JP6341673B2 - Method for reducing leaching of pollutants from contaminated soil - Google Patents
Method for reducing leaching of pollutants from contaminated soil Download PDFInfo
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- JP6341673B2 JP6341673B2 JP2014013320A JP2014013320A JP6341673B2 JP 6341673 B2 JP6341673 B2 JP 6341673B2 JP 2014013320 A JP2014013320 A JP 2014013320A JP 2014013320 A JP2014013320 A JP 2014013320A JP 6341673 B2 JP6341673 B2 JP 6341673B2
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Description
本発明は汚染土壌から汚染物質が溶出する量を低減する方法に関するものである。 The present invention relates to a method for reducing the amount of contaminants eluted from contaminated soil.
揮発性有機化合物などの地下水汚染の問題を、大規模な土壌掘削をせずに改善する原位置対策が開発されている。
しかしその方法では、帯水層の下部の粘土層などの難透水層にまで浸みこんだ汚染物質への対策が容易ではなく、地下水対策が長期化するという問題があった。
その対策として、粘土層に不溶化剤を注入する方法も考えられるが、その場合には地下深くまでの大規模な工事が必要となる。
さらに関連する方法として下記の特許文献記載の方法が知られている。
In-situ measures have been developed to ameliorate groundwater contamination problems such as volatile organic compounds without extensive soil excavation.
However, this method has a problem in that it is not easy to take measures against pollutants that have soaked into a poorly permeable layer such as a clay layer under the aquifer, and the countermeasures for groundwater are prolonged.
As a countermeasure, a method of insolubilizing the clay layer may be considered, but in such a case, a large-scale construction deep into the underground is required.
Further, as a related method, a method described in the following patent document is known.
前記した従来の汚染土壌からの汚染物質の溶出低減方法にあっては、次のような問題点がある。
＜１＞ 特許文献１記載の発明の名称は「重金属で汚染された物質の処理方法」であり、具体的にはリン酸カルシウムゲルを生成し、これを汚染された物質と接触させて処理する方法である。この方法は不溶化剤の混合による不溶化を目的としており、汚染土壌を被覆することによる溶出の制御を目的としたものではない。そのためにゲルをあらかじめ作成して汚染土壌に混合または注入する方法であり、現地で実施する場合に土壌に掘削が必要であること、原位置で粘性土には注入できないこと、撹拌工法など大規模な改良工事が不可欠である、といった問題がある。
＜２＞ 特許文献２記載の発明の名称は「フッ素汚染土壌の処理方法」であり、フッ素などの汚染土壌や廃棄物に不溶化剤を混合する方法であって、リン酸塩鉱物またはその一種であるアパタイトの高い吸着能力と安定性を利用した発明である。
＜３＞ 特許文献３記載の発明の名称は「グラウトおよび地盤を固結する方法」であり、具体的には地盤中の微生物によって代謝分解されてアンモニアを発生させるアミノ酸、カルシウム塩ならびにリン酸および／またはリン酸塩を含んでなるグラウトに関するものである。このように特許文献３記載の発明は、アミノ酸、カルシウム塩、リン酸塩を用いて地盤を固結して地盤の強度の増加を目的とするもので、本発明の目的とは異なるものである。
The above-described conventional method for reducing the elution of pollutants from contaminated soil has the following problems.
<1> The name of the invention described in Patent Document 1 is “a method of treating a substance contaminated with heavy metals”, specifically, a method of producing a calcium phosphate gel and treating it by bringing it into contact with the contaminated substance. is there. This method is intended to insolubilize by mixing insolubilizing agents, and is not intended to control elution by covering contaminated soil. For this purpose, gels are prepared in advance and mixed or injected into contaminated soil. When carried out locally, excavation is required in the soil, it cannot be injected into viscous soil in situ, and a large-scale method such as a stirring method There is a problem that such improvement work is indispensable.
<2> The name of the invention described in Patent Document 2 is “treatment method of fluorine-contaminated soil”, which is a method of mixing an insolubilizing agent in contaminated soil or waste such as fluorine, and is a phosphate mineral or a kind thereof. This invention uses the high adsorption ability and stability of apatite.
<3> The name of the invention described in Patent Document 3 is “Method of consolidating grout and ground”, specifically, an amino acid, a calcium salt, and phosphoric acid that are decomposed by microorganisms in the ground to generate ammonia. And / or a grout comprising phosphate. As described above, the invention described in Patent Document 3 aims to increase the strength of the ground by consolidating the ground using amino acids, calcium salts, and phosphates, and is different from the purpose of the present invention. .
上記のような課題を解決するために、本発明の汚染土壌からの汚染物質の溶出低減方法は、注入井戸を前記汚染土壌上部まで掘削した後、前記汚染土壌の上部の帯水層中に薬剤を注入し、注入された前記薬剤がゲル化して汚染土壌の上面を被覆する膜となることを特徴とすることを特徴としたものである。
また本発明の方法は、上記の方法において、リン酸塩鉱物の膜を形成するための薬剤は、カルシウム溶液とリン酸溶液であることを特徴としたものである。
また本発明の方法は、上記の方法において、カルシウム溶液とリン酸溶液を注入するために、注入井戸の下部にのみスクリーンを設けて行うことを特徴とするものである。
In order to solve the above-described problems, the method for reducing the elution of pollutants from the contaminated soil according to the present invention includes excavating an injection well to the upper part of the contaminated soil and then a chemical agent in the aquifer above the contaminated soil. , And the injected drug is gelled to form a film covering the upper surface of the contaminated soil .
The method of the present invention, in the above method, the agent for forming a film of phosphate minerals is obtained by being a solution of calcium solution and a phosphoric acid.
In addition, the method of the present invention is characterized in that in the above method, a screen is provided only under the injection well in order to inject the calcium solution and the phosphoric acid solution.
本発明の汚染土壌からの汚染物質の溶出低減方法は以上説明したようになるから次のような効果を得ることができる。
＜１＞ 帯水層と難透水層の境界にある汚染土壌を、ゲル状の物質で被覆するため帯水層の底部の汚染源からの汚染物質の溶出を抑制することができ、地下水中の汚染物質濃度を低下することができる。
＜２＞ 汚染土壌を被覆する膜の形成する工程を、薬液の注入のみによって行うことができるから、従来のように地盤を掘削したり撹拌するような地盤を大きく乱すことがない。
Since the elution reduction method of the pollutant from the contaminated soil of the present invention is as described above, the following effects can be obtained.
<1> Since the contaminated soil at the boundary between the aquifer and the hardly permeable layer is covered with a gel-like substance, the elution of the pollutant from the contamination source at the bottom of the aquifer can be suppressed, and contamination in the groundwater The substance concentration can be reduced.
<2> Since the process of forming the film covering the contaminated soil can be performed only by injecting the chemical solution, the ground that is excavated and stirred as in the conventional case is not greatly disturbed.
以下図面を参照にしながら本発明の汚染土壌からの汚染物質の溶出低減方法の好適な実施の形態を詳細に説明する。 Hereinafter, preferred embodiments of a method for reducing the elution of pollutants from contaminated soil according to the present invention will be described in detail with reference to the drawings.
＜１＞前提条件。
本発明の方法を採用する対象となる状態は、帯水層Ａがあり、その下に難透水層Ｂが位置し、両層の境界に残留した汚染物質からなる汚染土壌Ｃが存在する地盤である。
汚染土壌Ｃとしては特に揮発性有機化合物などを対象とする。
このような揮発性有機化合物は、対策を施さない限り長年にわたって帯水層Ａに溶出を続ける。
<1> Precondition.
The state to which the method of the present invention is applied is a ground where there is an aquifer A, a hardly water permeable layer B is located below, and there is contaminated soil C composed of contaminants remaining at the boundary between both layers. is there.
As the contaminated soil C, volatile organic compounds are particularly targeted.
Such volatile organic compounds continue to elute in the aquifer A for many years unless measures are taken.
＜２＞リン酸塩鉱物の膜の形成。
このように帯水層Ａとその下の難透水層Ｂの境界に残留した汚染物質からなる汚染土壌Ｃを覆う状態で、リン酸塩鉱物の膜３を形成することが本発明の特徴である。
その結果、リン酸塩鉱物の膜３によって、汚染土壌Ｃからの汚染物質の溶出を低減させることができる。
このように本発明の方法では地下水汚染の対策が長期化する原因となっている帯水層Ａと難透水層Ｂの境界に位置する汚染土壌Ｃからの汚染物質の溶出付加を低下させるものである。
前記したように、従来は汚染土壌Ｃを取り除く方法や不溶化剤を混合する方法など、大掛かりな工事を必要とする対策しか存在しなかった。
それに対して本発明では、地盤の中でゲル化する薬剤を対象地域に注入して膜３によって被覆する方法を提案するものである。
<2> Formation of a phosphate mineral film.
Thus, it is a feature of the present invention that the phosphate mineral film 3 is formed so as to cover the contaminated soil C composed of the contaminants remaining at the boundary between the aquifer A and the hardly permeable layer B below. .
As a result, the elution of the pollutant from the contaminated soil C can be reduced by the phosphate mineral film 3.
As described above, the method of the present invention reduces the elution and addition of contaminants from the contaminated soil C located at the boundary between the aquifer A and the hardly permeable layer B, which is a cause of prolonged countermeasures against groundwater contamination. is there.
As described above, conventionally, there has been only a countermeasure requiring a large-scale construction such as a method of removing the contaminated soil C and a method of mixing an insolubilizing agent.
On the other hand, the present invention proposes a method in which a drug that gels in the ground is injected into the target area and covered with the film 3.
＜３＞ 使用する薬剤。
リン酸カルシウムゲルの膜３を生成させるための薬剤は２種類である。
すなわちカルシウム溶液１とリン酸溶液２である。
カルシウム溶液１としては、例えば塩化カルシウムやクエン酸などを採用することができる。
リン酸溶液２としては、例えばリン酸水素二ナトリウムやリン酸トリナトリウムなどを採用することができる。
これらの溶液は地盤内に注入したあとゆっくりとリン酸カルシウムゲルを形成する。
<3> Drug to be used.
There are two types of agents for producing the calcium phosphate gel film 3.
That is, the calcium solution 1 and the phosphoric acid solution 2.
As the calcium solution 1, for example, calcium chloride or citric acid can be employed.
As the phosphoric acid solution 2, for example, disodium hydrogen phosphate or trisodium phosphate can be employed.
These solutions slowly form calcium phosphate gels after being injected into the ground.
＜４＞注入方法。
上記の薬剤、すなわちカルシウム溶液１とリン酸溶液２を注入するために、注入井戸４を帯水層Ａと難透水層Ｂとの境界付近まで掘削する。
そして井戸４の最深部にのみスクリーンを設け、帯水層Ａと難透水層Ｂの境界付近にのみ薬剤が注入できるように構成する。
あるいは薬液注入パイプの先端を帯水層Ａと難透水層Ｂとの境界付近まで挿入する。
そして注入井戸４の最深部、あるいは注入パイプの最深部からカルシウム溶液１とリン酸溶液２を注入する。
注入した薬液は帯水層Ａより下の粘土層などの難透水層Ｂには浸入しないから両層の間に広がるが、これが徐々にゲル化して汚染土壌Ｃの上面を被覆する膜３となる。
その場合にゲル化する速度は溶液の配合によって制御することは容易である。
<4> Injection method.
In order to inject the above-mentioned chemicals, that is, the calcium solution 1 and the phosphoric acid solution 2, the injection well 4 is excavated to the vicinity of the boundary between the aquifer A and the hardly permeable layer B.
A screen is provided only at the deepest part of the well 4 so that the drug can be injected only near the boundary between the aquifer A and the hardly permeable layer B.
Alternatively, the tip of the chemical solution injection pipe is inserted to the vicinity of the boundary between the aquifer A and the hardly permeable layer B.
Then, the calcium solution 1 and the phosphoric acid solution 2 are injected from the deepest part of the injection well 4 or the deepest part of the injection pipe.
Since the injected chemical solution does not enter the poorly permeable layer B such as a clay layer below the aquifer A, it spreads between the two layers, but this gradually gels to form a film 3 that covers the upper surface of the contaminated soil C. .
In this case, the gelation rate can be easily controlled by the formulation of the solution.
＜５＞平面的対策。
一か所の注入井戸４や注入パイプを中心に、平面的に半径数メートの範囲の被覆膜３を形成することができる。
したがって複数の注入井戸４や注入パイプからの影響範囲を平面的にラップさせて注入作業を行うことで、広い範囲にわたって被覆する膜３を形成して汚染土壌Ｃからの汚染物質の溶出の低減を行うことができる。
<5> Plane measures.
A coating film 3 having a radius of several meters in plan can be formed around a single injection well 4 or injection pipe.
Therefore, the influence range from the plurality of injection wells 4 and the injection pipes is planarly wrapped to perform the injection operation, thereby forming the film 3 covering a wide range and reducing the elution of the pollutants from the contaminated soil C. It can be carried out.
１：カルシウム溶液
２：リン酸溶液
３：汚染土壌を被覆する膜
４：井戸
Ａ：帯水層
Ｂ：難透水層
Ｃ：汚染土壌
1: Calcium solution 2: Phosphate solution 3: Membrane covering contaminated soil 4: Well A: Aquifer B: Hardly permeable layer C: Contaminated soil
Claims (3)
注入井戸を前記汚染土壌の上部まで掘削した後、
前記汚染土壌の上部の帯水層中に薬剤を注入し、
注入された前記薬剤がゲル化して汚染土壌の上面を被覆する膜となることを特徴とする汚染土壌からの汚染物質の溶出低減方法
A method for reducing the elution of pollutants from contaminated soil at the boundary between an aquifer and a hard-permeable layer below it,
After drilling the injection well to the top of the contaminated soil,
Injecting the drug into the upper aquifer of the contaminated soil,
A method for reducing the elution of pollutants from contaminated soil , wherein the injected drug is gelled to form a film covering the upper surface of the contaminated soil
請求項１記載の汚染土壌からの汚染物質の溶出低減方法。
Wherein the agent is characterized by a solution of calcium solution and a phosphoric acid,
The method for reducing elution of pollutants from the contaminated soil according to claim 1 .
請求項１記載の汚染土壌からの汚染物質の溶出低減方法。
And performing provided screen only at the bottom of the injection wells,
The method for reducing elution of pollutants from the contaminated soil according to claim 1 .
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| JP2014013320A JP6341673B2 (en) | 2014-01-28 | 2014-01-28 | Method for reducing leaching of pollutants from contaminated soil |
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| JP2014013320A JP6341673B2 (en) | 2014-01-28 | 2014-01-28 | Method for reducing leaching of pollutants from contaminated soil |
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| JP6341673B2 true JP6341673B2 (en) | 2018-06-13 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US6290637B1 (en) * | 1999-07-16 | 2001-09-18 | University Of New Hampshire | Phosphate mineral-based reactive barrier containment system |
| JP2002153850A (en) * | 2000-11-17 | 2002-05-28 | Koken Boring Mach Co Ltd | Method for immobilizing contaminated soil |
| JP2004298831A (en) * | 2003-04-01 | 2004-10-28 | Onoda Chemico Co Ltd | Method for confining contaminated soil and structure body containing contaminated soil |
| FR2912396B1 (en) * | 2007-02-09 | 2011-08-26 | Solvay | PROCESS FOR PRODUCING A PHOSPHOCALCIUM REAGENT, REAGENT OBTAINED AND USE THEREOF |
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