍ以下の場合には、本発明の浄化方法、浄化用資材および浄化材によって、土壌中に含まれる有機汚染物質が短期間で完全にまたはほぼ完全に分解されて、良好な浄化結果を速やかに達成することができる。
【００１８】
本発明の浄化方法では、汚染土壌における水分含量は、土壌の種類、土壌中に含まれる有機汚染物質の種類や濃度、土壌中に含まれる他の成分の種類や濃度などに応じて異なり得るが、一般には、汚染土壌の水分含量が３０〜９０質量％、特に５０〜７０質量％の範囲内であるときに、有機汚染物質の分解がより促進されて、良好な浄化結果を速やかに達成することができる。そのため、汚染土壌の水分含量が３０質量％よりも低い場合は土壌に加水し、また汚染土壌の水分含量が９０質量％よりも高い場合は土壌を乾燥して、汚染土壌の水分含量を３０〜９０質量％に調整して本発明の浄化処理を行うことが好ましい。
【００１９】
本発明では、炭化水素系化合物や有機ハロゲン化合物などの有機汚染物質で汚染された土壌の浄化に当たって、浄化用資材として、（ａ）小麦フスマおよび末粉の少なくとも一方を含有する浄化用資材［「浄化用資材（ａ）」ということがある］；および（ｂ）小麦フスマおよび末粉の少なくとも一方に好気性微生物を含む微生物資材を加えた浄化用資材［浄化用資材（ｂ）」ということがある］から選ばれる少なくとも１種の浄化用資材を用いる。
浄化用資材（ａ）および浄化用資材（ｂ）は、いずれも、浄化用資材の質量に対して、小麦フスマおよび末粉の少なくとも一方を０．５質量％以上（小麦フスマと末粉の両方を含有する場合は両者の合計質量；以下同様）の割合で含有することが好ましく、２質量％以上の割合で含有することがより好ましく、５〜１００質量％の割合で含有することが更に好ましい。
浄化用資材（ａ）および浄化用資材（ｂ）における小麦フスマおよび末粉の少なくとも一方の含有量が０．５質量％未満であると、炭化水素系化合物や有機ハロゲン化合物などの有機汚染物質で汚染された土壌を短期間に浄化しにくくなる［以下浄化用資材（ａ）および浄化用資材（ｂ）を総称して単に浄化用資材ということがある］。
【００２０】
本発明で用いる小麦フスマは、周知のように小麦粒の外皮であり、また末粉（すえこ）は小麦粒外皮に付着する胚乳部（小麦粉）と小麦フスマを含む粉状物であり、いずれも小麦製粉時の副産物として得られる。
小麦フスマおよび／または末粉が、炭化水素系化合物や有機ハロゲン化合物などの有機汚染物質を含有する土壌の浄化促進作用を有する理由は明確ではないが次のように推測される。
すなわち、小麦フスマおよび末粉は、ヘミセルロース成分を高含量（３５質量％程度）で含んでおり、該ヘミセルロースはアラビノース側鎖を多く有するアラビノキシランを含んでいる。また、小麦粉および末粉は、Ｃ／Ｎ比が１５付近であり且つ含水率が低く（１５重量％以下）且つ土壌中で酸素の存在する空隙をつくりやすい形状をしている。そのため、小麦フスマおよび末粉を含有する浄化用資材を有機汚染物質で汚染された土壌に添加すると、アラビノキシランを分解できる微生物が土壌中で選択的に増殖され、該微生物が炭化水素系化合物や有機ハロゲン化合物などの有機汚染物質の分解を促進するものと推測される。
【００２１】
また、浄化用資材（ｂ）で用いる好気性微生物を含む微生物資材としては、小麦フスマおよび／または末粉を資化することができ且つ８０℃の温度で１０分間処理した後でも５５℃の温度で生存可能な好気性の耐熱性菌を含む資材が好ましく用いられる。そのような耐熱性菌の例としては、バチルス・サブチルス（Ｂａｃｉｌｌｕｓ　ｓｕｂｔｉｌｉｓ）、バチルス・コアギュランス（Ｂａｃｉｌｌｕｓ　ｃｏａｇｕｌａｎｓ）、バチルス・ステアロサーモフィラス（Ｂａｃｉｌｌｕｓ　ｓｔｅａｒｏｔｈｅｒｍｏｐｈｉｌｕｓ）などのバチルス属微生物、サーモアクチノミセス・ブルガリス（Ｔｈｅｒｍｏａｃｔｉｎｏｍｙｃｅｓ　ｖｕｌｇａｒｉｓ）、サーモモノスポーラ・カーバラ（Ｔｈｅｒｍｏｍｏｎｏｓｐｏｒａ　ｃｕｒｖａｒａ）などの好温・好熱性の放線菌、フミコーラ・インソレンス（Ｈｕｍｉｃｏｌａ　ｉｎｓｏｋｅｎｓ）、タラロマイセス・デユポンティ（Ｔａｌａｒｏｍｙｃｅｓ　ｄｕｐｏｎｔｉｉ）などの好熱性の糸状菌などを挙げることができる。本発明で用いる浄化用資材（ｂ）は、これらの耐熱性菌の１種または２種以上を含有することができる。前記した耐熱性菌は、微生物製剤等として市販されており、市販のものをそのまま用いてもよい。また、場合によっては、前記した耐熱性菌を培養増殖して用いてもよい。これらの耐熱性菌の多くは、小麦フスマまたは末粉を分解する能力が高く、且つ有機物を高温で分解する能力に優れている。好気性微生物を含む微生物資材を含有する浄化用資材（ｂ）では、上記浄化用資材（ｂ）１ｇ当たり、好気性微生物を１０^５ＣＦＵ（Ｃｏｌｏｎｙ　Ｆｏｒｍｉｎｇ　Ｕｎｉｔ）以上の割合で含有することが好ましい。
好気性微生物を含む微生物資材中に好気性微生物を活性化する活性剤を含有させておくと、好気性微生物の増殖が一層促進され、汚染土壌の浄化がより促進されるので好ましい。好気性微生物の活性剤としては、例えば、後記する腐植酸、浄化用資材（ｂ）のｐＨを好気性微生物の増殖に適したものに調整し得るアルカリなどのｐＨ調整剤などを挙げることができる。
【００２２】
本発明で用いる浄化促進剤（ａ）および／または浄化用資材（ｂ）は、小麦フスマ、末粉、好気性微生物を含む微生物資材以外に、必要に応じて他の成分を含有することができる。浄化促進剤中に含有させる他の成分としては、微生物により容易に分解される低分子量の窒素含有化合物（一般に分子量５０００以下の窒素含有化合物）の含有割合が１質量％以下である高分子量有機物が好ましく用いられる。該他の成分が低分子量の窒素含有化合物（一般に分子量５０００以下の窒素含有化合物）を多く含有していると、土壌の浄化時に、低分子量窒素含有物質を好んで資化する微生物の異常繁殖や悪臭の発生が生じ易くなり、好ましくない。
小麦フスマおよび末粉の少なくとも一方、好気性微生物を含む微生物資材と共に用い得る低分子量の窒素含有化合物の含有量の少ない他の成分としては、特に、完熟堆肥、消化汚泥および腐植酸の少なくとも１種が好ましく、浄化促進剤は前記した他の成分の１種または２種以上を含有することができる。
浄化用資材中に完熟堆肥、消化汚泥および腐植酸などの他の成分を含有させる場合は、該他の成分の含有量は、浄化用資材の質量に対して、９９．５質量％以下であることが好ましく、９８質量％以下であることがより好ましく、９５質量％であることが更に好ましい。
【００２３】
本発明において、浄化用資材中に含有させることのできる完熟堆肥としては、例えば、鶏、牛、豚、馬などの家畜類の糞尿、食品残渣（例えば食品の製造・加工場、卸売場などから排出される各種食品残渣、飲食店、ホテル、学校、家庭などから排出される各種食品残渣など）、植物発生材（例えば植物に由来する葉、茎、根、果実、実の外殻、木質系建築廃材など）、活性汚泥などの有機質材料を発酵原料として用いて微生物によって完全に分解させた堆肥を挙げることができる。
また、本発明において、浄化用資材中に含有させることのできる消化汚泥は、下水処理場などで発生する汚泥を消化槽により完全に分解することによって得られた汚泥である。
【００２４】
本発明において、浄化用資材中に含有させることのできる腐植酸としては、石炭化度の低い泥炭、亜炭などの若年炭類に含まれるアルカリ可溶の不定形高分子有機酸、および該不定形高分子有機酸を硝酸で酸化分解して得られるニトロフミン酸およびその塩類などが挙げられる。また、浄化用資材は、フミン酸の代わりに、泥炭、亜炭等の若年炭などのフミン酸を含有する物質を腐植酸として含有してもよい。そのうちでも、泥炭、亜炭などの若年炭類をそのまま使用せずに、それらから分離されたフミン酸や、ニトロフミン酸、またはその塩類を用いることが、少量の使用量で、炭化水素系化合物や有機ハロゲン化合物などの有機汚染物質の分解に有用な微生物の増殖を行うことができるので望ましい。
【００２５】
本発明で用いる浄化用資材のｐＨは、浄化用資材を添加する土壌の種類、土壌中に含まれる有機汚染物質の種類などに応じて異なり得るが、一般的には３〜８．５の範囲であることが好ましく、４〜７の範囲であることがより好ましい。浄化用資材のｐＨが３よりも低い場合および８．５よりも高い場合は、炭化水素系化合物や有機ハロゲン化合物などの有機汚染物質で汚染された土壌に添加したときに、有機汚染物質を分解する微生物が土壌中で増殖しにくくなり、土壌を短期間に浄化しにくくなる。
浄化用資材の元のｐＨや土壌のｐＨに応じて、アルカリおよび／または酸をｐＨ調整剤として用いて、浄化用資材のｐＨを前記した範囲にすることが好ましい。ｐＨの調整に用いるアルカリとしては、例えば、炭酸カルシウム；石灰や消石灰；アルカリ金属の水酸化物や炭酸塩；石炭、汚泥、家畜糞等の焼成灰などを用いることができ、また酸としては、種々の無機酸や有機酸を用いることができる。
【００２６】
汚染土壌に対する浄化用資材（ａ）および浄化用資材（ｂ）から選ばれる少なくとも１種の浄化用資材の添加量は、浄化用資材中の小麦フスマおよび末粉の少なくとも一方の含有量、好気性微生物を含む微生物資材の含有量、浄化用資材に含まれる前記以外の他の成分の種類や含有量、処理対象である土壌の種類、土壌に含まれる有機汚染物質の種類および濃度、土壌に含まれる他の成分の種類や濃度などに応じて異なり得るが、一般には、汚染土壌１００質量部に対して浄化用資材（ａ）および浄化用資材（ｂ）の少なくとも１種（複数の浄化用資材を用いる場合はその合計量）を０．１〜２０質量部、特に１〜５質量部の割合で添加することが、浄化処理時に有機汚染物質の分解が良好に行われ、分子量５０００以下の低分子量窒素含有物質を好んで資化する微生物の異常繁殖が防止され、悪臭の発生を防止でき、しかも混合作業が容易であることから好ましい。
汚染土壌１００質量部に対して浄化用資材の添加量が０．１質量部未満であると、有機汚染物質を分解する微生物が土壌中で増殖しにくくなり、汚染土壌の浄化に長い時間を要するようになり、一方２０質量部を超すと分子量５０００以下の低分子量窒素含有物質を好んで資化する微生物の異常繁殖、悪臭などが生じ易くなる。
【００２７】
本発明では、有機汚染物質で汚染された土壌に浄化用資材（ａ）および浄化用資材（ｂ）の少なくとも１種を添加して浄化を行うに当たって、浄化用資材（ａ）および浄化用資材（ｂ）の少なくとも１種と共に、更に酢酸、乳酸およびメタノールから選ばれる少なくとも１種の化合物を添加することが好ましい。酢酸、乳酸およびメタノールから選ばれる少なくとも１種の化合物を汚染土壌に更に添加することによって、短期間のうちに有機汚染物質を分解する微生物が土壌中で大幅に増殖されて、有害ガスの発生を抑えながら、土壌中の有機汚染物質が短期間で無害な物質へと分解されるようになり、土壌の浄化が速やかに行われるようになる。
汚染土壌の浄化に当たっては、浄化用資材（ａ）および浄化用資材（ｂ）の少なくとも１種と共に、酢酸、乳酸およびメタノールから選ばれる化合物のうちの１種のみを含有させてもよいし、２種を含有させてもよいし、または３種を含有させてもよい。
【００２８】
酢酸、乳酸およびメタノールから選ばれる少なくとも１種の化合物の添加量は、土壌の種類、土壌に含まれる有機汚染物質の種類や濃度、浄化用資材（ａ）および／または浄化用資材（ｂ）の内容などに応じて調整し得るが、一般的には汚染土壌および浄化用資材の合計質量に対して酢酸、乳酸およびメタノールから選ばれる少なくとも１種を１０ｐｐｍ以上の割合で添加することが好ましく、２０ｐｐｍ以上の割合で添加することがより好ましく、２０〜５０ｐｐｍの割合で添加することが更に好ましい。
酢酸、乳酸およびメタノールから選ばれる少なくとも１種の化合物の添加量が、汚染土壌および浄化促進剤の合計質量に対して１０ｐｐｍ未満であると、有機汚染物質を分解する微生物が土壌中で短期間に増殖されなくなったり、悪臭や有害ガスの発生を抑えながら土壌中の有機汚染物質を無害な物質へと速やかに分解することができなくなることがある。
一方、酢酸、乳酸およびメタノールから選ばれる少なくとも１種の化合物の添加量が、汚染土壌および浄化促進剤の合計質量に対して１００ｐｐｍを超えて高くなり過ぎると、微生物による有機汚染物質の分解活性を低下させることになり好ましくない。
【００２９】
汚染された土壌への、浄化用資材（ａ）および／または浄化用資材（ｂ）の添加方法、または浄化用資材（ａ）および／または浄化用資材（ｂ）と酢酸、乳酸およびメタノールから選ばれる少なくとも１種の化合物の添加方法は、特に制限されず、浄化用資材（ａ）および／または浄化促進剤（ｂ）や、酢酸、乳酸およびメタノールから選ばれる少なくとも１種の化合物が土壌中に均一に混合され得る方法であればいずれの方法で行ってもよい。
汚染土壌に浄化促進剤（ａ）および／または（ｂ）と共に酢酸、乳酸およびメタノールから選ばれる少なくとも１種の化合物を添加する場合は、浄化用資材（ａ）および／または浄化用資材（ｂ）と前記化合物を汚染土壌に同時に添加してよいし、逐次に添加してもよい。また、浄化促進剤（ａ）および浄化用資材（ｂ）の少なくとも１種に酢酸、乳酸およびメタノールから選ばれる少なくとも１種の化合物を予め混合しておき、その混合物を汚染土壌に添加してもよい。
浄化用資材に酢酸、乳酸およびメタノールから選ばれる少なくとも１種の化合物を予め混合しておく場合は、浄化用資材（ａ）および／または浄化用資材（ｂ）に対して酢酸、乳酸およびメタノールから選ばれる少なくとも１種の化合物を６０ｐｐｍ以上の割合で混合しておくことが好ましい。
【００３０】
小麦フスマおよび末粉の少なくとも一方と場合により更に他の成分（完熟堆肥、消化汚泥、腐植酸など）を含有する浄化用資材（ａ）或いは小麦フスマおよび末粉の少なくとも一方並びに好気性微生物を含む微生物資材と場合により更に他の成分（完熟堆肥、消化汚泥、腐植酸など）を含有する浄化用資材（ｂ）に、酢酸、乳酸およびメタノールから選ばれる少なくとも１種の化合物を混合してなる前記混合物は、いずれも、浄化促進剤または浄化材として独自に貯蔵、流通、販売が可能であり、したがって本発明はそのような浄化促進剤および浄化材を本発明の範囲に包含する。
本発明の上記した浄化促進剤および浄化材を、炭化水素系化合物や有機ハロゲン化合物などの有機汚染物質で汚染された土壌に添加することによって、極めて簡単な操作で、土壌の浄化を行うことができる。
【００３１】
炭化水素系化合物や有機ハロゲン化合物などの有機汚染物質で汚染された土壌に、浄化用資材（ａ）および浄化用資材（ｂ）の少なくとも１種を添加するか、または浄化用資材（ａ）および浄化用資材（ｂ）の少なくとも１種と共に酢酸、乳酸およびメタノールから選ばれる少なくとも１種の化合物を添加して浄化を行うに当たっては、浄化用資材（ａ）および／または浄化用資材（ｂ）を添加した汚染土壌混合物、または浄化用資材（ａ）および／または浄化用資材（ｂ）と共に酢酸、乳酸およびメタノールから選ばれる少なくとも１種の化合物を添加した汚染土壌混合物を、堆積状態にし、堆積物全体で有機汚染物質の分解が均一に行われるようにするために２カ月に１回〜２回程度の割合で撹拌や切り返しを行うことによって土壌の浄化を円滑に行うことができる。
浄化処理時の汚染土壌混合物のｐＨは一般に４〜９、特に５〜８であるのが、炭化水素系化合物や有機ハロゲン化合物などの有機汚染物質の分解が良好になり、浄化を短期間で行える点から好ましい。
【００３２】
浄化に要する期間は、汚染土壌中に含まれている有機汚染物質の種類や濃度、汚染土壌の水分含量、浄化時の温度などの条件に応じて異なるが、一般には、土壌中の有機汚染物質の濃度が環境基準以下（例えばトリクロロエチレンでは０．０３ｐｐｍ以下）になった時点で浄化が終了したとみなすことができる。
本発明の浄化方法または浄化材を採用して浄化した後の土壌は、土壌中の有機汚染物質がほぼ完全に分解除去されていて無毒化されているので、そのまま自然環境に戻すことができ、また園芸用土壌や他の用途に用いることもできる。
【００３３】
【実施例】
以下に実施例などにより本発明について具体的に説明するが、本発明は以下の例に何ら限定されるものではない。
【００３４】
《参考例１》［木質堆肥の製造］
森林伐採材の粉砕チップに水を加えて均一に混合して水分含量６０質量％に調整して堆積した。これを、１カ月ごとに撹拌、切り返しを行って発酵させ、６カ月後に発酵を終了して木質堆肥を製造した。
【００３５】
《参考例２》［消化汚泥の製造］
埼玉県の下水処理場で発生した消化汚泥に等質量の水道水を加えて十分に撹拌した後、３０００Ｇで１０分間遠心分離し、それにより得た沈殿物に等質量の水道水を加えて３０００Ｇで１０分間遠心分離して生成した沈殿物を回収するという洗浄処理を更に５回繰り返し、それにより得られた沈殿物を消化汚泥として用いた。
【００３６】
《実施例１》
（１）　小麦フスマと、上記の参考例１で調製した木質堆肥または参考例２で調製した消化汚泥を下記の表１に示す割合で混合して浄化用資材Ａ〜Ｇをそれぞれ調製した。
（２）　市販の黒土（水分含量５１．３質量％）２５０ｇに、上記（１）で調製したそれぞれの浄化用資材５ｇを添加し、さらに酢酸またはメタノールを下記の表２に示す量で混合して黒土混合物を調製した。黒土混合物のｐＨを測定したところ、下記の表２に示す通りであった。
また、対照として、浄化用資材、酢酸およびメタノールのいずれも添加しない黒土を準備し、そのｐＨを測定したところ、下記の表２に示す通りであった。
（３）　上記（２）で調製した黒土混合物および対照用の黒土をそれぞれのフラスコ（７６０ｍｌ容）に入れ、そこにトリクロロエチレン２．５ｍｇを添加し（トリクロロエチレンの濃度：黒土の質量に対して１０ｐｐｍ、黒土と浄化用資材の合計質量に対して９．８ｐｐｍ）、添加後にテフロン（デュポン社の登録商標）加工したブチルゴム栓をして、２５℃の恒温槽内に３週間静置した。その間、栓をしたままの状態で１週間に１回の割合で軽く撹拌した。
（４）　３週間後に黒土混合物および黒土（対照用）中のトリクロロエチレンの濃度を下記の方法で測定したところ下記の表２に示すとおりであった。
【００３７】
［浄化処理後の土壌中のトリクロロエチレン含有量（濃度）の測定］
上記３週間の試験後に、ブチルゴム栓付きの試験フラスコのヘッドスペース部の気体をシリンジで採取し、ＧＣ−ＭＳで該気体中のトリクロロエチレン濃度を分析し、気体中のトリクロロエチレン濃度をもって土壌中のトリクロロエチレン濃度と見做した（ヘッドスペース部の気体中のトリクロロエチレン濃度は土壌中のトリクロロエチレン濃度に比例する）。ＧＣ−ＭＳ分析の条件は、ＪＩＳ　Ｋ
０１２５（用水・廃水中の揮発性有機化合物試験方法）によった。
【００３８】
【表１】

【００３９】
【表２】

【００４０】
上記の表２の結果にみるように、実験番号１（対照例）では、トリクロロエチレンで汚染された土壌（黒土）に浄化用資材、酢酸およびメタノールのいずれも添加せずに浄化処理を行ったために、３週間後の土壌中のトリクロロエチレンの含有量は８．８ｐｐｍであり、浄化の程度が低いものであった。
これに対して、実験番号２〜６では、トリクロロエチレンで汚染された土壌に、小麦フスマを含有する浄化用資材を添加して浄化を行ったことにより、３週間後の土壌中のトリクロロエチレンの含有量が実験番号１に比べて大幅に低下しており、良好な浄化結果が得られた。
さらに、実験番号７〜１０では、トリクロロエチレンで汚染された土壌に、小麦フスマを含有する浄化用資材と共に酢酸またはメタノールを添加して浄化を行ったことにより、３週間後の土壌中のトリクロロエチレンの含有量が一層大きく低減しており、極めて良好な浄化結果が得られた。
【００４１】
《実施例２》
（１）　市販の黒土を１ｋｇずつ５区分準備し、それぞれにＡ重油１０ｇ（黒土の重量に対して外割で１質量％）を添加して、温度２５℃の室内に１カ月放置して重油汚染土壌をそれぞれ調製した。それぞれの重油汚染土壌中の油分濃度を以下の方法で測定したところ、下記の表４に示すように２５００ｐｐｍ前後であった。
【００４２】
［土壌中の重油濃度の測定］
試料土壌５ｇに対して、スポイトで１Ｎ塩酸３滴を滴下すると共に飽和食塩水５ｍｌおよび抽出溶媒（トリクロロトリフルオロエチレン）１０ｍｌを加えて、室温（２５℃）で５時間にわたって振とう処理を行い、土壌中の油分（重油）をトリクロロトリフルオロエチレン中に抽出した。抽出後、トリクロロトリフルオロエチレン層を分取し、そこに含まれる油分（重油）の濃度を油分濃度計（株式会社堀場製作所製「ＯＣＭＡ−３５０」）を使用して測定し、その油分濃度から、試料土壌中に含まれていた重油の濃度を求めた。
【００４３】
（２）　小麦フスマ、腐植酸（株式会社テルナイト製「ＨＡ−０１」）、石灰質肥料（村樫石灰工業株式会社製「くみあい炭酸カルシウム肥料」；ｐＨ調整用）および好気性微生物資材（日清製粉株式会社製「アクセルコンポ」）を用いて、下記の表３に示す浄化用資材ａ〜ｃをそれぞれ調製した。
（３）　上記（１）で調製したそれぞれの重油汚染土壌１０００ｇに対して、上記（２）で調製した浄化用資材ａ〜ｃのそれぞれを下記の表４に示す量で添加し、それぞれを小型発酵リアクターに充填して、外気温度２０℃で、１４日間静置した（発酵リアクター内の土壌温度：約２５〜３０℃）。１４日後に、土壌を発酵リアクターから取り出して、土壌中の油分（重油）濃度を上記した方法で測定し、その測定値から油分（重油）濃度の減少率を求めたところ、下記の表４に示すとおりであった。
（４）　また、対照として、浄化用資材を添加せずに、上記（１）で調製した重油汚染土壌をそのまま小型発酵リアクターに充填して、上記（３）と同様にして１４日間静置し、１４日後に発酵リアクターから土壌を取り出して、土壌中の油分（重油）濃度を上記した方法で測定し、その測定値から油分（重油）濃度の減少率を求めたところ、下記の表４に示すとおりであった。
【００４４】
【表３】

【００４５】
【表４】

【００４６】
上記の表４の結果にみるように、実験番号１２（対照例）では、重油で汚染された土壌（黒土）に浄化用資材を添加せずに浄化処理を行ったために、１４日後の土壌の油分（重油）濃度の減少率は８．７％と低いものであった。
それに対して、実験番号１３〜１６では、重油で汚染された土壌に、小麦フスマを含有する浄化用資材を添加して浄化を行ったことにより、１４日後の土壌中の重油濃度が実験番号１２に比べて大幅に低下していて、油分濃度の減少率がいずれも５０％を超えていて、良好な浄化結果が得られた。
特に、小麦フスマと共に腐植酸および好気性微生物資材を含有する浄化用資材ｃを重油汚染土壌に添加した実験番号１６では、油分濃度の減少率が極めて高く、非常に良好な浄化結果が得られた。
【００４７】
【発明の効果】
本発明による場合は、土壌中に含まれる炭化水素系化合物や有機ハロゲン化合物などの有機汚染物質の分解が従来よりも促進されて、該有機汚染物質で汚染された土壌を短期間で円滑に浄化することができる。
また、本発明による場合は、炭化水素系化合物や有機ハロゲン化合物などの有機汚染物質で汚染された土壌の浄化の際に、低分子量窒素含有物質を好んで資化する微生物の異常繁殖や悪臭の発生を防止しながら、前記汚染土壌を短期間で円滑に浄化することができる。
さらに、本発明による場合は、ブロアー装置や閉鎖系施設などの特定の装置や施設を使用することなく、有機汚染物質で汚染された土壌を、簡単に、速やかに且つ低コストで浄化することができる。
本発明において、炭化水素系化合物や有機ハロゲン化合物などの有機汚染物質で汚染された土壌に、小麦フスマおよび末粉の少なくとも一方を含有する浄化用資材（ａ）並びに小麦フスマおよび末粉の少なくとも一方と好気性微生物を含む微生物資材を含有する浄化用資材（ｂ）から選ばれる少なくとも１種と共に、酢酸、乳酸およびメタノールから選ばれる少なくとも１種の化合物を添加して浄化を行う場合に、土壌の有機汚染物質が一層短期間に分解され、極めて良好な浄化結果を得ることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for purifying soil contaminated with organic pollutants, a purification material, and a purification material. More specifically, the present invention relates to a method for easily and quickly purifying soil contaminated with organic pollutants such as hydrocarbon compounds and organic halogen compounds, and a purification material and a purification material therefor.
[0002]
[Prior art]
Conventional methods for removing organic pollutants from soil contaminated with organic pollutants such as hydrocarbon compounds include physical treatment methods (for example, incineration and forced ventilation using blowers), chemical treatment methods (for example, Methods such as cleaning with surfactants, addition of reducing agents such as reduced iron, etc.) and biological treatment methods (methods of microbial degradation of organic pollutants) have been developed. Among these treatment methods, the biological treatment method is excellent in terms of low cost, simplicity, energy saving, and the like, and has attracted attention as a bioremediation technology, and technological development is progressing. Bioremediation technologies include (1) a method of adding organic substances that are nutrients for indigenous microorganisms and increasing or decreasing moisture and aeration to enhance microbial activity (biostimulation), (2) pollutants A method (bioaugmentation) of adding and decomposing microorganisms for decomposing DNA, (3) a method combining the methods (1) and (2), and the like have been developed.
[0003]
The conventional methods corresponding to the above (1) to (3) include (i) digging up contaminated soil, mixing organic waste and moisture adjusting material, and forcibly supplying oxygen with a blower in a closed state. After decomposing organic pollutants in the soil, a method of separating the moisture regulating material from the soil purified by sieving the mixture and restoring the purified soil obtained by digging up the soil (Patent Document 1) (Ii) soil contaminated with organochlorine compounds in a reducing atmosphere and in neutral conditions, optionally in the presence of heterotrophic anaerobic microorganisms and metallic iron, optionally organic compost or composted organic matter (See Patent Document 2), and (iii) compost and / or unfermented organic substances that have been fermented in soil contaminated with organic pollutants such as hydrocarbon compounds Append And (iv) soil contaminated with polycyclic aromatic hydrocarbons, compost fermented animal dung using grass, cultivated plants, and rice bran and rice bran In addition, a method for purifying by adding a fermented material obtained by secondary fermentation (see Non-Patent Document 1) is known.
[0004]
However, the conventional method of (i) described above has a blower device for blowing air into the contaminated soil and a closed system facility for preventing the contaminants volatilized from the soil into the air by the blower treatment from spreading to the surroundings. Since it needs to be used, the apparatus becomes large and not economical. In addition, since the purification process is performed under aerobic conditions while blowing air, it is difficult to decompose contaminants that are easily decomposed under anaerobic conditions, and it is difficult to completely decompose the contaminants.
[0005]
In addition, the conventional method (ii) is expensive because it is necessary to use a specific medium (for example, a medium for methanogenic microorganisms) for growing heterotrophic anaerobic microorganisms. In addition, microorganisms that favor and utilize low-molecular-weight nitrogen-containing substances with a molecular weight of 5000 or less contained in compost or the like proliferate abnormally, and are likely to cause death or inhibition of growth of microorganisms that assimilate organochlorine compounds. It is difficult for the pollutants to be quickly decomposed, and a bad odor may be generated.
[0006]
Even in the case of the conventional method (iii), as in the conventional method (ii), the unfinished mature compost and the organic material before fermentation contain a large amount of low molecular weight nitrogen-containing material having a molecular weight of 5000 or less. Microorganisms that favor and utilize low-molecular-weight nitrogen-containing substances proliferate abnormally, tend to cause killing or growth inhibition of microorganisms that assimilate hydrocarbon-based compounds, are difficult to decompose pollutants quickly, and have a foul odor There is a disadvantage that it is easy to generate.
[0007]
In the conventional method (iv), the secondary fermented product added to the contaminated soil is produced using a woody material such as sawdust, so that the secondary fermented product contains a low molecular weight nitrogen-containing substance. Since the amount is small, abnormal growth of microorganisms that favor and assimilate low molecular weight nitrogen-containing substances can be suppressed, and there is an advantage that the generation of malodor is small. However, when the contaminated soil contains a lot of organic substances other than bacteria and wood, it is difficult to decompose the pollutants. Moreover, it is necessary to use a fermented product (secondary fermented product) fermented by a specific method using a specific fermentation raw material as a purification material for purifying contaminated soil, and lacks commonality and versatility. .
[0008]
[Patent Document 1]
Japanese Patent Laid-Open No. 7-100459
[Patent Document 2]
JP-A-10-216694
[Patent Document 3]
JP 11-47727 A
[Patent Document 4]
JP 2000-254635 A
[Patent Document 5]
JP-T-2001-504029
[Non-Patent Document 1]
"Obayashi Institute of Technology Research Report" 2001, Vol. 63, p81-84
[0009]
[Problems to be solved by the invention]
An object of the present invention is to provide a purification method capable of easily and quickly purifying soil contaminated with organic pollutants such as hydrocarbon compounds and organic halogen compounds, and a purification material and a purification material therefor. That is.
The object of the present invention is to prevent hydrocarbons and organic halogen compounds, etc. while preventing the abnormal growth of microorganisms that favor and assimilate low molecular weight nitrogen-containing substances having a molecular weight of 5000 or less and the generation of malodor during purification treatment. To provide a method for smoothly and quickly purifying soil contaminated with organic pollutants, and a purification material and a purification material therefor.
Furthermore, the object of the present invention is to use organic pollutants such as hydrocarbon compounds and organic halogen compounds without using air blowing devices such as blowers or expensive special devices or facilities such as closed facilities. It is an object of the present invention to provide a method capable of purifying contaminated soil easily and at low cost, and a purification material and a purification material therefor.
[0010]
[Means for Solving the Problems]
The present inventors have repeatedly studied to achieve the above object. As a result, the soil contaminated with organic pollutants such as hydrocarbon compounds and organohalogen compounds, a cleaning material containing at least one of wheat bran and powder and aerobic to at least one of wheat bran and powder When at least one kind of purification material selected from purification materials including microorganism materials including microorganisms is added to perform purification treatment, without using a specific device or facility such as a blower device or a closed facility, The decomposition of organic pollutants such as hydrocarbon compounds and organic halogen compounds contained in soil is promoted while preventing abnormal growth of microorganisms that favor and utilize low molecular weight nitrogen-containing substances and the generation of malodors. It was found that the soil purification was carried out smoothly.
In addition, the present inventors use a purification material having a content of at least one of wheat bran and powder of 0.5% by mass or more at this time, which facilitates purification and favors low molecular weight nitrogen-containing substances. It has been found that it is effective in preventing the abnormal propagation of microorganisms that assimilate in the water and the generation of malodors.
[0011]
Furthermore, the present inventors add a purification material containing at least one of wheat bran and powder and a microbial material containing aerobic microorganisms to at least one of wheat bran and powder during the purification of contaminated soil. When at least one compound selected from acetic acid, lactic acid and methanol is added together with at least one cleaning material selected from purification materials, organic pollution such as hydrocarbon compounds and organic halogen compounds contained in the soil It was found that the decomposition of the substance was further promoted, and soil contaminated with organic pollutants could be quickly and quickly purified.
Further, the inventors of the present invention provide a purification material containing at least one of wheat bran and powder and / or a purification material obtained by adding a microbial material containing aerobic microorganisms to at least one of wheat bran and powder. In addition, it has been found that it is preferable to contain other components such as fully-ripened compost, digested sludge and humic acid with a low content of low molecular weight nitrogen-containing substances having a molecular weight of 5000 or less in order to promote purification.
In addition, the present inventors added the above-mentioned purification material at a ratio of 0.1 to 20 parts by mass with respect to 100 parts by mass of soil contaminated with organic pollutants such as hydrocarbon compounds and organic halogen compounds. The present inventors have found that it is desirable from the viewpoint of promotion of purification and completed the present invention on the basis of these various findings.
[0012]
That is, the present invention
(1) To soil contaminated with organic pollutants,
(A) a purification material containing at least one of wheat bran and powder; and (b) a purification material obtained by adding a microbial material containing aerobic microorganisms to at least one of wheat bran and powder;
A method for purifying soil contaminated with organic pollutants, characterized in that at least one purification material selected from the above is added for purification.
Furthermore, the present invention provides
(2) In soil contaminated with organic pollutants,
(A) a purification material containing at least one of wheat bran and powder; and (b) a purification material obtained by adding a microbial material containing aerobic microorganisms to at least one of wheat bran and powder;
Purification of soil contaminated with organic pollutants characterized in that at least one purification material selected from the above is added and at least one compound selected from acetic acid, lactic acid and methanol is added for purification Is the method.
[0013]
And this invention,
(3) The purification material (a) and the purification material (b) are at least one of wheat bran and powder, and 5 mass% or more based on the mass of the purification material (a) or the purification material (b). The purification method according to (1) or (2), which is contained at a ratio of
(4) The purification material (a) contains at least one of ripe compost, digested sludge and humic acid together with at least one of wheat bran and powder, and the purification material (b) is at least one of wheat bran and powder. And the purification method according to any one of the above (1) to (3), which contains at least one of fully-ripened compost, digested sludge and humic acid together with a microbial material containing aerobic microorganisms;
(5) A ratio of 0.1 to 20 parts by mass of at least one type of purification material selected from the purification material (a) and the purification material (b) with respect to 100 parts by mass of soil contaminated with organic pollutants The purification method according to any one of (1) to (4),
(6) At least one compound selected from acetic acid, lactic acid and methanol with respect to the total mass of the soil and at least one purification material selected from the purification material (a) and the purification material (b) The purification method according to any one of (2) to (5), which is added in an amount of 10 ppm or more; and
(7) The purification method according to any one of (1) to (6), wherein the soil contaminated with an organic pollutant is soil contaminated with a hydrocarbon compound and / or an organic halogen compound;
It is.
[0014]
The present invention also provides:
(8) Organic pollution characterized by containing (a) at least one of wheat bran and powder, or (b) containing microbial material containing aerobic microorganisms together with at least one of wheat bran and powder. It is a purification material for purifying soil contaminated with substances.
And this invention,
(9) The purification material according to (8), which contains at least one of wheat bran and powder in a proportion of 0.5% by mass or more based on the mass of the purification material;
(10) Ripe compost containing at least one of ripe compost, digested sludge and humic acid with at least one of wheat bran and powder, or ripe compost with microbial material containing at least one of wheat bran and bran and aerobic microorganisms The purification material according to (8) or (9), which contains at least one of sludge and humic acid; and
(11) The purification material according to any one of (8) to (10), which is a purification material for purifying soil contaminated with a hydrocarbon compound and / or an organic halogen compound;
It is.
[0015]
Furthermore, the present invention provides
(12) At least one compound selected from acetic acid, lactic acid and methanol is added to the purification material according to any one of (8) to (11) in an amount of 60 ppm or more with respect to the mass of the purification material. It is a purification material for purifying soil contaminated with organic pollutants.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
The purification method, purification material and purification material of the present invention can be applied to any soil contaminated with organic pollutants, and among them, purification of soil contaminated with hydrocarbon compounds and / or organic halogen compounds. Suitable for
Examples of soil contaminated with hydrocarbon compounds and / or organohalogen compounds to be purified by the purification method and purification material of the present invention include oils such as crude oil, heavy oil, light oil, kerosene, machining and equipment, etc. Examples include soils contaminated with organochlorine compounds and the like used for degreasing, cleaning, dry cleaning, and the like of lubricating oils, cutting oils, and electromechanical metal parts used.
Depending on the type of organic pollutant, the above-mentioned contaminated soil includes, for example, paraffinic and olefinic aliphatic hydrocarbon compounds, monocyclic aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene, phenanthrene, and anthracene. , Benzoanthracene, fluoranthene, pyrene, chrysene, benzofluoranthene, benzopyrene, etc. One type or two or more types of contaminating compounds such as organic chlorine compounds such as heptachlor epoxide, methoxy chloro, and benzene hexachloride are included.
Among them, the purification method and the purification material of the present invention are suitable for purifying soil contaminated with an organochlorine compound having a covalent double bond.
[0017]
The concentration of organic pollutants in the contaminated soil to be purified is not particularly limited. However, if the concentration of organic pollutants in the soil is too high, decomposition of organic pollutants will not proceed smoothly, and purification will take time. It becomes like this. From this point, the purification method, the purification material and the purification material of the present invention are suitable for purification of contaminated soil in which the concentration of organic pollutants is 10 g or less (10000 ppm or less) in 1 kg of soil. When the concentration of organic pollutants in the soil is 100 ppm or less, the organic pollutants contained in the soil are completely or almost completely decomposed in a short period of time by the purification method, purification material and purification material of the present invention. Thus, a good purification result can be achieved quickly.
[0018]
In the purification method of the present invention, the water content in the contaminated soil may vary depending on the type of soil, the type and concentration of organic pollutants contained in the soil, the type and concentration of other components contained in the soil, and the like. In general, when the moisture content of the contaminated soil is in the range of 30 to 90% by mass, particularly 50 to 70% by mass, the decomposition of the organic pollutants is further promoted and a good purification result is achieved quickly. be able to. Therefore, when the moisture content of the contaminated soil is lower than 30% by mass, water is added to the soil, and when the moisture content of the contaminated soil is higher than 90% by mass, the soil is dried, so that the moisture content of the contaminated soil is 30 to 30%. The purification treatment of the present invention is preferably carried out by adjusting to 90% by mass.
[0019]
In the present invention, in purifying soil contaminated with organic pollutants such as hydrocarbon compounds and organic halogen compounds, as a purifying material, (a) a purifying material containing at least one of wheat bran and powder [[ Purification material (sometimes referred to as “a purification material”); and (b) Purification material obtained by adding a microorganism material containing aerobic microorganisms to at least one of wheat bran and powdered powder [purification material (b) ” At least one type of purification material selected from the above is used.
In both the purification material (a) and the purification material (b), at least one of wheat bran and powder is 0.5% by mass or more based on the mass of the purification material (both wheat bran and powder) Is preferably contained in a proportion of 2% by mass or more, more preferably in a proportion of 5 to 100% by mass. .
When the content of at least one of wheat bran and powder in the purification material (a) and the purification material (b) is less than 0.5% by mass, organic pollutants such as hydrocarbon compounds and organic halogen compounds It becomes difficult to purify contaminated soil in a short period of time [hereinafter, the purifying material (a) and the purifying material (b) may be simply referred to as purifying material).
[0020]
The wheat bran used in the present invention is a wheat grain hull, as is well known, and the powder (sueko) is a powder containing an endosperm (wheat flour) adhering to the wheat hull and wheat bran. Is also obtained as a by-product during wheat milling.
The reason why wheat bran and / or powder has the effect of promoting the purification of soil containing organic pollutants such as hydrocarbon compounds and organic halogen compounds is not clear, but is presumed as follows.
That is, wheat bran and powder contain a high content (about 35% by mass) of a hemicellulose component, and the hemicellulose contains arabinoxylan having many arabinose side chains. In addition, wheat flour and powder have a C / N ratio of around 15 and a low moisture content (15% by weight or less), and are easy to create voids where oxygen is present in the soil. Therefore, when a purification material containing wheat bran and powder is added to soil contaminated with organic pollutants, microorganisms capable of decomposing arabinoxylan are selectively grown in the soil, and the microorganisms are mixed with hydrocarbon compounds and organic compounds. It is presumed to promote the decomposition of organic pollutants such as halogen compounds.
[0021]
Moreover, as a microbial material containing aerobic microorganisms used in the purification material (b), wheat bran and / or powder can be assimilated and a temperature of 55 ° C. even after treatment at a temperature of 80 ° C. for 10 minutes. Materials containing aerobic thermostable bacteria that can survive in the above are preferably used. Examples of such heat-resistant bacteria include Bacillus subtilis, Bacillus coagulans, Bacillus stearothermophilus, etc. Thermophilic and thermophilic actinomycetes such as Thermothernomyces vulgaris, Thermomonospora curvara, Humicola insokens, and Talaromyces demponty be able to. The purification material (b) used in the present invention can contain one or more of these heat-resistant bacteria. The aforementioned heat-resistant bacteria are commercially available as microbial preparations and the like, and commercially available ones may be used as they are. In some cases, the aforementioned thermostable bacteria may be cultured and grown. Many of these heat-resistant bacteria have a high ability to decompose wheat bran or powder and are excellent in the ability to decompose organic substances at high temperatures. In the purification material (b) containing a microbial material containing aerobic microorganisms, 10 aerobic microorganisms are added per 1 g of the purification material (b). ⁵ It is preferable to contain in the ratio more than CFU (Colony Forming Unit).
It is preferable to include an activator that activates the aerobic microorganism in the microbial material containing the aerobic microorganism, since the growth of the aerobic microorganism is further promoted and the purification of the contaminated soil is further promoted. Examples of the aerobic microorganism activator include humic acid described later and a pH adjuster such as an alkali capable of adjusting the pH of the purification material (b) to those suitable for the growth of the aerobic microorganism. .
[0022]
The purification promoter (a) and / or the purification material (b) used in the present invention can contain other components as needed in addition to the microbial material containing wheat bran, powder and aerobic microorganisms. . Another component to be contained in the purification accelerator is a high molecular weight organic substance in which the content of a low molecular weight nitrogen-containing compound (generally a nitrogen-containing compound having a molecular weight of 5000 or less) that is easily decomposed by microorganisms is 1% by mass or less. Preferably used. If the other components contain a large amount of low-molecular-weight nitrogen-containing compounds (generally nitrogen-containing compounds with a molecular weight of 5000 or less), abnormal growth of microorganisms that favor and utilize low-molecular-weight nitrogen-containing substances during soil purification Odor is likely to occur, which is not preferable.
Other components having a low content of low molecular weight nitrogen-containing compounds that can be used with microbial materials including aerobic microorganisms, at least one of wheat bran and powder, in particular, at least one of fully matured compost, digested sludge and humic acid Preferably, the purification accelerator can contain one or more of the other components described above.
When other components such as fully-ripened compost, digested sludge and humic acid are contained in the purification material, the content of the other components is 99.5% by mass or less based on the mass of the purification material. It is preferably 98% by mass or less, and more preferably 95% by mass.
[0023]
In the present invention, as the matured compost that can be contained in the purification material, for example, manure of livestock such as chickens, cattle, pigs, horses, food residues (for example, food production / processing plants, wholesale stores, etc.) Various food residues discharged, various food residues discharged from restaurants, hotels, schools, homes, etc.), plant generating materials (eg leaves, stems, roots, fruits, fruit hulls, woody systems derived from plants) Examples include compost that has been completely decomposed by microorganisms using organic materials such as building waste materials and activated sludge as fermentation raw materials.
In the present invention, the digested sludge that can be contained in the purification material is sludge obtained by completely decomposing sludge generated in a sewage treatment plant or the like in a digestion tank.
[0024]
In the present invention, the humic acid that can be contained in the purification material includes alkali-soluble amorphous high-molecular organic acids contained in young coals such as peat and lignite with a low degree of coalification, and the amorphous Examples thereof include nitrohumic acid obtained by oxidative decomposition of a high molecular organic acid with nitric acid and salts thereof. Moreover, the purification material may contain, as humic acid, a substance containing humic acid such as juvenile charcoal such as peat and lignite instead of humic acid. Among them, it is possible to use humic acid, nitrohumic acid or salts thereof separated from them without using young coals such as peat and lignite as they are. It is desirable because microorganisms useful for decomposing organic pollutants such as halogen compounds can be grown.
[0025]
The pH of the purification material used in the present invention may vary depending on the type of soil to which the purification material is added, the type of organic pollutants contained in the soil, etc., but is generally in the range of 3 to 8.5. Is preferable, and the range of 4 to 7 is more preferable. When the pH of the purification material is lower than 3 or higher than 8.5, the organic pollutants are decomposed when added to soil contaminated with organic pollutants such as hydrocarbon compounds and organic halogen compounds. It becomes difficult for microorganisms to grow in the soil and to purify the soil in a short time.
Depending on the original pH of the purification material and the pH of the soil, it is preferable to use alkali and / or acid as a pH adjuster so that the pH of the purification material is in the above-described range. Examples of the alkali used for adjusting the pH include calcium carbonate; lime and slaked lime; alkali metal hydroxides and carbonates; calcined ash of coal, sludge, livestock feces, and the like. Various inorganic acids and organic acids can be used.
[0026]
The amount of the at least one purification material selected from the purification material (a) and the purification material (b) for the contaminated soil is the content of at least one of wheat bran and powder in the purification material, aerobic Content of microbial materials including microorganisms, types and contents of other components contained in purification materials, types of soil to be treated, types and concentrations of organic pollutants contained in soil, contained in soil Generally, at least one of a purification material (a) and a purification material (b) (a plurality of purification materials) with respect to 100 parts by mass of contaminated soil Is added at a ratio of 0.1 to 20 parts by mass, particularly 1 to 5 parts by mass, the organic pollutants are decomposed well during the purification treatment, and the molecular weight is 5000 or less. Contains molecular weight nitrogen Is prevented overgrowth of microorganisms assimilate prefer quality, it is possible to prevent the occurrence of offensive odors, moreover preferable because mixing operation is easy.
When the amount of the purification material added is less than 0.1 parts by mass with respect to 100 parts by mass of the contaminated soil, microorganisms that decompose organic pollutants are difficult to grow in the soil, and it takes a long time to purify the contaminated soil. On the other hand, if it exceeds 20 parts by mass, abnormal growth of microorganisms that favor and assimilate a low molecular weight nitrogen-containing substance having a molecular weight of 5000 or less, malodor and the like are likely to occur.
[0027]
In the present invention, when performing purification by adding at least one of the purification material (a) and the purification material (b) to the soil contaminated with organic pollutants, the purification material (a) and the purification material ( It is preferable to add at least one compound selected from acetic acid, lactic acid and methanol together with at least one of b). By further adding at least one compound selected from acetic acid, lactic acid and methanol to the contaminated soil, microorganisms that decompose organic pollutants in a short period of time are greatly grown in the soil, thereby generating harmful gases. While suppressing, organic pollutants in the soil will be decomposed into innocuous substances in a short period of time, and the soil will be purified quickly.
In purifying the contaminated soil, only one of compounds selected from acetic acid, lactic acid and methanol may be contained together with at least one of the purification material (a) and the purification material (b). Seeds may be included, or three may be included.
[0028]
The amount of at least one compound selected from acetic acid, lactic acid and methanol is the kind of soil, the kind and concentration of organic pollutants contained in the soil, the purification material (a) and / or the purification material (b). Although it can be adjusted according to the contents etc., it is generally preferable to add at least one selected from acetic acid, lactic acid and methanol to the total mass of the contaminated soil and the purification material at a ratio of 10 ppm or more, 20 ppm It is more preferable to add at the above ratio, and it is further preferable to add at a ratio of 20 to 50 ppm.
When the addition amount of at least one compound selected from acetic acid, lactic acid and methanol is less than 10 ppm with respect to the total mass of the contaminated soil and the purification accelerator, microorganisms that decompose organic pollutants in the soil in a short period of time. In some cases, the organic pollutants in the soil cannot be rapidly decomposed into innocuous substances while being prevented from growing or suppressing the generation of odors and harmful gases.
On the other hand, if the addition amount of at least one compound selected from acetic acid, lactic acid and methanol exceeds 100 ppm with respect to the total mass of the contaminated soil and the purification accelerator, the activity of decomposing organic pollutants by microorganisms is reduced. It is not preferable because it lowers.
[0029]
Method of adding the purification material (a) and / or the purification material (b) to the contaminated soil, or the purification material (a) and / or the purification material (b) and selected from acetic acid, lactic acid and methanol The method of adding at least one compound is not particularly limited, and at least one compound selected from the purification material (a) and / or the purification accelerator (b), acetic acid, lactic acid and methanol is contained in the soil. Any method may be used as long as it can be uniformly mixed.
When adding at least one compound selected from acetic acid, lactic acid and methanol together with the purification accelerator (a) and / or (b) to the contaminated soil, the purification material (a) and / or the purification material (b) And the above compounds may be added simultaneously to the contaminated soil or sequentially. Alternatively, at least one compound selected from acetic acid, lactic acid and methanol may be mixed in advance with at least one of the purification accelerator (a) and the purification material (b), and the mixture may be added to the contaminated soil. Good.
In the case where at least one compound selected from acetic acid, lactic acid and methanol is mixed in advance in the purification material, acetic acid, lactic acid and methanol are added to the purification material (a) and / or the purification material (b). It is preferable to mix at least one selected compound at a ratio of 60 ppm or more.
[0030]
It contains at least one of wheat bran and powder and optionally further other components (ripened compost, digested sludge, humic acid, etc.) or at least one of wheat bran and powder and aerobic microorganisms The above-described purification material (b) containing microbial material and optionally other components (ripe compost, digested sludge, humic acid, etc.) is mixed with at least one compound selected from acetic acid, lactic acid and methanol Any mixture can be stored, distributed, and sold independently as a purification accelerator or purification material, and therefore the present invention includes such a purification accelerator and purification material within the scope of the present invention.
By adding the above-described purification accelerator and purification material of the present invention to soil contaminated with organic pollutants such as hydrocarbon compounds and organic halogen compounds, soil can be purified with extremely simple operations. it can.
[0031]
At least one of the purification material (a) and the purification material (b) is added to the soil contaminated with organic pollutants such as hydrocarbon compounds and organic halogen compounds, or the purification material (a) and In performing purification by adding at least one compound selected from acetic acid, lactic acid and methanol together with at least one kind of purification material (b), the purification material (a) and / or the purification material (b) are used. The contaminated soil mixture added, or the contaminated soil mixture to which at least one compound selected from acetic acid, lactic acid and methanol is added together with the purification material (a) and / or the purification material (b) is put into a deposited state, and the sediment In order to ensure the uniform decomposition of organic pollutants as a whole, the soil is purified by stirring and turning over once or twice every two months. It can be carried out smoothly.
The pH of the contaminated soil mixture during the purification treatment is generally 4 to 9, particularly 5 to 8, so that the degradation of organic pollutants such as hydrocarbon compounds and organic halogen compounds is improved, and purification can be performed in a short period of time. It is preferable from the point.
[0032]
The period required for remediation varies depending on conditions such as the type and concentration of organic pollutants contained in the contaminated soil, the moisture content of the contaminated soil, and the temperature at the time of purification, but in general, organic pollutants in the soil It can be considered that the purification has been completed when the concentration of is less than the environmental standard (for example, 0.03 ppm or less for trichlorethylene).
The soil after purification by adopting the purification method or purification material of the present invention, the organic pollutants in the soil are almost completely decomposed and removed, and can be returned to the natural environment as it is, It can also be used for horticultural soils and other applications.
[0033]
【Example】
EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples.
[0034]
<< Reference Example 1 >> [Manufacture of woody compost]
Water was added to the ground chips of the deforested timber and mixed uniformly to adjust the water content to 60% by mass for deposition. This was stirred and turned over every month for fermentation, and after 6 months, the fermentation was terminated to produce a woody compost.
[0035]
<< Reference Example 2 >> [Manufacture of digested sludge]
Add equal mass of tap water to the digested sludge generated at the sewage treatment plant in Saitama Prefecture, stir well, then centrifuge at 3000G for 10 minutes, add equal mass of tap water to the resulting precipitate and 3000G The washing process of collecting the precipitate produced by centrifugation for 10 minutes was repeated 5 times, and the resulting precipitate was used as digested sludge.
[0036]
Example 1
(1) Wheat bran and the woody compost prepared in Reference Example 1 or the digested sludge prepared in Reference Example 2 were mixed at the ratio shown in Table 1 to prepare purification materials A to G, respectively.
(2) To 250 g of commercially available black clay (moisture content 51.3 mass%), add 5 g of each of the purification materials prepared in (1) above, and further mix acetic acid or methanol in the amounts shown in Table 2 below. A black clay mixture was prepared. When the pH of the black clay mixture was measured, it was as shown in Table 2 below.
Further, as a control, black soil to which neither a purification material, acetic acid nor methanol was added was prepared, and the pH thereof was measured.
(3) The black clay mixture prepared in the above (2) and the black clay for control are put into each flask (760 ml volume), and 2.5 mg of trichlorethylene is added thereto (concentration of trichlorethylene: 10 ppm with respect to the mass of black clay, A butyl rubber stopper processed with Teflon (registered trademark of DuPont) after addition was added to the total mass of the black clay and the purification material, and left in a thermostatic bath at 25 ° C. for 3 weeks. During that time, the mixture was lightly agitated once a week with the stopper kept on.
(4) After 3 weeks, the concentration of trichlorethylene in the black clay mixture and black clay (for control) was measured by the following method, and as shown in Table 2 below.
[0037]
[Measurement of trichlorethylene content (concentration) in soil after purification]
After the test for 3 weeks, the gas in the head space of the test flask with a butyl rubber stopper was collected with a syringe, and the trichlorethylene concentration in the gas was analyzed by GC-MS. (The concentration of trichlorethylene in the gas in the headspace portion is proportional to the concentration of trichlorethylene in the soil). The conditions of GC-MS analysis are JIS K
0125 (Test method for volatile organic compounds in water / waste water).
[0038]
[Table 1]

[0039]
[Table 2]

[0040]
As seen from the results in Table 2 above, in Experiment No. 1 (control example), the soil (black soil) contaminated with trichlorethylene was subjected to purification treatment without adding any of the purification materials, acetic acid and methanol. The content of trichlorethylene in the soil after 3 weeks was 8.8 ppm, and the degree of purification was low.
On the other hand, in Experiment Nos. 2 to 6, the content of trichlorethylene in the soil after 3 weeks was obtained by adding a purification material containing wheat bran to the soil contaminated with trichlorethylene. Was significantly lower than that of Experiment No. 1, and good purification results were obtained.
Further, in Experiment Nos. 7 to 10, the soil contaminated with trichlorethylene was purified by adding acetic acid or methanol together with the purification material containing wheat bran, thereby containing trichlorethylene in the soil after 3 weeks. The amount was greatly reduced, and very good purification results were obtained.
[0041]
Example 2
(1) 5 kg of 1 kg of commercially available black clay is prepared, and 10 g of heavy oil A (1% by mass with respect to the weight of the black clay) is added to each, and left in a room at a temperature of 25 ° C. for 1 month. Each contaminated soil was prepared. When the oil concentration in each heavy oil contaminated soil was measured by the following method, it was around 2500 ppm as shown in Table 4 below.
[0042]
[Measurement of heavy oil concentration in soil]
To 5 g of sample soil, add 3 drops of 1N hydrochloric acid with a dropper and add 5 ml of saturated saline and 10 ml of extraction solvent (trichlorotrifluoroethylene), and shake at room temperature (25 ° C.) for 5 hours. Oil (heavy oil) in the soil was extracted into trichlorotrifluoroethylene. After extraction, the trichlorotrifluoroethylene layer is separated, and the concentration of oil (heavy oil) contained therein is measured using an oil concentration meter (“OCMA-350” manufactured by Horiba, Ltd.). The concentration of heavy oil contained in the sample soil was determined.
[0043]
(2) Wheat bran, humic acid ("HA-01" manufactured by Ternite Co., Ltd.), calcareous fertilizer ("Kumiai Calcium Carbonate Fertilizer" manufactured by Murasaki Lime Industry Co., Ltd .; for pH adjustment) and aerobic microbial materials (Nisshin Flour Milling) Purifying materials a to c shown in Table 3 below were prepared using “Accel Component” manufactured by Co., Ltd.
(3) To each 1000 g of heavy oil-contaminated soil prepared in (1) above, each of the purification materials a to c prepared in (2) above is added in the amounts shown in Table 4 below, and each is compact. The fermentation reactor was filled and allowed to stand for 14 days at an outside air temperature of 20 ° C (soil temperature in the fermentation reactor: about 25 to 30 ° C). After 14 days, the soil was taken out from the fermentation reactor, and the oil (heavy oil) concentration in the soil was measured by the method described above, and the reduction rate of the oil (heavy oil) concentration was determined from the measured value. As shown.
(4) Also, as a control, the heavy oil-contaminated soil prepared in (1) above was filled in a small fermentation reactor without adding a purification material, and left for 14 days in the same manner as in (3) above. After 14 days, the soil was taken out from the fermentation reactor, and the oil (heavy oil) concentration in the soil was measured by the method described above, and the reduction rate of the oil (heavy oil) concentration was determined from the measured value. As shown.
[0044]
[Table 3]

[0045]
[Table 4]

[0046]
As seen from the results in Table 4 above, in Experiment No. 12 (control example), the soil treated with heavy oil (black soil) was purified without adding the purification material, so that the soil after 14 days The decrease rate of the oil (heavy oil) concentration was as low as 8.7%.
On the other hand, in Experiment Nos. 13 to 16, by adding a purification material containing wheat bran to soil contaminated with heavy oil, the concentration of heavy oil in the soil after 14 days was changed to Experiment No. 12 Compared to the above, the oil concentration decrease rate exceeded 50%, and good purification results were obtained.
In particular, in Experiment No. 16 in which the purification material c containing humic acid and aerobic microorganism material together with wheat bran was added to heavy oil-contaminated soil, the reduction rate of the oil concentration was extremely high, and a very good purification result was obtained. .
[0047]
【The invention's effect】
In the case of the present invention, decomposition of organic pollutants such as hydrocarbon compounds and organic halogen compounds contained in soil is promoted more than before, and soil contaminated with the organic pollutants is smoothly purified in a short period of time. can do.
In addition, according to the present invention, when purifying soil contaminated with organic pollutants such as hydrocarbon compounds and organic halogen compounds, microorganisms that favor low-molecular-weight nitrogen-containing substances and assimilate abnormal odors or malodors. The contaminated soil can be purified smoothly in a short period while preventing the occurrence.
Furthermore, according to the present invention, soil contaminated with organic pollutants can be easily and quickly purified at low cost without using specific devices or facilities such as blower devices or closed facilities. it can.
In the present invention, the purification material (a) containing at least one of wheat bran and powder in soil contaminated with organic pollutants such as hydrocarbon compounds and organic halogen compounds, and at least one of wheat bran and powder And at least one compound selected from acetic acid, lactic acid and methanol together with at least one selected from the purification material (b) containing a microbial material including aerobic microorganisms, Organic pollutants are decomposed in a shorter time, and extremely good purification results can be obtained.

Claims

To soil contaminated with organic pollutants,
(A) a purification material containing at least one of wheat bran and powder; and (b) a purification material obtained by adding a microbial material containing aerobic microorganisms to at least one of wheat bran and powder;
A method for purifying soil contaminated with organic pollutants, wherein at least one purification material selected from the above is added for purification.

To soil contaminated with organic pollutants,
(A) a purification material containing at least one of wheat bran and powder; and (b) a purification material obtained by adding a microbial material containing aerobic microorganisms to at least one of wheat bran and powder;
Purification of soil contaminated with organic pollutants characterized in that at least one purification material selected from the above is added and at least one compound selected from acetic acid, lactic acid and methanol is added for purification Method.

In the purification material (a) and the purification material (b), at least one of wheat bran and powder is in a ratio of 5% by mass or more with respect to the mass of the purification material (a) or the purification material (b). The purification method according to claim 1 or 2, comprising:

The purification material (a) contains at least one of fully matured compost, digested sludge and humic acid together with at least one of wheat bran and powder, and the purification material (b) contains at least one of wheat bran and powder and aerobic. The purification | cleaning method of any one of Claims 1-3 which contains at least 1 sort (s) of fully-ripened compost, digested sludge, and humic acid with the microbial material containing microorganisms.

At least one kind of purification material selected from the purification material (a) and the purification material (b) is added at a rate of 0.1 to 20 parts by mass with respect to 100 parts by mass of the soil contaminated with organic pollutants. The purification method according to any one of claims 1 to 4.

10 ppm or more of at least one compound selected from acetic acid, lactic acid and methanol with respect to the total mass of the soil and at least one purification material selected from the purification material (a) and the purification material (b) The purification method according to any one of claims 2 to 5, which is added in an amount.

The purification method according to any one of claims 1 to 6, wherein the soil contaminated with an organic pollutant is soil contaminated with a hydrocarbon compound and / or an organic halogen compound.

Contaminated with an organic pollutant characterized in that it contains (a) at least one of wheat bran and powder, or (b) contains microbial material containing aerobic microorganisms together with at least one of wheat bran and powder. Material for purification to clean up the soil.

The purification material according to claim 8, comprising at least one of wheat bran and powder at a ratio of 0.5% by mass or more based on the mass of the purification material.

Ripe compost, digested sludge and humus together with microbial materials containing at least one of wheat bran and bran and aerobic microorganisms, containing at least one of matured compost, digested sludge and humic acid with at least one of wheat bran and powder The purification material according to claim 8 or 9, comprising at least one acid.

The purification material according to any one of claims 8 to 10, which is a purification material for purifying soil contaminated with a hydrocarbon compound and / or an organic halogen compound.

The purification material according to any one of claims 8 to 11, wherein at least one compound selected from acetic acid, lactic acid and methanol is added in an amount of 60 ppm or more with respect to the mass of the purification material. Purifier for purifying soil contaminated with organic pollutants.