JP4701588B2

JP4701588B2 - A treatment method for detoxifying a workpiece contaminated with an organic halogen compound

Info

Publication number: JP4701588B2
Application number: JP2003197764A
Authority: JP
Inventors: 要樹清水; 康行長井
Original assignee: Tosoh Corp
Current assignee: Tosoh Corp
Priority date: 2003-07-16
Filing date: 2003-07-16
Publication date: 2011-06-15
Anticipated expiration: 2023-07-16
Also published as: JP2005034696A

Description

【０００１】
【発明の属する技術分野】
本発明は、有機ハロゲン化合物で汚染された土壌、産業廃棄物、汚泥、スラッジ等の被処理物に対する無害化処理方法に関するものである。
【０００２】
【従来の技術】
世界各地でＴＣＥ（トリクロロエチレン）、ＰＣＥ（テトラクロロエチレン）、ＤＣＭ（ジクロロメタン）、ＰＣＢ（ポリ塩化ビフェニル）及びダイオキシン類等の有機ハロゲン化合物による環境汚染問題が顕在化し大きな問題となっている。
【０００３】
これらの問題に対し、特に揮発性有機ハロゲン化合物（ＶＯＣ）により汚染された土壌、排水、地下水等に対する無害化用処理剤およびその処理方法が検討され、いくつかの技術報告や特許出願がされている。
【０００４】
以下のような汚染土壌、スラッジ、汚泥等の処理法が知られている。
【０００５】
１）土壌中のＶＯＣガス吸引・活性炭吸着処理法があるが、ガス吸引周辺以外は処理できないため処理に長期間を要し、ＶＯＣを吸着した活性炭再生処理等を含めた処理費用が大きいことが問題である。
【０００６】
２）掘削土壌中または直接土壌中に加熱用電極を挿入し加熱処理する熱脱着法および熱分解法は、大掛かりな加熱装置が必要であり、電極近傍は熱分解されるが、その他の場所ではＶＯＣが揮散するだけで根本的な処理法では無い。
【０００７】
３）微生物を経由した還元物質により無害化処理するバイオレメデイエーション法は、無害化に長時間必要であり、しかも全種類の土壌に対応できず完全な無害化は不可能である。
【０００８】
最近、化学的処理として、
４）汚染土壌に鉄系処理剤を添加した還元処理法は、掘削土壌と鉄系処理剤を混合し地上にパイル（山）状に積み上げ養生処理する方法が開示されている（例えば、特許文献１参照）が、汚染物質と鉄粉の接触確率が低いと浄化に長時間が必要である。
【０００９】
鉄粉を圧縮空気又は水圧により汚染土壌に注入する方法が開示されている（例えば、特許文献２〜特許文献４参照）が、汚染土壌中の全領域に鉄粉を均一に注入することは困難と思われる。
【００１０】
鉄粉と一緒に給水剤を汚染土壌に添加する処理法が開示されている（例えば、特許文献５参照）が、給水剤と鉄粉の均一混合また無害化処理後の土壌強度対策が問題となる。
【００１１】
一方、５）酸化処理法として、鉄粉に酸化剤として過酸化水素水または過マンガン酸カリウムを添加する方法が開示されている（例えば、特許文献６〜特許文献８参照）が、鉄粉と酸化剤を均一混合するため、特殊な２軸以上の混合機を用い、セメント系土壌改質剤や砂の添加を必要とし、長時間混合が必要である。
【００１２】
【特許文献１】
特開２００１−０００５７７号公報
【特許文献２】
特開２００２−２００４７８号公報
【特許文献３】
特開２０００−１３５４８３号公報
【特許文献４】
特開２００１−０３８３４１号公報
【特許文献５】
特開２００２−１５９９６０号公報
【特許文献６】
特開２００１−２７６７９９号公報
【特許文献７】
特開２００２−３２６０８０号公報
【特許文献８】
特開２００３−８０２２３号公報
【００１３】
【発明が解決しようとする課題】
以上述べたように有機ハロゲン化合物で汚染された土壌、産業廃棄物、汚泥、スラッジ等に対する従来の処理法は各処理剤と被処理物との混合不足のため処理期間が長いこと、コスト高であること、処理法が複雑であること、該当する汚染物質の環境基準値をクリアできないことなどの課題を抱えている。特に汚染が局在化している場所では低コスト、低エネルギーで混合効率を高めることが必要である。
【００１４】
本発明の目的は、被処理物中の有機ハロゲン化合物を低コスト、均一混合法により対象有機ハロゲン化合物を短期間に該当する環境基準以下とする、有機ハロゲン化合物で汚染された土壌、産業廃棄物、汚泥、スラッジ等の被処理物に対する無害化処理方法を提供するものである。
【００１５】
【課題を解決するための手段】
本発明者は、前記目的を達成するために、ＶＯＣで汚染された被処理物を短時間に均一混合、特に液状化混合により無害化処理する方法について検討した。即ち、被処理物を液状化混合する処理方法により被処理物中のＶＯＣを環境基準以下にする方法である。さらにＦｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末および酸化剤を添加、液状化混合する方法により短時間に無害化処理でき、好ましくは液状化混合する際に液状化混合物のｐＨ範囲を調整する処理方法に特徴がある。
【００１６】
以下に、本発明について詳細に説明する。
【００１７】
本発明は、有機ハロゲン化合物で汚染された被処理物を無害化処理する方法において、被処理物を液状化混合することを特徴とする有機ハロゲン化合物で汚染された被処理物を無害化する処理方法、及び被処理物にＦｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末、又はＦｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末および酸化剤を添加し、被処理物を液状化混合することを特徴とする有機ハロゲン化合物で汚染された被処理物を無害化する処理方法に関するものである。
【００１８】
本発明の無害化処理方法において、無害化処理する被処理物は、有機ハロゲン化合物で汚染されたものであり、有機ハロゲン化合物の例としては、ＤＣＭ、四塩化炭素、クロロホルム、１，２−ジクロロエタン、１，１−ＤＣＥ（１，１−ジクロロエチレン）、Ｃｉｓ−ＤＣＥ（Ｃｉｓ−ジクロロエチレン）、Ｔｒａｎｓ−ＤＣＥ（ｔｒａｎｓ−１，２−ジクロロエチレン）、ＭＣ（１，１，１−トリクロロエタン）、１，１，２−トリクロロエタン、ＴＣＥ、ＰＣＥ、１，３−ジクロロプロペン等の有機塩素系化合物、またはこれらの有機臭素系化合物等が挙げられ、被処理物としては、土壌、産業廃棄物、汚泥、スラッジ等が挙げられる。
【００１９】
本発明の液状化とは、含水被処理物の粒同士がはなれて、水に浮いた状態となり、最終的には各粒子が沈んで、被処理物表面に水が出てくる状態のことをいう。外見上は混合時に被処理物自体が混合機内で自転している。
【００２０】
本発明の液状化混合方法として、１）振動機能を備えた混練機、混合機又は造粒機で行う方法、２）特に、振動機能を備えた混練機としては、例えば振動型ミキサ、バイブロミキサ、バイブロエクスプローラ又はロッド内蔵型外部円振動式混練機がある。また、被処理物にＦｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末、又はＦｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末および酸化剤を添加する場合には、３）連続式として、例えば振動機能を備えた土壌改良機等が用いられ、振動機能を備えた容器に、被処理物およびＦｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末、又は被処理物、Ｆｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末および酸化剤を該容器供給口から連続的に供給して液状化混合する方法、４）汚染土壌を直接無害化処理する原位置処理法においては、有機ハロゲン化合物で汚染された被処理物の表面に穴を掘削し、該穴中に振動機能を備えた鋼鈑、棒、ドリル又はスクリュー、さらにＦｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末、又はＦｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末および酸化剤を挿入して液状化混合処理することができる。
【００２１】
また、液状化混合時間は小規模混合機における混合時間より規定でき、土壌の透水係数や含水量等の物性から振動混合条件（振動出力等）を見積もれば、より効率的な混合が可能となる。
【００２２】
次に被処理物にＦｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末、該酸化剤を添加・液状化混合する方法としては、有機ハロゲン化合物で汚染された被処理物にＦｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末のみを添加・混合する方法、Ｆｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末および該酸化剤を同時に添加し混合する方法、またはＦｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末を添加し混合後、該酸化剤を添加し混合する方法を採用することができる。
【００２３】
これらの添加・混合方法において重要なことは、混合時の液状化混合物のｐＨを調整することであって、これにより短期間に、かつ確実に無害化できる。ｐＨ範囲は７未満が好ましく、更にｐＨ１以上が好ましい。混合物のｐＨが７以上では分解能を著しく低下させる。また混合物のｐＨが１未満では水素発生が起こり金属系処理剤による分解効率が低下する。またｐＨ調整時期は、Ｆｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末添加時の前後、該酸化剤添加時の前後に行なうことができる。
【００２４】
ｐＨの調整はｐＨ調整剤を用いて行う。ｐＨ調整剤としては、無機酸、例えば硫酸、リン酸、塩酸、硝酸、蓚酸、フタル酸塩等が挙げられるが、その内、硫酸、リン酸、塩酸より選ばれる少なくとも１種類を使用してｐＨを調整することが好ましい。
【００２５】
Ｆｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末および該酸化剤の添加量は、液状化混合時間、混合機の振幅、被処理物の汚染濃度等により変動するが、本発明の液状化混合が非常に優れた均質混合であることから、従来剤に比較し、少ない添加量で環境基準値未満への浄化が達成できる。本発明のＦｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末の添加量は、その分解活性及び経済性を考慮すると、湿体土壌等の被処理物に対して０．１〜１０重量％、特に１〜５重量％であることが好ましい。また、酸化剤の添加量は、Ｆｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末の添加量、土壌水分、混合方法等により異なるが、被処理物に対して０．１〜２０重量％、特に０．５〜１０重量％であることが好ましい。
【００２６】
本発明で用いる金属系処理剤としてはＦｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末を用いる。さらに望ましくは該Ｆｅ粉末とＮｉ粉末からなる混合物を、機械的合金化法とも呼ばれているメカニカルアロイング（ＭＡ）法により得た合金粉末または部分合金粉末を用いることができる。特にＦｅ成分に対するＮｉ成分の混合量及び混合状態、すなわち最適な合金化、部分合金化状態とすることが必要である。具体的には、該Ｆｅ粉末１００重量部に対しＮｉ粉末を０．０１〜２重量部、好ましくは０．１〜０．５重量部、更に好ましくは０．１〜０．３重量部混合させる。この範囲において驚くべきことに被処理物の還元分解能は著しく向上する。Ｎｉ粉末が０．０１重量部未満では有機ハロゲン化合物の分解能は低下し、Ｎｉ粉末無添加であるＦｅ粉末のみの分解能と同程度となり、分解能が不十分である。Ｎｉ粉末２重量部を超えても分解能はこれ以上高くはならず、ＮｉがＦｅと比較して高価な為、コストの面で相当不利となる。
【００２７】
また、本発明でＭＡ法に用いるＮｉ粉末は純Ｎｉ粉末、工業用Ｎｉ粉末の他にフェロニッケル粉末等が含まれる。一般的に入手可能な工業用Ｎｉ紛末は１０〜１００μｍの粒径を有しており、更には、１〜１０μｍ程度の微粒Ｎｉ紛末も好適に使用可能である。
【００２８】
以下に、本発明のＭＡ法による金属系処理剤の製造方法について説明する。
【００２９】
前記のＦｅ粉末およびＮｉ粉末を所定の組成に調整し、一般的なボールミル、Ｖミキサー等により混合し均質化する。また、場合によっては、ＭＡ法装置に定量供給機等を採用して、混合工程を省くことも可能である。ＭＡ法に使用する装置としては、一例としてアトライターミル（攪拌ボールミル、アトリッションミルとも呼ばれる）、振動ミル、回転ミル（メカノフユージョン含む）のバッチ式または連続式粉砕機を使用する。加工条件は、使用する装置により異なり一義的に定められないが、通常各装置の仕様条件の範囲内で採用できる。これらの装置の中で加工時間を最小とすることができるアトライターミルが特に好ましく、その加工条件としては、Ｆｅ粉末とＮｉ粉末の混合物１重量部に対して、鋼球等の粉砕メディアを７〜１５倍仕込む。原料が加工中に空気酸化する恐れがある場合は窒素ガス等の不活性ガスを流すことができる。ミル回転数は２００〜８００ｒｐｍが好適である。加工時間は、特に制限されないが、０．５〜５０時間が高い分解活性を発現できるため好ましい。加工時間を０．５〜６時間とした場合には、Ｆｅ粉末内および表面にＮｉ成分が偏析した部分合金となり、高い活性を得ることができ特に好ましい。
【００３０】
Ｆｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末の形状は特に限定するものではなく、球形状、樹枝状、片状、針状、角状、積層状、ロッド状、板状、海綿状等が含まれる。
【００３１】
Ｆｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末の比表面積は０．０５ｍ^２／ｇ以上、特に０．２〜１０ｍ^２／ｇが好ましい。
【００３２】
Ｆｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末の粒径は、２００μｍのふるいを通過する粒径、望ましくは３０〜１００μｍを用いることにより、分解反応速度を向上することが出来る。特に比表面積が０．２ｍ^２／ｇ以上、粒径７５μｍ以下の金属系処理剤を使用すれば難分解性であるＣｉｓ−ＤＣＥ、ＭＣ、ＰＣＥも、より短時間に分解できるので望ましい。
【００３３】
次に、本発明で使用する酸化剤としてはオゾン、次亜塩素酸ナトリウム、さらし粉、酸化亜鉛、酸化チタン、過酸化水素、過硫酸塩、過マンガン酸塩、ヒドロキシルラジカルが挙げられるが、その内、過酸化水素、過硫酸塩、過マンガン酸塩、ヒドロキシルラジカルより選ばれる少なくとも１種類が好ましく、これらを溶液中に含ませて添加することが好ましい。これらの中で、過硫酸塩、過酸化水素は水溶液で容易に取り扱うことができる為、特に好ましい。
【００３４】
また、Ｆｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末や該酸化剤の性能を低下させること無く、さらに均一混合を促進する剤として、ドデシル硫酸ナトリウムやトリトン−Ｘ等の界面活性剤、炭酸アンモニウムや炭酸水素ナトリウム等の発泡剤を併用することができる。
【００３５】
【実施例】
次に、本発明を実施例によりさらに具体的に説明するが、本発明はこれらの実施例によって何等限定されるものではない。
【００３６】
実施例では、液状化混合機として阿部鐵工所製バイブロエクスプローラ、ＶＭＹＣ−２５型（７３０ｒｐｍ）、図１を用いた。また、比較用混合機として北川鉄工所製ダブルミキサーＷＡ型（１６ｒｐｍ）、図２を用いた。
【００３７】
金属系処理剤に用いるＦｅ粉末として（同和鉱業製、商品名Ｅ２００）、ＭＡ法に用いる原料鉄粉として還元鉄粉（川崎製鉄（株）製、商品名ＫＩＰ−１００Ｔ）また原料Ｎｉ粉としては添川理化学社製Ｎｉ粉（純度９９％、粒径２〜３μｍグレード品）を用いた。
【００３８】
比較例１
ＶＯＣとして０．２５ｐｐｍ−ＰＣＥ、０．３５ｐｐｍ−ＴＣＥ及び０．３５ｐｐｍ−Ｃｉｓ−ＤＣＥを含有する粘土質汚染土壌の無害化処理を行なった。処理方法としては該汚染土壌１５０ｋｇ（含水率３０重量％）を５ｃｍ金網でふるい、該通過土壌をバイブロエクスプローラ混合機により２０分間混合した。混合時のｐＨは６．４であった。このようにして得られた処理土壌を１２５ｍｌバイアルビンに３０ｇ挿入し、密閉した。
【００３９】
バイブロエクスプローラ混合機の混合条件は該混合機に鉄製ロッドφ１００ｍｍを３本内蔵させ、７３０ｒｐｍ円振動荷重、両振幅１０ｍｍに設定した。
【００４０】
比較例２
ＶＯＣとして０．２３ｐｐｍ−ＰＣＥ、０．３０ｐｐｍ−ＴＣＥ及び０．３０ｐｐｍ−Ｃｉｓ−ＤＣＥを含有する粘土質汚染土壌の無害化処理を行なった。混合時のｐＨは７．５であった。その他の処理条件は比較例１と同様である。
【００４１】
比較例３
ＶＯＣとして０．２０ｐｐｍ−ＰＣＥ、０．２８ｐｐｍ−ＴＣＥ及び０．２０ｐｐｍ−Ｃｉｓ−ＤＣＥを含有する粘土質汚染土壌の無害化処理を行なった。混合時のｐＨは８．２であった。その他の処理条件は比較例１と同様である。
【００４２】
比較例４
比較例１の汚染土壌を用い、混錬機としてダブルミキサー（ニ軸ミキサー）ＷＡ型（１６ｒｐｍ）を使用する以外は比較例１と同じ処理条件により操作した。混合時のｐＨは６．６であった。
【００４３】
比較例５
比較例２の汚染土壌を用い、混錬機としてダブルミキサー（ニ軸ミキサー）ＷＡ型（１６ｒｐｍ）を使用する以外は比較例２と同じ処理条件により操作した。混合時のｐＨは７．６であった。
【００４４】
比較例６
比較例３の汚染土壌を用い、混錬機としてダブルミキサー（ニ軸ミキサー）ＷＡ型（１６ｒｐｍ）を使用する以外は比較例３と同じ処理条件により操作した。混合時のｐＨは８．６であった。
【００４５】
各ＶＯＣ濃度の分析方法としては、環境省告示第１８号記載のＪＩＳＫ０１２５（用水、排水中の揮発性有機化合物試験方法）に基づいたヘッドスペース法を用い、ＶＯＣ濃度を経時的に定量分析した。また、比較例１〜３及び比較例４〜６のＶＯＣ濃度が環境基準値（ＰＣＥ：０．０１ｐｐｍ、ＴＣＥ：０．０３ｐｐｍ、ｃｉｓ−ＤＣＥ：０．０４ｐｐｍ）未満になった分解日数を求め、これらの結果を表１に示し、汚染土壌中の各ＶＯＣ濃度の経時変化を図３（比較例１〜３、比較例４〜６）に示した。
【００４６】
【表１】

比較例１〜３は混合を始めると該汚染土壌が液状化し混合機の中で土壌自体が自転していることを確認している。表１及び図３から分かるように、９０日後には環境基準以下となった。表１には示していないが、分解副生物として環境基準対象物が生成していないことを確認している。
【００４７】
比較例４〜６はニ軸ミキサーによる混合処理によるものであるが、被処理物の液状化現象は認められず固形物として混合されていた。２０分間混合後は若干、各ＶＯＣ濃度は減少する傾向にはあるが、９０日後も各ＶＯＣ濃度は環境基準をクリアすることができなかった。
【００４９】
実施例１〜７、比較例７〜９
ＶＯＣとして４．５ｐｐｍ−ＰＣＥ、３．０ｐｐｍ−ＴＣＥ及び３．１ｐｐｍ−Ｃｉｓ−ＤＣＥを含有する粘土質汚染土壌（ｐＨ６．８）の無害化処理を行なった。処理方法としては該汚染土壌１５０ｋｇ（含水率２８重量％）を５ｃｍ金網でふるい、該通過土壌に表２に示す金属系処理剤としてＭＡ加工したＦｅ−０．３重量％Ｎｉ（ＭＡ剤）、または鉄粉を対汚染土壌１重量％（１．５ｋｇ）添加、酸化剤として３５％過酸化水素水を対汚染土壌３重量％添加、ｐＨ調整剤として１／３Ｍ−硫酸を添加し、バイブロエクスプローラ混合機により４分間混合した。
【００５０】
このようにして得られた処理土壌を１２５ｍｌバイアルビンに３０ｇ挿入し、密閉した。
【００５１】
バイブロエクスプローラ混合機の混合条件は該混合機に鉄製ロッドφ１００ｍｍを３本内蔵させ、７３０ｒｐｍ円振動荷重、両振幅１０ｍｍに設定した。
【００５２】
実施例１〜５、６〜７において用いた金属系処理剤（ＭＡ剤）の製造条件を以下に示す。
【００５３】
還元鉄粉（川崎製鉄製ＫＩＰ−１００Ｔ）および０．３重量部（対鉄粉１００重量部）のＮｉ粉（添川理化学社製）からなる原料１ｋｇをボールミルで１０分間混合後、５Ｌポットを有するアトライターミル（三井鉱山（株）製、商品名ＤＹＮＡＭＩＣＭＩＬＬ、ＭＡ１Ｄ型）内に鋼球（ＳＵＪ２）７．５ｋｇと一緒に仕込み、ＭＡ加工した。この際の窒素ガス流量は４０ｍｌ／分とした。ＭＡ加工条件として加工１時間、回転数は４００ｒｐｍとした。
【００５４】
比較例８において用いた鉄粉は同和鉱業製Ｅ２００である。
【００５５】
尚、今回用いた金属系処理剤の比表面積は０．２５ｍ²／ｇ、７５μｍのふるいを通過した粉末を用いた。
【００５６】
比較例７は汚染土壌に１／３Ｍ−硫酸溶液によりｐＨを６．３に調整後、バイブロエクスプローラ混合機で４分間混合した。
【００５７】
実施例１は汚染土壌に金属系処理剤（ＭＡ剤）を１重量％添加、１／３Ｍ−硫酸溶液によりｐＨを５．１に調整後、バイブロエクスプローラ混合機で４分間混合した。
【００５８】
実施例２は汚染土壌に金属系処理剤（ＭＡ剤）を１重量％添加、バイブロエクスプローラ混合機で４分間混合後、１０日後に酸化剤として３５％過酸化水素水を３重量％添加、再びバイブロエクスプローラ混合機で４分間混合した。混合時のｐＨを６．３であった。
【００５９】
実施例３は、汚染土壌に金属系処理剤（ＭＡ剤）を１重量％添加、１／３Ｍ−硫酸溶液によりｐＨを５．５に調整後、バイブロエクスプローラ混合機で４分間混合後、１０日後に酸化剤として３５％過酸化水素水を３重量％添加、再びバイブロエクスプローラ混合機で４分間混合した。混合時のｐＨは５．５であった。
【００６０】
実施例４は、汚染土壌に金属系処理剤（ＭＡ剤）を１重量％添加、１／３Ｍ−硫酸溶液によりｐＨを５．３に調整後、バイブロエクスプローラ混合機で４分間混合後、１０日後に酸化剤として３５％過酸化水素水を３重量％添加し、１／３Ｍ−硫酸溶液を添加によりｐＨを５．１に調整後、再びバイブロエクスプローラ混合機で４分間混合した。
【００６１】
実施例５は、汚染土壌に金属系処理剤（ＭＡ剤）（１重量％）、酸化剤として３５％過酸化水素水（３重量％）、及び１／３Ｍ−硫酸溶液を同時に添加し、ｐＨを５．２に調整後、バイブロエクスプローラ混合機で４分間混合した。
【００６２】
比較例８は汚染土壌に同和鉱業製Ｅ２００鉄粉（１重量％）、酸化剤として３５％過酸化水素水（３重量％）、及び１／３Ｍ−硫酸溶液を同時に添加し、ｐＨを５．３に調整後、バイブロエクスプローラ混合機で４分間混合した。
【００６３】
実施例６は、汚染土壌に金属系処理剤（ＭＡ剤）を１重量％添加、１Ｍ−硫酸溶液によりｐＨを１．２に調整後、バイブロエクスプローラ混合機で４分間混合後、１０日後に酸化剤として３５％過酸化水素水、３重量％添加、再びバイブロエクスプローラ混合機で４分間混合した。
【００６４】
実施例７は汚染土壌に金属系処理剤（ＭＡ剤）を１重量％添加、ｐＨ調整剤として１／３Ｍ−水酸化ナトリウム溶液によりｐＨを８．６に調整後、バイブロエクスプローラ混合機で４分間混合した。１０日後に酸化剤として３５％過酸化水素水、３重量％添加、再びバイブロエクスプローラ混合機で４分間混合した。
【００６５】
比較例９は、汚染土壌に１／３Ｍ−硫酸溶液を添加によりｐＨを５．２に調整後、酸化剤として３５％過酸化水素水を３重量％添加後、バイブロエクスプローラ混合機で４分間混合した。
【００６６】
実施例１〜７、比較例７〜９における混合状態は該汚染土壌が液状化し混合機の中で処理土壌自体が自転していることが確認できた。また、金属系処理剤の塊は認められなかった。
【００６７】
比較例１０
汚染土壌に１／３Ｍ−硫酸溶液を添加しｐＨを６．３に調整後、ニ軸ミキサーで４分間混合した。
【００６８】
比較例１１
汚染土壌に金属系処理剤としてＭＡ剤を１重量％添加、ｐＨ調整剤として１／３Ｍ−硫酸溶液によりｐＨを５．３に調整後、ニ軸ミキサーで４分間混合した。混合状態は４分後も金属系処理剤が一部土壌中で認められ均一に混合されておらず、液状化混合されていなかった。
【００６９】
比較例１２
汚染土壌に金属系処理剤（ＭＡ剤）を１重量％添加、ｐＨ調整剤として１／３Ｍ−硫酸溶液によりｐＨを５．３に調整後、ニ軸ミキサーで４分間混合した。１０日後に酸化剤として３５％過酸化水素水を３重量％添加、再びニ軸ミキサーで４分間混合した。混合状態は比較例１１と同様、金属系処理剤が一部土壌中で認められ均一に混合されておらず、液状化混合されていなかった。
【００７０】
各ＶＯＣ濃度の分析方法としては、比較例１〜３及び比較例４〜６と同様である。また、実施例１〜７、比較例７〜１２のＶＯＣ濃度の経時変化および各ＶＯＣ濃度が環境基準値未満になった分解日数を求め、これらの結果を表２および表３に示し、汚染土壌中の各ＶＯＣ濃度の経時変化を図４（実施例１、３）および図５（比較例１１、１２）に示した。
【００７１】
【表２】

【表３】

表２及び図４から明らかな様に、実施例１〜６では、バイブロエクスプローラ混合処理後、３９日以内にＰＣＥ、ＴＣＥ、Ｃｉｓ−ＤＣＥ共、各ＶＯＣの環境基準（０．０１、０．０３、０．０４ｐｐｍ）をクリアできた。尚、表２には示していないが、分解生成物としてエチレンおよびエタンは認められたが、環境基準項目の揮発性有機塩素化合物は副生していないことを確認した。
【００７２】
一方、表３及び図５から明らかな様に、比較例１０〜１２は被処理物をニ軸ミキサ混合処理のため、９０日経過後も環境基準をクリアできず、更に１，１−ＤＣＥ、ＤＣＭが副生していた。
【００７３】
従って、実施例１〜６では、被処理物をバイブロエクスプローラ混合する際、金属系処理剤（ＭＡ剤）または金属系処理剤（ＭＡ剤）および酸化剤を添加し、混合物のｐＨ調整をする本発明処理方法により、ＶＯＣ汚染土壌においても難分解性といわれているＣｉｓ−ＤＣＥ等を分解する能力は顕著であり、短期間に、かつ分解副生物として環境基準対象物を生成せずに法的規制値をクリアできることが分った。
【００７４】
実施例８
ＶＯＣとして５．８ｐｐｍ−ＰＣＥ、６．１ｐｐｍ−ＴＣＥ及び４．８ｐｐｍ−Ｃｉｓ−ＤＣＥを含有する粘土質汚染土壌の無害化処理を行なった。
【００７５】
原位置型処理方法として、図６に本発明の無害化装置を示す。該汚染土壌１にφ５０ｃｍのアースオーガ（アースドリル）２により地下方向に３ｍまで掘削する。その際、アースオーガ内、中空部３よりｐＨ調整剤４（１／３Ｍ−硫酸）及びＭＡ剤５（対土壌３重量％添加）を同時に空気圧縮機７により注入する。１時間後、該アースオーガの地上部に振動発生装置（２００Ｗ出力）８を取り付け３０分間土壌を振動させる。地表から混合状態を観察すると振動しているアースオーガ付近を含め液状化混合が確認できた。その後、該アースオーガを抜き出し、深度３ｍ地点の処理土壌をサンプリングし、そのうち３０ｇ処理土壌を１５０ｍｌバイアルビンに挿入、密閉した。比較例１〜３と同様の測定法によりＶＯＣ濃度の経時変化を５日間隔で測定した。
【００７６】
実施例９
該中空部３より該ｐＨ調整剤４及び該ＭＡ剤５の他に酸化剤として３５％過酸化水素水６（対土壌３重量％添加）を同時に空気圧縮機７により注入する以外は、実施例８と同様の操作で無害化処理を実施し、ＶＯＣ濃度の経時変化を測定した。
【００７７】
比較例１３〜１4
振動発生装置を取り付けていない一般的な一軸ドリルで混合した以外は、実施例８〜９と同様の方法で実施した。
【００７８】
実施例１０
実施例８〜９で用いた汚染土壌を用いて、連続式液状化混合処理を行なった。図７に連続式無害化装置を示す。該掘削汚染土壌９、５０トンを掘削し、２５トン／時間の送り速度で日立建機製振動機能付き土質改良機１０にｐＨ調整剤４（１／３Ｍ−硫酸）及びＭＡ剤５（対土壌３重量％添加）を同時に投入した。２時間後処理土壌をサンプリングし、そのうち３０ｇ処理土壌を１５０ｍｌバイアルビンに挿入、密閉した。比較例１〜３と同様の測定法によりＶＯＣ濃度変化を５日間隔で測定した。
【００７９】
実施例１１
２５トン／時間の送り速度で振動機能付き土質改良機１０にｐＨ調整剤４及びＭＡ剤５、他に酸化剤として過酸化水素水６（対土壌３重量％添加）を同時に投入する以外は実施例１０と同様の操作で無害化処理を実施し、ＶＯＣ濃度の経時変化を測定した。
【００８０】
比較例１５〜１６は混合機に日立建機製土壌改良機（１軸スクリュー付き、送り速度５０トン／時間）を用い、その他、処理剤および処理条件は実施例１０〜１１と同様である。
【００８１】
表４に原位置処理法（実施例８〜９、比較例１３〜１４）および連続式処理法（実施例１０〜１１、比較例１５〜１６）によるＶＯＣ濃度変化を示す。
【００８２】
【表４】

実施例８〜９は振動機能付きアースオーガにより原位置処理したものであり、両者とも４０日後には環境基準をクリアし、エタンおよびエチレンを主成分とした副生物のみが認められた。
【００８３】
比較例１３〜１４は一般的なアースオーガ（振動機能無し）により原位置処理したものであるが、両者とも４０日後も環境基準をクリアできなかった。分解副生物としてエタンおよびエチレンの他に１，１−ＤＣＥが認められた。
【００８４】
実施例１０〜１１は振動機能付き土壌改良機に掘削した汚染土壌を振動混合処理したものであり、両者とも４０日後には環境基準をクリアしていた。エタンおよびエチレンを主成分とした分解副生物以外は認められなかった。
【００８５】
比較例１５〜１６は土壌改良機（１軸スクリュー付き、送り速度５０トン／時間）に掘削土壌を混合処理したものであるが、主成分としてエタンおよびエチレンの他、塩ビ、１，１−ＤＣＥの分解副生物が認められた。
【００８６】
【発明の効果】
以上の説明から明らかなように、有機ハロゲン化合物で汚染された被処理物を無害化処理する方法において、被処理物をＦｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末と液状化混合することにより短期間に、かつ分解副生物として環境基準対象物を生成せずに法的規制値をクリアできることが分った。また、本発明処理は連続処理、掘削工程無しに地下深部まで無害化する原位置処理が可能である。混合の際、液状化混合物のｐＨが７未満であること、または被処理物にＦｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末、又はＦｅ粉末内および表面にＮｉ成分が偏析した部分合金粉末および酸化剤を添加し、被処理物を液状化混合することがさらに効果が顕著と成る。
【図面の簡単な説明】
【図１】バイブロエクスプローラ、ＶＭＹＣ−２５型を示した図。
【図２】ダブルミキサーＷＡ型を示した図。
【図３】ＶＯＣ汚染土壌をバイブロエクスプローラ混合機またはニ軸ミキサ混合機により混合処理した土壌中のＶＯＣ濃度の経時変化を示した図。
【図４】金属系処理剤、ｐＨ調整剤および酸化剤を添加し、ＶＯＣ汚染土壌をバイブロエクスプローラ混合機により液状化混合処理した土壌中のＶＯＣ濃度の経時変化を示した図。
【図５】金属系処理剤、ｐＨ調整剤および酸化剤を添加し、ＶＯＣ汚染土壌をニ軸ミキサ混合機により混合処理した土壌中のＶＯＣ濃度の経時変化を示した図。
【図６】振動機能付きアースオーガ（アースドリル）により地下汚染土壌を無害化処理する原位置処理図。
【図７】振動機能付き土壌改良機による掘削土壌の無害化処理図。
【符号の説明】
１汚染土壌
２アースオーガ（アースドリル）
３アースオーガ内，中空部
４ｐＨ調整剤および供給装置
５ＭＡ剤および供給装置
６酸化剤および供給装置
７空気圧縮機
８振動発生装置
９掘削汚染土壌
１０振動機能付き土質改良機[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a detoxification method for an object to be treated such as soil, industrial waste, sludge, sludge and the like contaminated with an organic halogen compound.
[0002]
[Prior art]
Environmental pollution problems due to organic halogen compounds such as TCE (trichloroethylene), PCE (tetrachloroethylene), DCM (dichloromethane), PCB (polychlorinated biphenyl) and dioxins are becoming apparent and becoming a major problem in various parts of the world.
[0003]
In response to these problems, treatment agents for detoxification of soil, wastewater, groundwater, etc. contaminated by volatile organic halogen compounds (VOC) and treatment methods thereof have been studied, and several technical reports and patent applications have been filed. Yes.
[0004]
The following treatment methods for contaminated soil, sludge, sludge, etc. are known.
[0005]
1) There is a VOC gas suction / activated carbon adsorption treatment method in the soil, but it can be treated only in the vicinity of the gas suction, so it takes a long time for treatment, and the treatment cost including activated carbon regeneration treatment that adsorbs VOC is high. It is a problem.
[0006]
2) The thermal desorption method and thermal decomposition method in which a heating electrode is inserted into the excavated soil or directly into the soil, and heat treatment requires a large heating device, and the vicinity of the electrode is thermally decomposed, but in other places It is not a fundamental treatment method because VOC is volatilized.
[0007]
3) The bioremediation method of detoxifying with a reducing substance via microorganisms requires a long time for detoxification, and is not compatible with all types of soils, and cannot be completely detoxified.
[0008]
Recently, as a chemical treatment,
4) As a reduction treatment method in which an iron-based treatment agent is added to contaminated soil, a method is disclosed in which excavated soil and an iron-based treatment agent are mixed and piled up on the ground in a pile shape (for example, a patented treatment). 1)) However, if the contact probability between the pollutant and the iron powder is low, a long time is required for purification.
[0009]
Although a method for injecting iron powder into contaminated soil by compressed air or water pressure is disclosed (for example, see Patent Documents 2 to 4), it is difficult to uniformly inject iron powder into the entire region of the contaminated soil. I think that the.
[0010]
Although the processing method which adds a water supply agent to a contaminated soil with iron powder is disclosed (for example, refer patent document 5), the soil strength countermeasure after the uniform mixing or detoxification process of a water supply agent and iron powder is a problem. Become.
[0011]
On the other hand, 5) a method of adding hydrogen peroxide or potassium permanganate as an oxidizing agent to iron powder as an oxidation treatment method is disclosed (for example, see Patent Documents 6 to 8). In order to uniformly mix the oxidizer, it is necessary to add a cement-based soil conditioner or sand using a special two- or more-shaft mixer, and to mix for a long time.
[0012]
[Patent Document 1]
JP 2001-000577 A
[Patent Document 2]
Japanese Patent Laid-Open No. 2002-200478
[Patent Document 3]
JP 2000-135483 A
[Patent Document 4]
JP 2001-038341 A
[Patent Document 5]
JP 2002-159960 A
[Patent Document 6]
JP 2001-276799 A
[Patent Document 7]
JP 2002-326080 A
[Patent Document 8]
JP 2003-80223 A
[0013]
[Problems to be solved by the invention]
As described above, conventional treatment methods for soil, industrial waste, sludge, sludge, etc. contaminated with organic halogen compounds have a long treatment period due to insufficient mixing of each treatment agent and material to be treated. There are problems such as being complicated, treatment method being complicated, and environmental standard value of the corresponding pollutant cannot be cleared. In particular, it is necessary to increase the mixing efficiency with low cost and low energy in a place where contamination is localized.
[0014]
The object of the present invention is to reduce the organic halogen compound in the object to be treated at a low cost and to make the target organic halogen compound below the environmental standard corresponding to the short term by the homogeneous mixing method, soil contaminated with the organic halogen compound, industrial waste It is intended to provide a detoxification method for an object to be treated such as sludge and sludge.
[0015]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present inventor has studied a method of detoxifying a workpiece contaminated with VOC in a short time by uniform mixing, particularly liquefaction mixing. In other words, the VOC in the object to be processed is reduced to the environmental standard or lower by the method of liquefying and mixing the object to be processed. furtherPartial alloy powder with Ni component segregated in and on Fe powderIn addition, it is possible to detoxify in a short time by a method of adding an oxidant and liquefying and mixing, and preferably a method of adjusting the pH range of the liquefied mixture when liquefied and mixed.
[0016]
The present invention is described in detail below.
[0017]
The present invention relates to a method for detoxifying an object to be treated contaminated with an organic halogen compound in a method for detoxifying the object to be treated contaminated with an organic halogen compound, wherein the object to be treated is liquefied and mixed. Method and workpiecePartial alloy powder with Ni component segregated in and on Fe powderOrPartial alloy powder with Ni component segregated in and on Fe powderFurther, the present invention relates to a treatment method for detoxifying an object to be treated contaminated with an organic halogen compound, wherein an oxidant is added and the object to be treated is liquefied and mixed.
[0018]
In the detoxification method of the present invention, the object to be detoxified is contaminated with an organic halogen compound. Examples of the organic halogen compound include DCM, carbon tetrachloride, chloroform, 1,2-dichloroethane. 1,1-DCE (1,1-dichloroethylene), Cis-DCE (Cis-dichloroethylene), Trans-DCE (trans-1,2-dichloroethylene), MC (1,1,1-trichloroethane), 1,1 , 2-trichloroethane, TCE, PCE, organochlorine compounds such as 1,3-dichloropropene, or these organic bromine compounds, etc., and the treated materials include soil, industrial waste, sludge, sludge, etc. Is mentioned.
[0019]
The liquefaction of the present invention is a state in which the particles of the water-containing processed material are separated from each other and floated on water, and finally each particle sinks and water comes out on the surface of the processed material. Say. In appearance, the workpiece itself rotates in the mixer during mixing.
[0020]
As the liquefaction mixing method of the present invention, 1) a method using a kneader, mixer or granulator having a vibration function, and 2) particularly a kneader having a vibration function includes, for example, a vibration mixer and a vibro mixer. There is a Vibro Explorer or a rod built-in type external circular vibration type kneader. In addition, on the workpiecePartial alloy powder with Ni component segregated in and on Fe powderOrPartial alloy powder with Ni component segregated in and on Fe powderAnd 3), for example, a soil conditioner having a vibration function is used as a continuous type, and in a container having a vibration function, an object to be treated andPartial alloy powder with Ni component segregated in and on Fe powderOr to-be-processed object,Partial alloy powder with Ni component segregated in and on Fe powder4) In the in-situ treatment method in which the contaminated soil is directly detoxified, the surface of the object to be treated contaminated with an organic halogen compound. Drilling a hole in the hole, and a steel rod, rod, drill or screw having a vibration function in the hole, andPartial alloy powder with Ni component segregated in and on Fe powderOrPartial alloy powder with Ni component segregated in and on Fe powderAnd an oxidant can be inserted and liquefied and mixed.
[0021]
In addition, the liquefaction mixing time can be defined from the mixing time in a small-scale mixer, and more efficient mixing can be achieved by estimating the vibration mixing conditions (vibration output, etc.) from the physical properties such as soil permeability and water content. .
[0022]
Next to the workpiecePartial alloy powder with Ni component segregated in and on Fe powderAs a method of adding and liquefying and mixing the oxidizer, a treatment object contaminated with an organic halogen compound is used.Partial alloy powder with Ni component segregated in and on Fe powderA method of adding and mixing only,Partial alloy powder with Ni component segregated in and on Fe powderAnd a method of simultaneously adding and mixing the oxidizing agent, orPartial alloy powder with Ni component segregated in and on Fe powderAfter adding and mixing, a method of adding and mixing the oxidizing agent can be employed.
[0023]
  What is important in these addition / mixing methods is to adjust the pH of the liquefied mixture at the time of mixing, so that it can be made harmless in a short period of time. The pH range is preferably less than 7, and more preferably 1 or more. When the pH of the mixture is 7 or more, the resolution is significantly lowered. On the other hand, if the pH of the mixture is less than 1, hydrogen is generated and the decomposition efficiency by the metal-based treatment agent is lowered. The pH adjustment time isPartial alloy powder with Ni component segregated in and on Fe powderIt can be performed before and after the addition and before and after the addition of the oxidizing agent.
[0024]
The pH is adjusted using a pH adjusting agent. Examples of the pH adjuster include inorganic acids such as sulfuric acid, phosphoric acid, hydrochloric acid, nitric acid, succinic acid, and phthalate. Among them, at least one selected from sulfuric acid, phosphoric acid, and hydrochloric acid is used to adjust the pH. Is preferably adjusted.
[0025]
  Partial alloy powder with Ni component segregated in and on Fe powderThe amount of the oxidizing agent added varies depending on the liquefaction mixing time, the amplitude of the mixer, the contamination concentration of the object to be treated, etc., but since the liquefaction mixing of the present invention is very excellent homogeneous mixing, Compared with the agent, purification to less than the environmental standard value can be achieved with a small addition amount. Of the present inventionPartial alloy powder with Ni component segregated in and on Fe powderIn consideration of its decomposition activity and economic efficiency, the amount of is preferably 0.1 to 10% by weight, particularly 1 to 5% by weight, based on the material to be treated such as wet soil. The amount of oxidant added isPartial alloy powder with Ni component segregated in and on Fe powderHowever, it is preferably 0.1 to 20% by weight, particularly preferably 0.5 to 10% by weight based on the object to be treated.
[0026]
  As a metal processing agent used in the present invention,Partial alloy powder with Ni component segregated in and on Fe powderIs used. More preferably, an alloy powder or a partial alloy powder obtained by a mechanical alloying (MA) method, which is also called a mechanical alloying method, can be used for the mixture of the Fe powder and Ni powder. In particular, it is necessary to set the mixing amount and mixing state of the Ni component with respect to the Fe component, that is, the optimum alloying and partial alloying state. Specifically, 0.01 to 2 parts by weight, preferably 0.1 to 0.5 parts by weight, more preferably 0.1 to 0.3 parts by weight of Ni powder is mixed with 100 parts by weight of the Fe powder. . Surprisingly, the reduction resolution of the workpiece is remarkably improved in this range. When the Ni powder is less than 0.01 part by weight, the resolution of the organic halogen compound is lowered, and is comparable to the resolution of only the Fe powder not added with the Ni powder, and the resolution is insufficient. Even if it exceeds 2 parts by weight of Ni powder, the resolution does not increase any more, and since Ni is more expensive than Fe, it is considerably disadvantageous in terms of cost.
[0027]
The Ni powder used in the MA method in the present invention includes pure Ni powder, industrial Ni powder, and ferronickel powder. Generally available industrial Ni powder has a particle size of 10 to 100 μm, and fine Ni powder of about 1 to 10 μm can be suitably used.
[0028]
Below, the manufacturing method of the metal type processing agent by MA method of this invention is demonstrated.
[0029]
The Fe powder and Ni powder are adjusted to a predetermined composition and mixed and homogenized by a general ball mill, V mixer, or the like. In some cases, it is also possible to eliminate the mixing step by adopting a quantitative feeder or the like in the MA method apparatus. As an apparatus used in the MA method, for example, an attritor mill (also called a stirring ball mill or an attrition mill), a vibration mill, or a rotary mill (including mechanofussion) batch type or continuous type pulverizer is used. The processing conditions differ depending on the apparatus to be used and are not uniquely determined, but can usually be employed within the range of specification conditions of each apparatus. Among these apparatuses, an attritor mill capable of minimizing the processing time is particularly preferable. The processing conditions include 7 parts of a grinding medium such as a steel ball with respect to 1 part by weight of a mixture of Fe powder and Ni powder. Charge 15 times. When the raw material may be oxidized by air during processing, an inert gas such as nitrogen gas can be flowed. The mill rotational speed is preferably 200 to 800 rpm. The processing time is not particularly limited but is preferably 0.5 to 50 hours since high degradation activity can be expressed. When the processing time is 0.5 to 6 hours, it becomes a partial alloy in which the Ni component is segregated in the Fe powder and on the surface, and it is particularly preferable because high activity can be obtained.
[0030]
Partial alloy powder with Ni component segregated in and on Fe powderThe shape is not particularly limited, and includes spherical shape, dendritic shape, piece shape, needle shape, square shape, laminated shape, rod shape, plate shape, sponge shape and the like.
[0031]
Partial alloy powder with Ni component segregated in and on Fe powderSpecific surface area of 0.05m²/ G or more, especially 0.2 to 10 m²/ G is preferred.
[0032]
  The particle size of the partial alloy powder in which the Ni component is segregated in the Fe powder and on the surface thereof can improve the decomposition reaction rate by using a particle size that passes through a 200 μm sieve, preferably 30 to 100 μm. Especially the specific surface area is 0.2m²When using a metal-based treating agent having a particle size of not less than / g and a particle size of not more than 75 μm, it is desirable that Cis-DCE, MC and PCE, which are hardly decomposable, can be decomposed in a shorter time.
[0033]
Next, examples of the oxidizing agent used in the present invention include ozone, sodium hypochlorite, bleached powder, zinc oxide, titanium oxide, hydrogen peroxide, persulfate, permanganate, and hydroxyl radical. At least one selected from hydrogen peroxide, persulfate, permanganate, and hydroxyl radical is preferable, and it is preferable to add these in a solution. Among these, persulfate and hydrogen peroxide are particularly preferable because they can be easily handled with an aqueous solution.
[0034]
  Also,Partial alloy powder with Ni component segregated in and on Fe powderIn addition, surfactants such as sodium dodecyl sulfate and Triton-X, and foaming agents such as ammonium carbonate and sodium bicarbonate can be used in combination as agents that further promote uniform mixing without degrading the performance of the oxidizing agent. .
[0035]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited at all by these Examples.
[0036]
In the examples, as a liquefaction mixer, Abe Industries' Vibro Explorer, VMYC-25 type (730 rpm), and FIG. 1 were used. Further, as a comparative mixer, a double mixer WA type (16 rpm) manufactured by Kitagawa Iron Works, FIG. 2 was used.
[0037]
As Fe powder used for metal processing agents (product name E200 manufactured by Dowa Mining), reduced iron powder (product name KIP-100T manufactured by Kawasaki Steel Co., Ltd.) as raw material iron powder used for MA method, and as raw material Ni powder Ni powder (purity 99%, particle size 2 to 3 μm grade product) manufactured by Soegawa Rika Co., Ltd. was used.
[0038]
  Comparative Example 1
  Detoxification treatment was performed on clay-contaminated soil containing 0.25 ppm-PCE, 0.35 ppm-TCE and 0.35 ppm-Cis-DCE as VOC. As a treatment method, 150 kg of the contaminated soil (water content 30% by weight) was sieved with a 5 cm wire mesh, and the passing soil was mixed for 20 minutes with a Vibro Explorer mixer. The pH at the time of mixing was 6.4. 30 g of the treated soil thus obtained was inserted into a 125 ml vial and sealed.
[0039]
The mixing conditions of the Vibro Explorer mixer were set so that three steel rods of φ100 mm were built in the mixer and the vibration load was 730 rpm and both amplitudes were 10 mm.
[0040]
  Comparative Example 2
  Detoxification treatment was performed on clay-contaminated soil containing 0.23 ppm-PCE, 0.30 ppm-TCE and 0.30 ppm-Cis-DCE as VOC. The pH at the time of mixing was 7.5. Other processing conditions areComparative Example 1It is the same.
[0041]
Comparative Example 3
  Detoxification treatment was performed on clay-contaminated soil containing 0.20 ppm-PCE, 0.28 ppm-TCE and 0.20 ppm-Cis-DCE as VOC. The pH at the time of mixing was 8.2. Other processing conditions areComparative Example 1It is the same.
[0042]
  Comparative Example 4
  Comparative Example 1Except using a double mixer (biaxial mixer) WA type (16 rpm) as a kneading machineComparative Example 1Were operated under the same processing conditions. The pH at the time of mixing was 6.6.
[0043]
  Comparative Example 5
  Comparative Example 2Except using a double mixer (biaxial mixer) WA type (16 rpm) as a kneading machineComparative Example 2Were operated under the same processing conditions. The pH at the time of mixing was 7.6.
[0044]
  Comparative Example 6
  Comparative Example 3Except using a double mixer (biaxial mixer) WA type (16 rpm) as a kneading machineComparative Example 3Were operated under the same processing conditions. The pH at the time of mixing was 8.6.
[0045]
  As a method for analyzing each VOC concentration, the VOC concentration was quantitatively analyzed over time using a headspace method based on JIS K0125 (method for testing volatile organic compounds in water and wastewater) described in Ministry of the Environment Notification No. 18 . Also,Comparative Examples 1-3 and Comparative Examples 4-6The decomposition days when the VOC concentration was less than the environmental standard values (PCE: 0.01 ppm, TCE: 0.03 ppm, cis-DCE: 0.04 ppm) were obtained, and these results are shown in Table 1 and are shown in Table 1 The time course of each VOC concentration is shown in FIG.Comparative Examples 1-3, Comparative Examples 4-6)Pointing out toungue.
[0046]
[Table 1]

  Comparative Examples 1-3Confirms that when mixing is started, the contaminated soil liquefies and the soil itself rotates in the mixer. As can be seen from Table 1 and FIG.,After 90 days, it became below the environmental standard. Although not shown in Table 1, it is confirmed that environmental standard objects are not generated as decomposition by-products.
[0047]
  Comparative example4-6Was due to the mixing treatment by the biaxial mixer, but the liquefaction phenomenon of the object to be treated was not recognized and was mixed as a solid. After mixing for 20 minutes, each VOC concentration tended to decrease slightly, but even after 90 days, each VOC concentration could not pass the environmental standards.
[0049]
  Example1-7, Comparative Examples 7-9
  Detoxification treatment was performed on clay-contaminated soil (pH 6.8) containing 4.5 ppm-PCE, 3.0 ppm-TCE and 3.1 ppm-Cis-DCE as VOC. As a treatment method, 150 kg of the contaminated soil (water content 28% by weight) is sieved with a 5 cm wire mesh, and the passing soil is shown in Table 2.YouFe-0.3 wt% Ni (MA agent) processed with MA as a metal-based treatment agent, or iron powder with 1 wt% (1.5 kg) of contaminated soil added, and 35% hydrogen peroxide solution as an oxidizing agent against contamination 3% by weight of soil was added, 1 / 3M-sulfuric acid was added as a pH adjuster, and mixed for 4 minutes with a Vibro Explorer mixer.
[0050]
30 g of the treated soil thus obtained was inserted into a 125 ml vial and sealed.
[0051]
The mixing conditions of the Vibro Explorer mixer were set so that three steel rods of φ100 mm were built in the mixer and the vibration load was 730 rpm and both amplitudes were 10 mm.
[0052]
  Example1-5,6-7The production conditions for the metal-based treatment agent (MA agent) used in the above are shown below.
[0053]
After mixing 1 kg of raw material consisting of reduced iron powder (KIP-100T made by Kawasaki Steel Co., Ltd.) and 0.3 parts by weight (100 parts by weight of iron powder) Ni powder (manufactured by Soekawa Rika) for 10 minutes with a ball mill, it has a 5 L pot. The steel ball (SUJ2) was charged together with 7.5 kg in an attritor mill (trade name DYNAMICCILL, MA1D type, manufactured by Mitsui Mining Co., Ltd.) and MA processed. The nitrogen gas flow rate at this time was 40 ml / min. As MA processing conditions, the processing was performed for 1 hour and the rotational speed was 400 rpm.
[0054]
  Comparative Example 8The iron powder used in is Dowa Mining E200.
[0055]
In addition, the specific surface area of the metal processing agent used this time is 0.25 m.²/ G, powder that passed through a 75 μm sieve was used.
[0056]
  Comparative Example 7Adjusted the pH to 6.3 with 1/3 M-sulfuric acid solution in the contaminated soil and then mixed with Vibro Explorer mixer for 4 minutes.
[0057]
  Example1Added 1% by weight of a metal treatment agent (MA agent) to the contaminated soil, adjusted the pH to 5.1 with a 1/3 M sulfuric acid solution, and then mixed for 4 minutes with a Vibro Explorer mixer.
[0058]
  Example2Added 1% by weight of metal-based treatment agent (MA agent) to contaminated soil, mixed for 4 minutes with Vibro Explorer mixer, added 3% by weight of 35% hydrogen peroxide as an oxidant 10 days later, mixed again with Vibro Explorer Mix for 4 minutes on the machine. The pH at the time of mixing was 6.3.
[0059]
  Example3Added 1% by weight of metal-based treatment agent (MA agent) to contaminated soil, adjusted pH to 5.5 with 1 / 3M sulfuric acid solution, mixed for 4 minutes with Vibro Explorer mixer, and oxidant after 10 days As a result, 3% by weight of 35% hydrogen peroxide solution was added and again mixed for 4 minutes with a Vibro Explorer mixer. The pH at the time of mixing was 5.5.
[0060]
  Example4Added 1% by weight of metal-based treatment agent (MA agent) to contaminated soil, adjusted pH to 5.3 with 1 / 3M sulfuric acid solution, mixed for 4 minutes with Vibro Explorer mixer, and oxidant after 10 days 3% by weight of 35% hydrogen peroxide solution was added, and the pH was adjusted to 5.1 by adding 1 / 3M sulfuric acid solution, and then mixed again with a Vibro Explorer mixer for 4 minutes.
[0061]
  Example5Add a metal-based treatment agent (MA agent) (1% by weight) to the contaminated soil, 35% hydrogen peroxide (3% by weight) as an oxidizing agent, and 1 / 3M sulfuric acid solution at the same time, and adjust the pH to 5. After adjusting to 2, it was mixed for 4 minutes with a Vibro Explorer mixer.
[0062]
  Comparative Example 8Added to the contaminated soil E200 iron powder (1% by weight) made by Dowa Mining Co., Ltd., 35% hydrogen peroxide (3% by weight) and 1 / 3M-sulfuric acid solution as oxidants at the same time to adjust the pH to 5.3. Then, it mixed for 4 minutes with a Vibro Explorer mixer.
[0063]
  Example6Added 1% by weight of metal-based treatment agent (MA agent) to contaminated soil, adjusted pH to 1.2 with 1M-sulfuric acid solution, mixed for 4 minutes with Vibro Explorer mixer, and 35 days later as oxidant after 10 days. % Hydrogen peroxide solution, 3% by weight added, and again mixed for 4 minutes with a Vibro Explorer mixer.
[0064]
  Example7Added 1% by weight of a metal treatment agent (MA agent) to the contaminated soil, adjusted the pH to 8.6 with 1 / 3M sodium hydroxide solution as a pH adjuster, and then mixed for 4 minutes with a Vibro Explorer mixer. Ten days later, 3% by weight of 35% hydrogen peroxide solution was added as an oxidizing agent, and the mixture was again mixed for 4 minutes with a Vibro Explorer mixer.
[0065]
  Comparative Example 9Adjusted the pH to 5.2 by adding 1/3 M sulfuric acid solution to the contaminated soil, added 3% by weight of 35% hydrogen peroxide as an oxidizing agent, and then mixed for 4 minutes with a Vibro Explorer mixer.
[0066]
  Example1-7, Comparative Examples 7-9It was confirmed that the contaminated soil was liquefied and the treated soil itself was rotating in the mixer. Moreover, the lump of the metal type processing agent was not recognized.
[0067]
  Comparative example10
  A 1/3 M sulfuric acid solution was added to the contaminated soil to adjust the pH to 6.3, and then mixed for 4 minutes with a biaxial mixer.
[0068]
  Comparative example11
  1 weight% of MA agent was added to the contaminated soil as a metal-based treatment agent, and the pH was adjusted to 5.3 with a 1/3 M sulfuric acid solution as a pH adjuster, and then mixed for 4 minutes with a biaxial mixer. In the mixed state, even after 4 minutes, a part of the metal-based treatment agent was found in the soil and was not uniformly mixed, and was not liquefied and mixed.
[0069]
  Comparative example12
  1% by weight of a metal-based treatment agent (MA agent) was added to the contaminated soil, the pH was adjusted to 5.3 with a 1/3 M sulfuric acid solution as a pH adjuster, and then mixed with a biaxial mixer for 4 minutes. Ten days later, 3% by weight of 35% aqueous hydrogen peroxide was added as an oxidizing agent, and mixed again for 4 minutes with a biaxial mixer. The mixed state isComparative Example 11In the same manner as above, a part of the metal-based treatment agent was found in the soil and was not uniformly mixed, and was not liquefied and mixed.
[0070]
  As an analysis method of each VOC concentration,ComparisonExamples 1-3 and comparative examples4-6It is the same. Examples1-7, Comparative Examples 7-12The time-dependent changes in the VOC concentration and the number of days of degradation when each VOC concentration was less than the environmental standard value were obtained. Example1, 3) And FIG. 5 (comparative example)11, 12)Pointing out toungue.
[0071]
[Table 2]

[Table 3]

  As is clear from Table 2 and FIG.1-6Then, after the Vibro Explorer mixing process,39Within VEC, environmental standards (0.01, 0.03, 0.04 ppm) of each VOC could be cleared for both PCE, TCE, and Cis-DCE. Although not shown in Table 2, although ethylene and ethane were recognized as decomposition products, it was confirmed that volatile organochlorine compounds as environmental standard items were not by-produced.
[0072]
  On the other hand, as is apparent from Table 3 and FIG.10-12For mixing the workpieces with a twin-screw mixer,90Environmental standards could not be cleared even after the passage of days, and 1,1-DCE and DCM were further by-produced.
[0073]
  Therefore, the example1-6Then, when mixing an object to be treated with Vibro Explorer, a metal processing agent (MA agent) or a metal processing agent (MA agent) and an oxidizing agent are added to adjust the pH of the mixture. The ability to decompose Cis-DCE, which is said to be hardly degradable even in soil, is remarkable, and it is clear that legally regulated values can be cleared in a short period of time without generating environmental standard objects as decomposition byproducts. It was.
[0074]
  Example8
  Detoxification treatment was performed on clay-contaminated soil containing 5.8 ppm-PCE, 6.1 ppm-TCE and 4.8 ppm-Cis-DCE as VOCs.
[0075]
As an in-situ processing method, FIG. 6 shows a detoxifying apparatus of the present invention. The contaminated soil 1 is excavated to 3 m in the underground direction by an earth auger (earth drill) 2 having a diameter of 50 cm. At that time, the pH adjuster 4 (1/3 M-sulfuric acid) and the MA agent 5 (added 3% by weight of soil) are simultaneously injected by the air compressor 7 from the hollow portion 3 in the earth auger. After 1 hour, a vibration generator (200 W output) 8 is attached to the ground part of the earth auger and the soil is vibrated for 30 minutes. When the mixing state was observed from the ground surface, liquefaction mixing including the vicinity of the vibrating earth auger was confirmed. Thereafter, the earth auger was extracted, and the treated soil at a depth of 3 m was sampled, 30 g of which was inserted into a 150 ml vial and sealed.ComparisonThe change over time in the VOC concentration was measured at 5-day intervals by the same measurement method as in Examples 1-3.
[0076]
  Example9
  Example except that 35% hydrogen peroxide solution 6 (added 3% by weight of soil) as an oxidizing agent in addition to the pH adjusting agent 4 and the MA agent 5 is simultaneously injected from the hollow portion 3 by the air compressor 7.8The detoxification treatment was carried out in the same manner as in Example 1, and the change over time in the VOC concentration was measured.
[0077]
  Comparative example13-14
  Except for mixing with a general uniaxial drill without a vibration generator installed8-9It implemented by the same method.
[0078]
  Example10
  Example8-9Using the contaminated soil used in the above, continuous liquefaction mixing treatment was performed. FIG. 7 shows a continuous detoxification device. The excavated contaminated soil 9, 50 tons was excavated, and the pH adjuster 4 (1/3 M-sulfuric acid) and MA agent 5 (to soil 3) were added to the soil improvement machine 10 with vibration function manufactured by Hitachi Construction Machinery at a feed rate of 25 tons / hour. At the same time). After 2 hours, the treated soil was sampled, 30 g of which was inserted into a 150 ml vial and sealed.ComparisonThe change in VOC concentration was measured at 5-day intervals by the same measurement method as in Examples 1-3.
[0079]
  Example11
  Implemented except that pH adjuster 4 and MA agent 5 were added to soil conditioner 10 with vibration function at a feed rate of 25 tons / hour, and hydrogen peroxide solution 6 (addition of 3% by weight of soil) as an oxidizing agent was added simultaneously. Example10The detoxification treatment was carried out in the same manner as in Example 1, and the change over time in the VOC concentration was measured.
[0080]
  Comparative example15-16Uses a Hitachi Construction Machinery soil improver (with single screw, feed rate 50 tons / hour) as the mixer.10-11It is the same.
[0081]
  Table 4 shows in-situ processing methods (Examples).8-9Comparative example13-14) And continuous processing methods (Examples)10-11Comparative example15-16) Shows the change in VOC concentration.
[0082]
[Table 4]

  Example8-9Were in-situ treated with an earth auger with vibration function, both cleared the environmental standards after 40 days, and only by-products mainly composed of ethane and ethylene were observed.
[0083]
  Comparative example13-14Were processed in-situ with a general earth auger (no vibration function), but both failed to meet the environmental standards after 40 days. In addition to ethane and ethylene, 1,1-DCE was observed as a decomposition byproduct.
[0084]
  Example10-11Was a mixture of contaminated soil excavated in a soil conditioner with vibration function, both of which cleared environmental standards after 40 days. No decomposition byproducts other than ethane and ethylene were found.
[0085]
  Comparative example15-16Is a mixture of excavated soil in a soil conditioner (with a single screw, feed rate of 50 tons / hour). In addition to ethane and ethylene as main components, decomposition byproducts of PVC and 1,1-DCE are included. Admitted.
[0086]
【The invention's effect】
  As is clear from the above description, in the method of detoxifying a workpiece contaminated with an organic halogen compound, the workpiece isA partial alloy powder in which Ni component segregates in and on the Fe powder;It was found that the legal regulation value can be cleared by liquefaction mixing in a short period of time and without generating environmental standard objects as decomposition by-products. In addition, the processing according to the present invention enables continuous processing and in-situ processing for detoxifying the deep underground without any excavation process. When mixing, the pH of the liquefied mixture is less than 7, orPartial alloy powder with Ni component segregated in and on Fe powderOrPartial alloy powder with Ni component segregated in and on Fe powderFurther, the effect becomes more remarkable by adding an oxidizing agent and liquefying and mixing the object to be processed.
[Brief description of the drawings]
FIG. 1 is a diagram showing a Vibro Explorer, VMYC-25 type.
FIG. 2 shows a double mixer WA type.
FIG. 3 is a graph showing a change in VOC concentration over time in soil obtained by mixing VOC-contaminated soil with a Vibro Explorer mixer or a biaxial mixer mixer.
FIG. 4 is a graph showing the change over time in the concentration of VOC in soil in which a metal-based treating agent, a pH adjusting agent and an oxidizing agent are added and VOC-contaminated soil is liquefied and mixed with a Vibro Explorer mixer.
FIG. 5 is a graph showing the change over time in the VOC concentration in soil in which a metal-based treating agent, a pH adjusting agent and an oxidizing agent are added and VOC-contaminated soil is mixed by a biaxial mixer mixer.
FIG. 6 is an in-situ processing diagram for detoxifying underground contaminated soil with an earth auger (earth drill) with a vibration function.
FIG. 7 is a diagram of detoxification processing of excavated soil by a soil conditioner with a vibration function.
[Explanation of symbols]
1 Contaminated soil
2 Earth auger (earth drill)
3 Earth auger, hollow part
4 pH adjuster and supply device
5 MA agent and supply equipment
6 Oxidizing agent and supply device
7 Air compressor
8 Vibration generator
9 Excavated contaminated soil
10 Soil improvement machine with vibration function

Claims

In a method for detoxifying an object to be treated contaminated with an organic halogen compound, Ni is formed on the surface of the object to be treated and Ni powder 0.1 to 0.5 parts by weight with respect to 100 parts by weight of Fe powder and Ni on the surface. A treatment method for detoxifying an object to be treated contaminated with an organic halogen compound, comprising liquefying and mixing a partial alloy powder having segregated components.

In a method for detoxifying an object to be treated contaminated with an organic halogen compound, the object to be treated has Ni in the Fe powder and 0.1 to 0.5 parts by weight of Ni powder with respect to 100 parts by weight of Fe powder. The processing method according to claim 1, wherein the component contaminated with an organic halogen compound is detoxified, comprising adding a partial alloy powder having segregated components and an oxidizing agent, and liquefying and mixing the component to be processed.

The partial alloy powder in which the Ni component segregated in and on the surface of the Fe powder consisting of 0.1 to 0.5 parts by weight of Ni powder with respect to 100 parts by weight of Fe powder was 0.1 to 0% of Ni powder with respect to 100 parts by weight of Fe powder. A processing method for detoxifying an object contaminated with an organic halogen compound according to any one of claims 1 to 2, which is an alloy powder obtained by mechanically alloying a mixture of 5 parts by weight.

The amount of addition of the partial alloy powder in which the Ni component is segregated in and on the surface of the Fe powder consisting of 0.1 to 0.5 parts by weight of the Ni powder with respect to 100 parts by weight of the Fe powder is 0.1 to 10% by weight based on the workpiece. A processing method for detoxifying a workpiece contaminated with the organic halogen compound according to any one of claims 1 to 3 .

An object to be treated contaminated with an organic halogen compound according to any one of claims 2 to 4 , wherein the oxidizing agent is at least one selected from hydrogen peroxide, persulfate, hydroxyl radical, or permanganate. A detoxifying treatment method.

The treatment method for detoxifying a treatment object contaminated with an organic halogen compound according to any one of claims 2 to 5 , wherein an addition amount of the oxidizing agent is 0.1 to 20% by weight with respect to the treatment object.

The processing method which detoxifies the to-be-processed object contaminated with the organic halogen compound of any one of Claims 1 thru | or 6 which performs liquefaction mixing with the vibro mixer or vibro explorer provided with the vibration function.

A hole is drilled in the surface of the object to be treated contaminated with an organic halogen compound, and a steel rod, a rod, a drill or a screw having a vibration function in the hole, and Ni powder 0.1 to 100 parts by weight of Fe powder. Partial alloy powder in which Ni component is segregated on the surface and 0.5 parts by weight of Fe powder, or Ni powder in and on the surface of 0.1 to 0.5 parts by weight of Ni powder with respect to 100 parts by weight of Fe powder processing method component to detoxify the workpiece which has been contaminated with organohalogen compound as claimed in any of claims 2 to 7 is mixed liquefied insert portions alloy powder and oxidant segregated.

The processing method of detoxifying the to-be-processed object contaminated with the organic halogen compound according to any one of claims 1 to 8 , wherein the pH of the liquefied mixture is adjusted to less than 7 when the to-be-processed object is liquefied and mixed.

The processing method of detoxifying an object contaminated with an organic halogen compound according to claim 9 , wherein an inorganic acid is added when adjusting the pH of the liquefied mixture to less than 7.

The processing method for detoxifying an object contaminated with an organic halogen compound according to claim 10 , wherein the inorganic acid is at least one selected from sulfuric acid, phosphoric acid, and hydrochloric acid.