【０００１】
【発明の属する技術分野】
本発明は、石油系汚染土壌等の（１）早期浄化法、（２）緑化法、更には、（３）それらの方法を行うためのプラント設計法に関する。
【０００２】
【従来の技術】
従来の石油系汚染土壌の処理方法は、（１）微生物分解法、（２）堆肥添加法、（３）電極による熱分解法、（４）溶媒洗浄法、（５）磁選処理法、（６）加熱分離法、（７）焼却法、（８）紫外線照射法等を挙げる事ができる。しかしながら、これらの浄化法のうち、汚染土壌１ｍ３当たり、２万円以下の経費で済む処理方法は２，３に限定される。そのうち、微生物分解法は油分が多い土壌には、分解微生物の生育活性が阻害されるため事実上使えない。また、光照射法も土壌スラリーは光を通しにくいので、実験室レベルならともかく、現場の大量土壌に有効照射するのは実際は難しい。また、数百℃で油分を揮発させたり、燃焼させる方法も、ダイオキシン等の有害物質を大気に放出する危険性が無視できない。更に、溶剤抽出法に関しても、処理した後の土壌の再利用を考えていないだけでなく、ガソリンスタンド跡地のような面積が小さい場合はプラントを現場では組み立てられないといった問題点が残る。本発明は、これらの点に考慮してなされたものであり、（１）石油汚染土壌１ｍ３当たり、２万円以下の経費で行え、（２）短期間で浄化が可能であり、（３）薬剤（生石灰、過酸化水素等）の残留問題が比較的少なく、（４）３００℃以上といった大きなエネルギーも使わず、（５）処理後の土壌を緑化等に利用可能、という５点において、従来の技術と比べ一定の競争力があるものと考えられる。
【０００３】
本発明の浄化原理は、請求項１に挙げた、アルカリ・過酸化水素法と、請求項３に挙げたフェントン反応法に大別できる。まず前者に関する関連特許としては、まず米国会社であるコンティニュアム エンバイロンメンタル インコーポレーテッドの「有機汚染物質の処理方法（特表２００１−５１３０２１）」を挙げる必要がある。しかし、この米国会社の方法では、何よりも、「生石灰等アルカリ剤を加えていない点」が本発明と根本的に異なる。本発明の実施例で示したように過酸化水素のみの添加で石油汚染土壌の酸化処理を行う場合は、（ケン化剤としても作用する）生石灰の添加を伴う区と比べ、格段に油状物質分解能力が劣り、特に油分の割合が多い場合は十分に浄化する事はできないし、緑化にも使えない。また、この特許では、請求項１において「パイプ手段によって連結している連続した独立の処理装置」を用いて「該土壌を処理装置から処理装置に移動させる」方式に限定した上で全ての権利請求を行っているが本発明においては、「パイプ手段によって連結している連続した独立の処理装置」を用いない「単独の処理槽」によっても浄化を行えるため、そういった面でも、この米国会社特許とは競合しないと判断できる。
【０００４】
また、請求項３に関する関連特許（すなわちフェントン反応を用いた浄化）に関しては、株式会社荏原製作所の「固体中のダイオキシン類の分解方法（特開２０００−１９７８６７）」が挙げられるが、本特許は、対象をあくまでもダイオキシンに限定しており、石油汚染土壌等に関しては請求範囲を広げていないだけでなく、用いる鉄化合物に関しても硫酸第一鉄に限定している。それに対し、本発明においては、このフェントン反応を石油汚染土壌浄化に適用した結果、良好な結果が得られたので、ダイオキシン以外の全ての有機化合物汚染土壌浄化にも適用しうる新技術としてフェントン反応に特許請求するものである。また、フェントン反応に用いる鉄化合物に関しても硫酸第一鉄に限定せず、硫化鉄等、二価の鉄イオンを供給する全ての鉄化合物に関して請求を行う点が異なっている。また、同様の特許として、藤堂福蔵氏出願の「ジベンゾ−ｐ−ジオキシンおよびジベンゾフランの処理方法（特開２００１−２４０５９６）」も挙げる必要があるが、本特許も、特許請求の対象をダイオキシン類のみに限定しており、石油汚染土壌等、ダイオキシン以外の有機化合物に適用できる事は対象外としており、ダイオキシン以外の物質を浄化する限りにおいては、本発明の請求項３とは競合しない。更に、二価の鉄イオンの供給源として、特に硫化鉄、酸化鉄や、それを含む火山灰や鉄鋼スラグが有効である事に関しても、触れていないため、そういった点に関しても、本発明の独自性及び権利は主張できるものと考えられる。
【０００５】
また、本発明は、石油系汚染土壌の浄化法の原理だけでなく、それを行うためのプラントに関しても特許請求を行っている（請求項６〜９）。そのうち、請求項６に示したジュール熱を活用する方式に対する関連特許として、株式会社間組の「汚染土壌の浄化方法（特開２００２−１２９９）」を挙げる必要があるが、この間組の方法では単に導電性物質を添加し加熱するのみなので、比較的分解が容易なトリクロロエチレンなら分解できても、石油汚染土壌に関しては有効な浄化が期待できない。また、溶融固化法やアルカリ触媒化学分解法においても同様なプラントを設置するが、両者とも３００℃以上の高温を要求し設備がそれだけ大がかりになるのに対し、本発明のプラントでは１００℃以下の比較的低温で作用させるためイニシャルコストが安いメリットがある。
【０００６】
また、請求項７で示した省エネ型プラントに関しての関連特許として、三菱重工株式会社の「焼却灰の処理方法およびその装置（特開２００１−１３７８０３）」を挙げる必要があるが、この特許はダイオキシン汚染飛灰のみに限定されたものであり、飛灰以外の土壌、底泥や、石油等のダイオキシン以外の有機物質汚染に関しては対象としていない。また、焼却場排水のみに限定しており、地熱発電所、温泉等の自然エネルギーや、原子力発電所、精錬所等の工場排水は対象としておらず、それでは十分な省エネルギー効果が期待できない。
【０００７】
最後に、請求項８，９に示した浄化能を有した移動車両・船舶プラントに関しては、従来の技術に特記すべきものを発明者らは知らない。例えば、油回収船は多く建造されていても、その油回収船の中で浄化も同時に行える船舶は現在、存在せず、そのため廃棄物輸送コストがかかる上に、油回収量の制約も大きい。従って、本発明（請求項８，９）によって、環境浄化の機動性を向上させうる事が期待される。また、請求項１０に示した浄化処理を部分的に終えた土壌を緑化に用いるという概念の従来の技術も報告されていない。特に本発明では、請求項１においては、土壌浄化に生石灰等を用いるが、生石灰や消石灰は土壌改良材若しくは肥料として農業で一般的に用いられており、この浄化処理で残留した生石灰、消石灰等や、分解された石油成分を、植物栄養源に用いる方向性を示したのは、本発明が最初であろう。
【０００８】
【発明が解決しようとする課題】
石油系汚染土壌等を、（１）低コストで、迅速に、環境に優しい形で浄化する方法、（２）浄化処理済みの土壌を用いて緑化する方法、（３）前述の２処理を行うためのプラント設計法、の３つを提供する事を課題とする。
【０００９】
【課題を解決するための手段】
上記目的を達成するためには、石油系汚染土壌に水を加えスラリー化した上で、生石灰等のアルカリ剤添加と過酸化水素添加と加温加圧処理の３処理を組み合わせればよい。あるいは、土壌スラリーに硫化鉄、硫酸第一鉄等の二価の鉄イオンを供給しうる鉄化合物、若しくはそれらを含む火山灰、鉄鋼スラグと過酸化水素添加を組み合わせるフェントン反応を用いても良い。また、更に必要なら、（１）オゾン、光照射、次亜塩素酸等の各種酸化処理、（２）触媒、（３）曝気、若しくは撹拌、（４）活性炭等炭化素材添加の計４処理のうちの１つ、若しくは複数を組み合わせれば更に分解能を促進させる事ができる。また、土壌等の加温処理（常温〜１００℃）を行う場合は、スラリー化した汚染土壌等を地中等に設置した容器内に入れた上で、電極を設置し通電により発生したジュール熱を利用できるよう設計されたプラントを用いても良い。また、地熱発電所、精錬所、原子力発電所、火力発電所、ゴミ等焼却場等の大量の熱を発生するプラントの高熱工業排水あるいは温泉水を用いて、請求項１〜５の方法を用いて浄化を行えるよう設計された省エネ型浄化プラントを設置したり、請求項１〜５の方法を行える設備一式（スラリー等を撹拌可能な装置、過酸化水素等酸化剤添加装置、生石灰等アルカリ剤添加装置、紫外線照射装置、触媒添加装置、加熱装置、加圧装置等）を設置し、原位置で石油等に汚染された土壌や海水等を浄化できるよう設計された移動車両・船舶プラントを用いるのも効果的である。更に、これらの方法を用いて部分浄化した土壌等に植栽を行う事を特徴とする植物環境修復法もしくは緑化法や、該土壌等に、植栽を行わずに単に有害物質分解微生物群や堆肥を添加する微生物環境修復法も効果的に働く事が期待される。また、油状汚染土壌等をこれらの方法を用いて処理した処理物を酸性土壌矯正用の土壌改良材、若しくは肥料として花卉栽培、林業等に用いるのも、資源循環促進、処理コスト回収の両面で有効である。
【００１０】
【発明の実施の形態】
以下、本発明を更に詳細に説明する。有機物質を含有する排水に、（１）生石灰等のアルカリ剤添加と、（２）過酸化水素添加と、（３）室温〜１００℃の範囲（できれば８０℃前後）での加温処理、若しくは加圧加温処理（〜２００℃）の計３処理を組み合わせればよい。この時、加圧せずに単に加温する場合は、撹拌若しくは曝気を行った方が良い。それだけで、生石灰処理のみや、過酸化水素処理のみや、生石灰と過酸化水素を常温処理のみと比較し、石油分解能が格段に高まる。なお、この際、生石灰の添加割合は、石油汚染土壌重量の１〜３割程度、過酸化水素の添加割合は、石油汚染土壌重量の５〜３０％を目安に適宜調節すればよい。過酸化水素の添加量が多い程、石油分解能は高まるが、その分、コストが割高になるので、費用対効果を念頭に条件検討を行うべきである。この反応の原理は、過酸化水素添加により発生するヒドロキシラジカルの発生がアルカリ条件、高温条件で高まると同時に、エステル結合を含む油分の場合は同時にケン化効果もあるものと推測できる。また、ここでアルカリ剤として生石灰を用いるのは、強アルカリ状態にしても、水や空気中の二酸化炭素と反応して、消石灰を経て炭酸カルシウムに自然に中和される効果が期待されると同時に、熱源としても利用できるからである。また、生石灰は過酸化水素と同様、値段が安く、処理経費が安価に抑えられる。これらアルカリ剤及び過酸化水素の添加は一度に投入するのではなく、一定の時間間隔をおいて追加添加を繰り返す方が、作用時間全体を通してのヒドロキシラジカルの発生効率及び熱発生効率を高める上で望ましい。なお、生石灰の代わりに、水酸化ナトリウム等を用いても良いが、その場合は、処理後に酢酸や木酢液等で中和処理を行う必要がある。また、これらの反応を行う上で、単なる加温処理（常温〜１００℃）でも良いが、多少コストがかかっても、浄化時間を早めたい場合は、加温加圧法（〜２００℃）の方が効果的なのはパルプ業界の例から考えても明白である。実際、発明者らも石油汚染土壌を通常の高圧滅菌器（オートクレーブ）で１２７℃２時間処理したものと、単に同時間８０℃処理したものとを比較した結果、前者の分解効率の方が優れていた事を確認している。
【００１１】
また、アルカリ・過酸化水素法にこだわる必要はなく、（鉄汚染がやや気にはなるが）フェントン反応を石油汚染土壌に用いるのも有効である。その場合、石油系汚染土壌に水を加えスラリー化した上で、（１）硫化鉄、硫酸第一鉄等の二価の鉄イオンを供給できる鉄化合物、若しくは鉄化合物を含む火山灰、鉄鋼スラグ等と、（２）過酸化水素との２つを添加した上で、更に必要なら加圧加温（若しくは加温のみ）すれば良い。ダイオキシンの場合は、フェントン方法が有効に働くという特許が既に出願され、その点においては発明者らは特許請求はできないが、今回、発明者らは石油汚染土壌に関してフェントン反応法を実際に試してみたところ良好な浄化が確認できたので、新たな技術として特許請求を行う事と
した。また、
【従来の技術】の欄においても述べたように、鉄化合物の中でも特に硫化鉄が有効である事を発明者らは見出し、それを含んだ火山灰等も土壌浄化に利用できる事を請求項に含めた点が本発明の新規性となろう。また、二価鉄イオンの供給源として鉄鋼スラグを挙げ、鉄鋼スラグの有効利用を含めた点も本発明の独自性として権利請求を行えるものと考える。なお、このフェントン反応を行う場合、ｐＨ６以下の酸性で作用させた方が分解が進む事が期待される。
【００１２】
また、アルカリ・過酸化水素法にせよ、フェントン反応法にせよ、石油分解反応を更に促進するためには、一般に促進酸化反応で用いられている手段等を適宜、組み合わせれば良い。具体的に言えば、（１）オゾン、光照射、次亜塩素酸等の各種酸化処理、（２）触媒、（３）曝気、若しくは撹拌、（４）活性炭等炭化素材添加の計４処理のうちの１つ、若しくは複数を組み合わせる事が有効である。ただ、土壌等を処理する場合は、次亜塩素酸処理で生ずる塩素が、新たな有害物質産生に関わる可能性もあるので、その点は注意は要する。また、これらの処理を行えば、それだけ経費もかかるので、できるだけ単純なシステムで浄化を行った方がよい。そういった意味で、環境汚染物を浄化する場合は、生石灰と過酸化水素を添加して熱処理する方法が最も単純かつ有効であると考えられる。
【００１３】
これらの一連の方法を用いれば、単に石油汚染土壌を浄化するだけでなく、土壌、底泥、食品、厨房排水等中のダイオキシン、ＰＣＢ、環境ホルモン、残留農薬、動植物油脂、エストロゲン、残留化学兵器等の各種有害有機物質や臭気物質を除去する事も可能であり、幅広く環境中、食品中の有害有機物質処理に用いる事ができる。
【００１４】
なお、広大な敷地で、大量の石油等汚染土壌を処理する必要がある場合、土壌等の加温処理を行う際、スラリー化した汚染土壌等を地中等に設置した容器内に入れた上で、電極を設置し通電により発生したジュール熱（〜１００℃）により請求項１〜５の処理を行えるよう設計されたプラントを用いれば、比較的、安価に目的を達成する事ができよう。この際、水分が蒸発乾固してしまわないように、簡単なオフガスフードを設置する必要がある。また、可能なら、土壌スラリーを撹拌する装置を併せて設置すればより効果的であろう。ただ、この方法は、ガソリンスタンドや住宅の跡地の浄化といった比較的狭い土地を浄化するには使いにくいので、その際は後述するように「コンクリートミキサー車を改装した浄化機能付き移動車両」を活用した方が浄化の機動性は向上しよう。
【００１５】
また、地熱発電所、精錬所、原子力発電所、火力発電所、ゴミ等焼却場等の大量の熱を発生するプラントの高熱工業排水あるいは温泉水を用いて、請求項１〜５の方法を用いて浄化を行えるよう設計された省エネ型浄化プラントを活用できれば、熱源を節約する事はできるが、その分、汚染土壌等の輸送コストはかかる。そういった意味で、請求項１〜５の方法を行える設備一式（スラリー等を撹拌可能な装置、過酸化水素等酸化剤添加装置、生石灰等アルカリ剤添加装置、紫外線照射装置、触媒添加装置、加熱装置、加圧装置等）を設置し、原位置で石油等に汚染された土壌や海水等を浄化できるよう設計された移動車両・船舶プラントを建造するのが環境浄化を機動的に行う上で今後、重要になろう。そのためには、既存のコンクリートミキサー車、、タンクローリー車、油回収船等を請求項８に示した方法で改造してもよい。このようなプラントがあれば、例えば、ダイオキシンで汚染された土壌に、この改造ミキサー車を数台派遣し、数ヶ月かけてその場で分解を行わせた後に、そのまま車で走って、次の汚染場所に移る、といった浄化手法をとる事が可能となり、機動性を持たせた浄化が行える事が期待される。
【００１６】
なお、本発明では、特にプラント図等は用意しないが、要は、汚染土壌スラリーや汚染排水を撹拌槽に添加し、その撹拌槽に、生石灰、過酸化水素、触媒などをＩＣ制御等で投入する装置を設置し、その上でその撹拌槽自体をボイラー等で加温（もしくは加圧加温）する装置を付ければよく、また必要なら複数の反応槽に分ければ良いだけなので、わざわざ図面を引くに値しない程、単純であり、そして単純だからこそ組み合わせは多数考えられるが、請求項８の概念に入る限り、それら全てに特許請求を行いたい。
【００１７】
また、特に請求項１で示したアルカリ・過酸化水素法で浄化した場合は、生石灰、及び生石灰が水と反応した結果、生じる消石灰は、農業分野で一般に土壌改良材、若しくは肥料として用いられているので、処理土壌そのものを（酸性土壌に対する）土壌改良材、若しくは肥料として用いる事も可能である。実際、（実施例ではデータを示さなかったが）発明者らは本方法で浄化した土壌を用いて、コマツナを用いた発芽試験を３週間行ったが、順調な発芽及び植物生育が確認できた。これは残存した消石灰や石油成分分解物が植物の栄養源になるためと考えられる。また、その場合、仮に処理土壌に若干の過酸化水素が残存していても植物や植物根圏微生物群の多くは過酸化水素を分解する酵素（ＳＯＤ）を産生するので、特に問題とならず、逆に残存成分を除去する上でも緑化を行った方が効果的であるものと考えられる。なお、この技術は汚染地の緑化技術として使えると共に、植物自身あるいは植物の根に自然と（ゆるやかに）共生する土壌微生物群がラッカーゼ等を分泌し、残存している油状物質を分解する植物環境修復、微生物環境修復（ハイブリッド浄化技術）としても利用できる（ハイブリッド浄化）。なお、ここで用いる植物種は、浄化対照となる汚染物質によって選択すればよい。例えば、ダイオキシンの場合は、ラッカーゼ活性が高い漆が効果的に分解する事が出光興産株式会社らにより報告されている（塩素化ダイオキシン汚染土壌または水の浄化法、特開２００１−２３２３４５）。また、この汚染土壌地で栽培した植物に油状汚染物が一定割合で蓄積する可能性も考えられるので、その際は、重金属蓄積植物を用いた植物環境修復技術のように、その栽培植物が成長後、刈り取り、産業廃棄物として処理する方法も有効であろう。また、植栽を行う上で、生石灰処理でアルカリ化した土壌等に、ピートモス等の酸性土壌改良材や堆肥を添加し中性化を早めても良いし、好アルカリ性植物を植栽してもよい。更に、請求項１〜７の方法で浄化した土壌等では土着菌の多くが死滅しているので、外来性の微生物が定着しやすくなる効果も期待される事もあり、植栽を行わずに単に有害物質分解微生物群を添加したり、各種堆肥を添加したりする微生物環境修復技術を組み合わせたハイブリッド浄化法も有効である。
【００１８】
なお、本処理土壌を植物栽培に用いる場合は、できれば、食用にしない花卉栽培、観葉植物栽培、林業、造園等に用いた方が良いだろう。万一、有害な有機物質が植物に若干、蓄積しても、人体には影響しにくいからである。また、花卉、観葉植物、木材等は換金できるので、うまく農業経営すれば浄化コストの一部を回収できる効果が期待される。
【００１９】
次に、実施例にて本発明をより詳細に説明するが、本発明は下記の例のみに限定されるものではない。本実施例では、石油精製に用いられ廃棄物処理が求められている石油汚染白土をモデル浄化実験に用いた。本汚染白土は、油分が１０％近くあり、微生物が生育できないためバイオレメディエーション法は利用できない。また、油分が多すぎるため光分解処理も有効に機能しない。この厄介な石油汚染白土をわずか２時間程度で油臭及び着色油膜が十分に少ない水準まで浄化できる事を確認できたので以下に詳細に説明する。
【００２０】
【実施例】
この汚染白土をまず篩い（２ｍｍ）にかける事を試みたが、粘度が高く、篩いにかけるのは不可能だった。従って、この汚染白土を１ｋｇ秤量し、均質になるよう（ビニール手袋を付けた）手でこねて十分、混合した。５００ｍｌ共栓三角フラスコ１５本にそれぞれ５０ｇずつ加え、以下の５区に分け、それぞれ３連で実験を行った。（１）石油汚染土壌５０ｇに生石灰（和光一級、０３７−００７７５、和光純薬株式会社）５ｇ、過酸化水素水（試薬特級、３０％、和光純薬株式会社）５０ｍｌ．、超純粋５０ｍｌを加え、８０℃、２時間の条件で振とう処理した区。（２）石油汚染土壌５０ｇに生石灰（和光一級、０３７−００７７５、和光純薬株式会社）５ｇ、硫酸鉄（ＩＩ）七水和物（試薬特級、和光純薬株式会社）１ｇ．、過酸化水素水（試薬特級、３０％、和光純薬株式会社）５０ｍｌ．、超純粋５０ｍｌを加え、８０℃、２時間の条件で振とう処理した区。（３）石油汚染土壌５０ｇに生石灰（和光一級、０３７−００７７５、和光純薬株式会社）５ｇ、硫化鉄（ＩＩ）（試薬特級、関東化学株式会社）１ｇ．、過酸化水素水（試薬特級、３０％、和光純薬株式会社）５０ｍｌ．、超純粋５０ｍｌを加え、８０℃、２時間の条件で振とう処理した区。（４）石油汚染土壌５０ｇに生石灰（和光一級、０３７−００７７５、和光純薬株式会社）５ｇ、過酸化水素水（試薬特級、３０％、和光純薬株式会社）５０ｍｌ．、超純粋５０ｍｌを加え、８０℃、２時間の条件で振とう処理した区。（５）石油汚染土壌５０ｇに超純粋１００ｍｌを加え、８０℃、２時間の条件で振とう処理した区。
【００２１】
２時間の８０℃処理後、それぞれの三角フラスコの内容物をビーカーに移し、１時間放置後、油臭を確認した。油臭は、２名の臭気判定人により、６段階臭気強度表示法（０：無臭、１：やっと感知できる臭い、２：何の臭いであるかわかる弱い臭い、３：楽に感知できる臭い、４：強い臭い、５：強烈な臭い）を用いて盲目試験を行う事によって判定した。その結果、単に汚染土壌に水を加えた区（５）は、６段階中、最も強い「強烈な臭い」であるのに対し、生石灰と過酸化水素の双方を添加した区（１）に関しては、「何の臭いであるかわかる弱い臭い」まで分解できている事が確認できた。また、フェントン反応を行った（２）及び（３）に関しては、生石灰・過酸化水素法と比べれば、やや分解が劣る「楽に感知できる臭い」まで分解が進んでいた（（２）と（３）の差は区別付かず）。最後に、過酸化水素のみ添加した（４）に関しては、更に分解が進んでおらず「強い臭い」に留まっていた。従って、コンティニュアムエンバイロンメンタルインコーポレーテッドの出願特許「有機汚染物質の処理方法（特表２００１−５１３０２１）」の方法、すなわち過酸化水素のみ添加し熱処理する方法では、今回の汚染白土の浄化には太刀打ちできない事が明らかとなった。
【００２２】
次に、この５区を遠心管に移し、３０分間、室温で激しく振とうした後、８０００ｒｐｍで３０分遠心し、試験管の上層における油膜の形成を確認した。その結果、単に汚染土壌に水を加えた区（５）に関しては、５ｍｌ程度の真っ黒な油膜が確認でき、過酸化水素のみを添加した区（４）に関しても２ｍｌ程度の真っ黒な油膜が確認できたが、フェントン反応を行った（２）及び（３）に関しては黒い油膜が０．５ｍｌ程度と大幅に減少していた（（２）と（３）の差は区別付かず）。また、生石灰・過酸化水素法を適用した（１）に関しては着色した油膜は全く確認できなかったが、白い油膜が０．５ｍｌ程度、確認できる程度まで顕著に分解が進んでいる事が確認できた。
【００２３】
以上の結果により、生石灰・過酸化水素法を用いる事によって、フェントン反応法や、単に過酸化水素を添加し熱処理する区と比べると格段に石油分解が進んでいる事が実証できたものと考えられる。また、ここではデータを示さないが、乾燥オーブンで各処理土壌を乾燥させた後、ヘキサン抽出したヘキサン抽出液のＯＤ６００も測定したが、上の傾向と矛盾しない結果が得られた。なお、本実験では簡易法として油臭と油膜で油分の分解を確認したが、可能なら更にＧＣ−ＦＩＤ法等でより客観的な数値を取得する必要がある。しかし、論理さえしっかりしていれば特許が認められる制度となっている日本においては十分の実証データになっているものと考えられる。ＧＣ−ＦＩＤ法を含めた詳細な結果は追って学術誌に投稿したい。また、ここではデータを示さないが、８０℃２時間の熱処理の代わりに、オートクレーブ（１２７℃、２時間）を行う実験も行ったが、この場合は、更に分解が進んでいる事が確認できた。
【００２４】
【発明の効果】
実施例で示したように、生石灰及び過酸化水素添加と加圧加熱処理を組み合わせたアルカリ・過酸化水素法か、若しくはフェントン反応法のいずれかを適用する事によって、油分を高濃度に含んだ白土を短時間かつ安価に浄化できる。また、本発明で示した移動車両・船舶プラントを活用する事によって、日本全国の油汚染土壌及び油汚染海水を機動的に浄化できる事が期待される。更に、特に生石灰を用いたアルカリ・過酸化水素法を用いれば、処理後の土壌を用意に緑化する事が可能となり、ひいては、国民の健康と福祉に貢献する事ができるであろう。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to (1) an early purification method for petroleum contaminated soil and the like, (2) a greening method, and (3) a plant design method for performing the method.
[0002]
[Prior art]
Conventional methods for treating petroleum-contaminated soil include (1) microbial decomposition, (2) compost addition, (3) pyrolysis with electrodes, (4) solvent washing, (5) magnetic separation, and (6) magnetic separation. ) Heat separation method, (7) incineration method, (8) UV irradiation method and the like. However, among these purification methods, contaminated soil 1 m 3 per treatment method requires only 20,000 yen or less expenses is limited to 2,3. Among them, the biodegradation method is practically unusable for oily soils because the growth activity of the decomposed microorganisms is inhibited. Also, in the light irradiation method, since the soil slurry hardly transmits light, it is actually difficult to effectively irradiate a large amount of soil at the site, regardless of the laboratory level. Also, the method of volatilizing or burning the oil at several hundred degrees Celsius cannot ignore the danger of releasing harmful substances such as dioxin into the atmosphere. Further, regarding the solvent extraction method, not only do not consider reusing the soil after the treatment, but also there remains a problem that the plant cannot be assembled on site if the area is small, such as a gas station site. The present invention has been made in view of these points, (1) Oil contaminated soil 1 m 3 per performed at 20,000 yen or less expenses, are possible purification in (2) short term, (3 5) Reagents (quick lime, hydrogen peroxide, etc.) have relatively few problems, (4) they do not use large energy such as 300 ° C or more, and (5) they can use the soil after treatment for greening. It is considered that it has certain competitiveness compared with the conventional technology.
[0003]
The purification principle of the present invention can be roughly classified into the alkali-hydrogen peroxide method described in claim 1 and the Fenton reaction method described in claim 3. First of all, as a related patent relating to the former, it is necessary to mention “method of treating organic pollutants (Japanese Patent Application Publication No. 2001-513021)” of Continuum Environmental Inc., a US company. However, the US company's method is fundamentally different from the present invention in that “an alkali agent such as quick lime is not added”. When the oxidation treatment of the oil-contaminated soil is performed by adding only hydrogen peroxide as shown in the embodiment of the present invention, the oily substance is markedly oily as compared with the section accompanied by the addition of quicklime (which also acts as a saponifying agent). Degradation ability is inferior, especially when the proportion of oil is large, it cannot be sufficiently purified and cannot be used for greening. In this patent, all rights are limited to the "moving the soil from the processing apparatus to the processing apparatus" using the "continuous and independent processing apparatus connected by pipe means" in claim 1. According to the present invention, since the purification can be performed by a "single processing tank" without using "a continuous and independent processing apparatus connected by a pipe means" in the present invention, the U.S. Patent No. Can be determined not to conflict with.
[0004]
Regarding a related patent relating to claim 3 (that is, purification using the Fenton reaction), “Method for decomposing dioxins in solid (JP-A-2000-197867)” by Ebara Corporation is mentioned. However, the subject is limited to dioxin to the last, and the scope of claims is not limited to petroleum-contaminated soil and the like, and the iron compound used is also limited to ferrous sulfate. In contrast, in the present invention, the Fenton reaction was applied to the purification of soil contaminated with petroleum, and good results were obtained.Therefore, the Fenton reaction as a new technology applicable to the purification of soil contaminated with all organic compounds other than dioxin was obtained. Claims. Further, the iron compound used in the Fenton reaction is not limited to ferrous sulfate, but differs in that all iron compounds that supply divalent iron ions, such as iron sulfide, are charged. In addition, as a similar patent, it is necessary to mention “treatment method for dibenzo-p-dioxin and dibenzofuran” (Japanese Patent Application Laid-Open No. 2001-240596) filed by Fukuzo Todo, but this patent also claims only dioxins. It is excluded from being applicable to organic compounds other than dioxin such as oil-contaminated soil, and does not compete with claim 3 of the present invention as long as it purifies substances other than dioxin. Furthermore, it does not mention that iron sulfide, iron oxide, volcanic ash containing it, or iron and steel slag is particularly effective as a source of divalent iron ions. And rights are deemable.
[0005]
In addition, the present invention claims not only the principle of the method for purifying the soil contaminated with petroleum, but also a plant for performing the method (claims 6 to 9). Among them, as a related patent for the method utilizing the Joule heat shown in claim 6, it is necessary to mention "Method of Purifying Contaminated Soil" (JP-A-2002-1299) by Mazumi Co., Ltd. Since only a conductive substance is added and heated, even if trichlorethylene, which is relatively easy to decompose, can be decomposed, effective purification of petroleum-contaminated soil cannot be expected. A similar plant is also installed in the melt solidification method and the alkali catalytic chemical decomposition method, but both require a high temperature of 300 ° C. or more and the equipment becomes large, whereas the plant of the present invention has a temperature of 100 ° C. or less. Since it operates at a relatively low temperature, there is an advantage that the initial cost is low.
[0006]
Further, as a related patent relating to the energy-saving plant described in claim 7, "Incineration ash processing method and apparatus (Japanese Patent Application Laid-Open No. 2001-137803)" by Mitsubishi Heavy Industries, Ltd. needs to be mentioned. It is limited to contaminated fly ash only, and does not cover soil, sediment other than fly ash, or organic matter contamination other than dioxin such as petroleum. In addition, only wastewater from incinerators is limited, and natural energy such as geothermal power plants and hot springs, and wastewater from factories such as nuclear power plants and smelters are not targeted, and a sufficient energy saving effect cannot be expected.
[0007]
Finally, with respect to the mobile vehicle / ship plant having the purifying ability described in the eighth and ninth aspects, the inventors do not know what should be noted in the prior art. For example, even though many oil recovery vessels have been built, there are currently no vessels that can perform purification at the same time, so that waste transportation costs are high and the amount of oil recovery is greatly restricted. Therefore, it is expected that the present invention (claims 8 and 9) can improve the mobility of environmental purification. Further, there has not been reported any conventional technology of the concept of using soil, which has been partially purified, as described in claim 10 for revegetation. In particular, in the present invention, quick lime or the like is used for soil purification in claim 1, but quick lime or slaked lime is generally used in agriculture as a soil improvement material or fertilizer, and quick lime, slaked lime, etc. remaining in this purification treatment are used. The present invention will be the first to show the direction of using cracked petroleum components as a plant nutrient source.
[0008]
[Problems to be solved by the invention]
(1) A method of purifying petroleum-contaminated soil in a low-cost, prompt and environmentally-friendly manner, (2) A method of greening using purified soil, (3) Performing the above two treatments To provide a plant design method.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, water is added to petroleum-based contaminated soil to form a slurry, and then the addition of an alkali agent such as quicklime, the addition of hydrogen peroxide, and the heating and pressurizing treatment may be combined. Alternatively, an iron compound capable of supplying divalent iron ions such as iron sulfide and ferrous sulfate to the soil slurry, or a volcanic ash containing them and a Fenton reaction combining iron and steel slag and hydrogen peroxide may be used. Further, if necessary, (1) ozone, light irradiation, various oxidation treatments such as hypochlorous acid, (2) catalyst, (3) aeration or stirring, (4) addition of a carbonized material such as activated carbon, for a total of four treatments. If one or a plurality of them are combined, the resolution can be further promoted. In addition, when performing a heating treatment of the soil or the like (normal temperature to 100 ° C.), after putting the contaminated soil or the like in a slurry into a container installed in the ground or the like, an electrode is installed and Joule heat generated by energization is reduced. A plant designed to be used may be used. Further, the method according to claims 1 to 5, using high-heat industrial wastewater or hot spring water of a plant that generates a large amount of heat, such as a geothermal power plant, a smelter, a nuclear power plant, a thermal power plant, and a refuse incineration plant. A set of equipment capable of installing an energy-saving type purification plant designed to perform purification by means of purification, a device capable of stirring the slurry or the like, a device for adding an oxidizing agent such as hydrogen peroxide, a device for adding an oxidizing agent such as hydrogen peroxide, and an alkaline agent such as quicklime. Addition equipment, ultraviolet irradiation equipment, catalyst addition equipment, heating equipment, pressurization equipment, etc.) are installed, and mobile vehicles and marine plants designed to purify in-situ soil and seawater contaminated with oil etc. are used. Is also effective. Furthermore, plant environmental restoration method or greening method characterized by planting in partially purified soil etc. using these methods, and harmful substance degrading microorganisms group without simply planting in the soil etc. It is expected that the microbial environment restoration method using compost will also work effectively. In addition, the treatment of oil-contaminated soil using these methods can be used as a soil conditioner for correcting acid soil or as a fertilizer for flower cultivation, forestry, etc. It is valid.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in more detail. (1) addition of an alkali agent such as quicklime, (2) addition of hydrogen peroxide, and (3) heating treatment in the range of room temperature to 100 ° C (preferably around 80 ° C) to wastewater containing an organic substance, or What is necessary is just to combine a total of three processes of pressurization heating process (-200 degreeC). At this time, in the case of simply heating without applying pressure, it is better to perform stirring or aeration. By itself, the resolution of petroleum is remarkably improved in comparison with only quick lime treatment, only hydrogen peroxide treatment, or quick lime and hydrogen peroxide treatment only at normal temperature. In this case, the addition ratio of quick lime may be appropriately adjusted to approximately 30 to 30% of the weight of the oil-contaminated soil, and the addition ratio of hydrogen peroxide may be appropriately adjusted to approximately 5 to 30% of the weight of the oil-contaminated soil. The greater the amount of hydrogen peroxide added, the higher the petroleum resolution, but the higher the cost, and the conditions should be examined with cost-effectiveness in mind. According to the principle of this reaction, it can be assumed that the generation of hydroxyl radicals generated by the addition of hydrogen peroxide increases under alkaline conditions and high temperature conditions, and that oils containing ester bonds also have a saponification effect. In addition, the use of quicklime as an alkali agent here is expected to have an effect of reacting with water or carbon dioxide in the air and neutralizing naturally into calcium carbonate through slaked lime even in a strongly alkaline state. At the same time, it can be used as a heat source. In addition, quick lime, like hydrogen peroxide, is inexpensive, and processing costs can be kept low. The addition of these alkaline agents and hydrogen peroxide is not performed at once, but it is better to repeat the addition at regular time intervals in order to increase the generation efficiency of hydroxy radicals and heat generation throughout the entire operation time. desirable. Note that sodium hydroxide or the like may be used instead of quicklime, but in that case, it is necessary to neutralize with acetic acid, wood vinegar, or the like after the treatment. In carrying out these reactions, a simple heating treatment (normal temperature to 100 ° C.) may be used. However, if it is necessary to shorten the purification time even if it costs a little, the heating and pressurizing method (up to 200 ° C.) The effectiveness is clear from the pulp industry example. In fact, the inventors also compared the oil-contaminated soil treated at 127 ° C. for 2 hours with a normal high-pressure sterilizer (autoclave) and that treated at 80 ° C. for the same time. I have confirmed that
[0011]
In addition, it is not necessary to stick to the alkali / hydrogen peroxide method, and it is effective to use the Fenton reaction on petroleum-contaminated soil (although iron contamination is somewhat anxious). In this case, after adding water to the oil-based contaminated soil to form a slurry, (1) an iron compound capable of supplying divalent iron ions such as iron sulfide and ferrous sulfate, or a volcanic ash containing an iron compound, a steel slag, etc. And (2) hydrogen peroxide, and then, if necessary, heating under pressure (or only heating). In the case of dioxin, a patent has already been filed that the Fenton method works effectively.In this regard, the inventors can not claim, but this time, they tried the Fenton reaction method on petroleum contaminated soil. As a result, good purification was confirmed, and a new technology was claimed. Also,
As described in the section of the Related Art, the present inventors have found that iron sulfide is particularly effective among iron compounds, and claim that volcanic ash and the like containing the same can be used for soil purification. The points included will be the novelty of the present invention. In addition, iron slag is cited as a supply source of divalent iron ions, and it is considered that the point of including the effective use of steel slag can be claimed as uniqueness of the present invention. In the case of performing the Fenton reaction, it is expected that the decomposition proceeds more when the acid is applied at an acid pH of 6 or less.
[0012]
In order to further promote the petroleum cracking reaction, whether by the alkali-hydrogen peroxide method or the Fenton reaction method, means generally used in the accelerated oxidation reaction may be appropriately combined. Specifically, (1) ozone, light irradiation, various oxidation treatments such as hypochlorous acid, (2) catalyst, (3) aeration or stirring, (4) addition of carbonized material such as activated carbon, for a total of four treatments It is effective to combine one or more of them. However, care must be taken when treating soil or the like, since chlorine generated by hypochlorous acid treatment may be involved in the production of new harmful substances. In addition, if these processes are performed, the cost is increased accordingly. Therefore, it is better to purify with a system as simple as possible. In that sense, when purifying environmental contaminants, a method of adding quicklime and hydrogen peroxide and performing a heat treatment is considered to be the simplest and most effective method.
[0013]
The use of these methods not only purifies oil-contaminated soil, but also dioxins, PCBs, environmental hormones, residual pesticides, animal and vegetable oils, estrogen, residual chemical weapons in soil, sediment, food, kitchen wastewater, etc. It is also possible to remove various harmful organic substances and odorous substances, such as harmful organic substances in the environment and foods.
[0014]
If it is necessary to treat a large amount of contaminated soil such as petroleum on a large site, when heating the soil etc., put the contaminated soil in slurry into a container installed underground etc. If a plant designed to carry out the treatments of claims 1 to 5 with the electrodes installed and Joule heat (発 生 100 ° C.) generated by energization would be able to achieve the objective relatively inexpensively. At this time, it is necessary to install a simple off-gas hood so that the water does not evaporate to dryness. If possible, it would be more effective to install a device for stirring the soil slurry. However, it is difficult to use this method to clean relatively small land, such as gas stations and houses, so use a “mobile vehicle with a purification function that has been remodeled from a concrete mixer truck” as described later. This will improve the mobility of purification.
[0015]
Further, the method according to claims 1 to 5, using high-heat industrial wastewater or hot spring water of a plant that generates a large amount of heat, such as a geothermal power plant, a smelter, a nuclear power plant, a thermal power plant, and a refuse incineration plant. If an energy-saving purification plant designed to purify wastewater can be utilized, the heat source can be saved, but the transportation cost of contaminated soil and the like will increase accordingly. In that sense, a set of equipment capable of performing the method of claims 1 to 5 (a device capable of stirring a slurry or the like, a device for adding an oxidizing agent such as hydrogen peroxide, a device for adding an alkali agent such as quicklime, an ultraviolet irradiation device, a catalyst adding device, a heating device) , Pressurizing equipment, etc.) to build mobile vehicles and marine plants designed to purify in-situ soil and seawater contaminated with petroleum, etc. , Become important. For this purpose, existing concrete mixer trucks, tank trucks, oil recovery vessels, etc. may be modified by the method described in claim 8. If there is such a plant, for example, after sending several modified mixer trucks to soil contaminated with dioxin and let them decompose on the spot over several months, drive as it is, It is possible to take a purification method such as moving to a polluted place, and it is expected that purification with mobility can be performed.
[0016]
In the present invention, a plant diagram or the like is not particularly prepared, but the point is that a contaminated soil slurry or contaminated wastewater is added to a stirring tank, and quicklime, hydrogen peroxide, a catalyst, and the like are charged into the stirring tank by IC control or the like. It is only necessary to install a device that heats (or pressurizes and heats) the stirring tank itself with a boiler or the like, and if necessary, it is only necessary to divide it into multiple reaction tanks. It is simple enough to be worth it, and many combinations are conceivable because of its simplicity, but as long as it falls within the concept of claim 8, we would like to claim all of them.
[0017]
In particular, when purified by the alkali / hydrogen peroxide method as set forth in claim 1, quicklime and slaked lime produced as a result of the reaction of quicklime with water are generally used as soil improvement materials or fertilizers in the agricultural field. Therefore, the treated soil itself can be used as a soil conditioner (for acid soil) or as a fertilizer. In fact, although the data was not shown in the examples, the inventors performed a germination test using komatsuna for 3 weeks using the soil purified by this method, and confirmed that the germination and plant growth were successful. . This is thought to be because the remaining slaked lime and petroleum component decomposed products become nutrient sources for plants. Further, in this case, even if a small amount of hydrogen peroxide remains in the treated soil, many of the plants and plant rhizosphere microorganisms produce an enzyme (SOD) that decomposes hydrogen peroxide. On the contrary, it is considered that greening is more effective in removing residual components. This technology can be used as a greening technology for contaminated areas, and a plant environment in which soil microorganisms that coexist naturally (slowly) with the plant itself or plant roots secretes laccase and decomposes residual oily substances. It can also be used for restoration and microbial environment restoration (hybrid purification technology) (hybrid purification). The plant species used here may be selected according to the pollutant to be purified. For example, in the case of dioxin, it has been reported by Idemitsu Kosan Co., Ltd. that lacquer having a high laccase activity is effectively decomposed (a method for purifying chlorinated dioxin-contaminated soil or water, JP-A-2001-232345). It is also possible that a certain percentage of oily contaminants may accumulate on plants grown in this contaminated soil area. Later, harvesting and disposal as industrial waste would also be effective. In addition, in planting, soil neutralized by quick lime treatment, etc., may be added acid soil improver such as peat moss or compost to accelerate the neutralization, or even plant an alkalophilic plant Good. Furthermore, since many of the indigenous bacteria have died in the soil and the like purified by the method of claims 1 to 7, the effect that exogenous microorganisms can easily colonize is also expected, and without planting. A hybrid purification method combining microbial environment remediation techniques, such as simply adding harmful substance decomposing microorganisms or adding various composts, is also effective.
[0018]
When the treated soil is used for plant cultivation, it is better to use it for cultivation of non-edible flowers, houseplants, forestry, landscaping, etc., if possible. This is because even if a small amount of harmful organic substances accumulate in plants, it is unlikely to affect the human body. In addition, flowers, houseplants, wood, and the like can be cashed, and if farming is carried out well, the effect of recovering part of the purification cost is expected.
[0019]
Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to only the following examples. In this example, petroleum contaminated clay, which is used for petroleum refining and requires waste treatment, was used in a model purification experiment. This contaminated clay has an oil content of nearly 10% and cannot be used for bioremediation because microorganisms cannot grow. In addition, the photolysis treatment does not function effectively because the oil content is too large. It has been confirmed that this troublesome petroleum polluted clay can be purified to a sufficiently low level in oily odor and colored oil film in only about 2 hours, and will be described in detail below.
[0020]
【Example】
An attempt was first made to sieve (2 mm) the contaminated clay, but it was impossible to sieve because of high viscosity. Therefore, 1 kg of the contaminated clay was weighed, kneaded with a hand (with vinyl gloves) to homogeneity, and sufficiently mixed. 50 g was added to each of 15 500 ml stoppered Erlenmeyer flasks, divided into the following five sections, and the experiment was performed in triplicate. (1) 5 g of quicklime (Wako 1st grade, 037-00775, Wako Pure Chemical Industries, Ltd.) and 50 ml of hydrogen peroxide solution (special grade reagent, 30%, Wako Pure Chemical Industries, Ltd.) were added to 50 g of oil-contaminated soil. , 50 ml of ultrapure water and shaking at 80 ° C. for 2 hours. (2) 5 g of quicklime (Wako first grade, 037-00775, Wako Pure Chemical Industries, Ltd.) and 1 g of iron sulfate (II) heptahydrate (special grade reagent, Wako Pure Chemical Industries, Ltd.) in 50 g of petroleum contaminated soil. , 50 ml of aqueous hydrogen peroxide (reagent grade, 30%, Wako Pure Chemical Industries, Ltd.). , 50 ml of ultrapure water and shaking at 80 ° C. for 2 hours. (3) 5 g of quicklime (Wako first grade, 037-00775, Wako Pure Chemical Industries, Ltd.) and 1 g of iron (II) sulfide (special grade reagent, Kanto Chemical Co., Ltd.) in 50 g of oil-contaminated soil. , 50 ml of aqueous hydrogen peroxide (reagent grade, 30%, Wako Pure Chemical Industries, Ltd.). , 50 ml of ultrapure water and shaking at 80 ° C. for 2 hours. (4) 5 g of quicklime (Wako first grade, 037-00775, Wako Pure Chemical Industries, Ltd.) and 50 ml of hydrogen peroxide water (special grade reagent, 30%, Wako Pure Chemical Industries, Ltd.) were added to 50 g of oil-contaminated soil. , 50 ml of ultrapure water and shaking at 80 ° C. for 2 hours. (5) A section obtained by adding 100 ml of ultrapure to 50 g of petroleum-contaminated soil and shaking at 80 ° C. for 2 hours.
[0021]
After 2 hours of treatment at 80 ° C., the contents of each Erlenmeyer flask were transferred to a beaker, and after leaving for 1 hour, an oily odor was confirmed. The oily odor is evaluated by two odor determination persons in six levels of odor intensity display method (0: no odor, 1: odor that can be finally detected, 2: weak odor that shows what odor is, 3: odor that can be easily detected, 4 : Strong odor, 5: intense odor). As a result, the zone (5) in which water was simply added to the contaminated soil had the strongest “strong smell” among the six levels, whereas the zone (1) in which both quicklime and hydrogen peroxide were added had the highest intensity. , It was confirmed that the substance had been decomposed to "a weak smell which indicates what smell". In addition, as for (2) and (3) in which the Fenton reaction was performed, the decomposition progressed to an “easy-perceivable smell”, which is slightly inferior to that of the quick lime / hydrogen peroxide method ((2) and (3) ) Is indistinguishable). Finally, with respect to (4) to which only hydrogen peroxide was added, the decomposition was not progressed further and remained "strong odor". Therefore, according to the method of the application patent “Contamination method of organic contaminants (Japanese Patent Application Laid-Open No. 2001-513021)” of Continuum Environmental Inc., that is, the method of adding only hydrogen peroxide and performing heat treatment, the purification of the contaminated clay is not possible. It became clear that he could not compete.
[0022]
Next, the five sections were transferred to a centrifuge tube, vigorously shaken at room temperature for 30 minutes, and then centrifuged at 8000 rpm for 30 minutes to confirm the formation of an oil film in the upper layer of the test tube. As a result, in the section (5) where water was simply added to the contaminated soil, a black oil film of about 5 ml was confirmed, and in the section (4) where only hydrogen peroxide was added, a black oil film of about 2 ml was confirmed. However, in the cases of (2) and (3) where the Fenton reaction was performed, the black oil film was significantly reduced to about 0.5 ml (the difference between (2) and (3) cannot be distinguished). In the case of (1) to which the quicklime / hydrogen peroxide method was applied, no colored oil film could be confirmed at all, but it was confirmed that the decomposition of the white oil film was remarkably progressed to about 0.5 ml. Was.
[0023]
The above results suggest that the use of the quicklime / hydrogen peroxide method has demonstrated that petroleum cracking has progressed significantly compared to the Fenton reaction method and the section in which hydrogen peroxide is simply added and heat treated. Can be Although data is not shown here, the OD600 of the hexane extract obtained by drying each treated soil in a drying oven and then extracting with hexane was measured, but results consistent with the above tendency were obtained. In this experiment, the decomposition of oil was confirmed by the oil odor and the oil film as a simple method. However, if possible, it is necessary to obtain more objective numerical values by the GC-FID method or the like. However, in Japan, where the system is such that patents can be granted if the logic is firm, it is considered that the data is sufficient empirical data. Detailed results, including the GC-FID method, will be posted to journals later. Although data is not shown here, an experiment in which an autoclave (127 ° C., 2 hours) was performed instead of the heat treatment at 80 ° C. for 2 hours was also performed. In this case, it was confirmed that decomposition was further advanced. Was.
[0024]
【The invention's effect】
As shown in the examples, by adding either the quicklime and the hydrogen peroxide method combined with the addition of hydrogen peroxide and pressurized heat treatment, or the Fenton reaction method, the oil content was high. White clay can be purified in a short time and at low cost. In addition, it is expected that the use of the mobile vehicle / ship plant described in the present invention will allow the oil-contaminated soil and oil-contaminated seawater throughout Japan to be purified in a flexible manner. Furthermore, if the alkali / hydrogen peroxide method using quick lime is used, the soil after treatment can be easily greened, which will contribute to the health and welfare of the people.