JPH11347531A - Method for improving soil contaminated by hexavalent chromium - Google Patents
Method for improving soil contaminated by hexavalent chromiumInfo
- Publication number
- JPH11347531A JPH11347531A JP10162245A JP16224598A JPH11347531A JP H11347531 A JPH11347531 A JP H11347531A JP 10162245 A JP10162245 A JP 10162245A JP 16224598 A JP16224598 A JP 16224598A JP H11347531 A JPH11347531 A JP H11347531A
- Authority
- JP
- Japan
- Prior art keywords
- soil
- hexavalent chromium
- sludge
- peat
- contaminated
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Processing Of Solid Wastes (AREA)
- Fire-Extinguishing Compositions (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、六価クロムに汚染
された土壌を安全性の高い土壌に改良する方法に関する
ものである。TECHNICAL FIELD The present invention relates to a method for improving soil contaminated with hexavalent chromium into highly safe soil.
【０００２】[0002]
【従来の技術】近年、都市再開発による工場跡地等で汚
染土壌が生じることがある。土壌汚染成分のうち、六価
クロムの基準値（平成５年に改正された「土壌汚染に係
る環境基準について（環境庁公示第４６号）」の許容溶
出濃度）は、０．０５ｍｇ／Ｌ以下と、埋立処分の基準
値１．５ｍｇ／Ｌ以下に比べてかなり厳しいことから、
その溶出防止対策が重要となる。2. Description of the Related Art In recent years, contaminated soil may be generated on a site of a factory due to urban redevelopment. Among the soil contaminants, the standard value of hexavalent chromium (permissible elution concentration of “Environmental Standards for Soil Contamination Revised in 1993 (Environment Agency Notification No. 46)”) is 0.05 mg / L or less. And it is considerably stricter than the landfill disposal standard of 1.5 mg / L or less.
It is important to take measures to prevent such elution.
【０００３】従来、六価クロムに汚染された土壌からの
六価クロムの溶出を防止する処理として、硫酸第一鉄な
どの還元剤を用いて六価クロムを安全な三価のクロムに
還元処理することが行われている。[0003] Conventionally, as a treatment for preventing the elution of hexavalent chromium from soil contaminated with hexavalent chromium, reduction treatment of hexavalent chromium into safe trivalent chromium using a reducing agent such as ferrous sulfate. That is being done.
【０００４】[0004]
【発明が解決しようとする課題】還元剤による処理で
は、還元剤が酸素と反応するため十分な安全な還元が行
われにくい。また、汚染土壌が広範囲にわたる場合、大
量の還元剤が必要となり、コストが増大する等の問題が
ある。In the treatment with the reducing agent, the reducing agent reacts with oxygen, so that it is difficult to perform a sufficient safe reduction. In addition, when the contaminated soil covers a wide area, there is a problem that a large amount of a reducing agent is required and the cost is increased.
【０００５】本発明は、上記従来の問題点を解決し、六
価クロムに汚染された土壌を安全かつ安価に処理して六
価クロムの溶出量を低減することができる六価クロム汚
染土壌の改良方法を提供することを目的とする。[0005] The present invention solves the above-mentioned conventional problems and provides a method for treating hexavalent chromium-contaminated soil safely and inexpensively to reduce hexavalent chromium-contaminated soil. It is intended to provide an improved method.
【０００６】[0006]
【課題を解決するための手段】本発明の六価クロム汚染
土壌の改良方法は、六価クロムに汚染された土壌に、ヘ
ドロ、黒ぼく土及びピートよりなる群から選ばれる１種
又は２種以上を添加混合して六価クロムの溶出量を低減
させることを特徴とする。According to the present invention, there is provided a method for improving hexavalent chromium-contaminated soil, comprising the steps of: adding, to a soil contaminated with hexavalent chromium, one or two species selected from the group consisting of sludge, black soil and peat; It is characterized by adding and mixing the above to reduce the elution amount of hexavalent chromium.
【０００７】このヘドロは、河川底、湖底、沿岸海底
（例えば港湾底）に堆積した泥状堆積物である。黒ぼく
土は火山灰が腐植集積作用を受けて生じた土壌である。
ピートは、鉱物性の土粒子を殆ど含まない植物性の有機
質土である。[0007] The sludge is a muddy sediment deposited on the bottom of a river, the bottom of a lake, or the bottom of a coastal sea (for example, the bottom of a port). Kuroboku soil is the soil produced by the humus accumulation of volcanic ash.
Pete is a vegetable organic soil that contains few mineral soil particles.
【０００８】本発明では、従来、廃棄処分されているヘ
ドロや火山灰土の黒ぼく土（アンドソル）やピート（高
有機質土）を還元剤として利用し、土壌中の六価クロム
を三価のクロムに還元する。この還元作用機構の詳細は
明らかではないが、ヘドロや黒ぼく土やピートに含まれ
る有機分が六価クロムを三価に還元する還元作用を奏す
るものと考えられる。[0008] In the present invention, black soil (Andsol) or peat (highly organic soil) of sludge or volcanic ash which has been conventionally disposed of is used as a reducing agent, and hexavalent chromium in the soil is converted to trivalent chromium. To be reduced to Although the details of this reduction mechanism are not clear, it is considered that the organic components contained in sludge, black sand and peat have a reduction action of reducing hexavalent chromium to trivalent.
【０００９】本発明の実施には、従来、一般の地盤改良
工事に使用されている施工機械を使用することができ、
更に、土質改良用固化材等の硬化促進剤や水と一緒に混
合することで良好な改良地盤を構築することができる。In the practice of the present invention, construction machines conventionally used for general ground improvement work can be used.
Furthermore, a good improved ground can be constructed by mixing with a hardening accelerator such as a solidifying material for soil improvement and water.
【００１０】[0010]
【発明の実施の形態】以下に本発明の実施の形態を詳細
に説明する。Embodiments of the present invention will be described below in detail.
【００１１】本発明においては、六価クロムに汚染され
た土壌にヘドロ、黒ぼく土及びピートよりなる群から選
ばれる１種又は２種以上を添加混合するが、特に、ヘド
ロ、黒ぼく土及びピートのうちの１種又は２種以上と共
に適当な硬化促進剤を併用添加するのが好ましく、これ
により強度発現性を高め、良好な改良地盤を構築するこ
とが可能となる。In the present invention, one or more selected from the group consisting of sludge, black soil and peat are added to and mixed with hexavalent chromium-contaminated soil. It is preferable to add an appropriate hardening accelerator together with one or more of the peats, whereby it is possible to enhance strength development and to construct a good improved ground.
【００１２】この硬化促進剤としては、一般的な軟弱土
壌用のセメント系土質安定材等を用いることができる。As the hardening accelerator, a general cement-based soil stabilizer for soft soil can be used.
【００１３】本発明において、汚染土壌へのヘドロ、黒
ぼく土及びピートのうちの１種又は２種以上や硬化促進
剤の添加割合は、予め実験室において配合試験を行って
試料からの六価クロムの溶出量や試料の強度を調べるこ
とにより、好適な範囲に設定することができる。In the present invention, the addition ratio of one or more of sludge, andosol and peat to contaminated soil and the addition ratio of a hardening accelerator are determined in advance by performing a mixing test in a laboratory, and By examining the elution amount of chromium and the strength of the sample, it can be set to a suitable range.
【００１４】ヘドロ、黒ぼく土及びピートのうちの１種
又は２種以上や硬化促進剤は、汚染土壌に対して乾式添
加しても良く、また、これらを水に加えてスラリーとし
て湿式添加しても良く、いずれの場合においても、通常
の地盤改良工事に使用される施工機械を用いて汚染土壌
を掘削し、現場にてヘドロ、黒ぼく土及びピートのうち
の１種又は２種以上、更に必要に応じて硬化促進剤を添
加混合した後、埋め戻すことにより、容易に実施するこ
とができる。なお、特にヘドロ、黒ぼく土及びピートの
うちの１種又は２種以上を湿式添加する場合、ヘドロ、
黒ぼく土及びピートのうちの１種又は２種以上を篩にか
けて粒径の大きな礫を予め取り除いておくことが望まし
い。One or more of sludge, andosol and peat or a hardening accelerator may be added dry to contaminated soil, or they may be added to water and wet added as a slurry. In any case, in any case, the contaminated soil is excavated using a construction machine used for ordinary ground improvement work, and one or more of sludge, black soil and peat at the site, Further, the method can be easily carried out by adding and mixing a curing accelerator as needed and then backfilling. In particular, when one or more of sludge, black soil and peat are wet-added, sludge,
It is desirable to sieve one or more of black soil and peat to remove large-size gravels in advance.
【００１５】前述の如く、汚染土壌に対するヘドロ、黒
ぼく土及び／又はピートや硬化促進剤の添加量は、汚染
土壌の汚染の程度や、ヘドロ、黒ぼく土及び／又はピー
トの産地、硬化促進剤の性能等により異なるため、予め
予備実験を行って適宜設定するのが好ましいが、一般的
には、汚染土壌１ｍ3に対して、ヘドロ、黒ぼく土及び
ピートの１種又は２種以上を０．０１〜０．５ｍ3程
度、硬化促進剤を１００〜３００ｋｇ程度添加混合する
ことにより、良好な六価クロムの溶出防止効果及び強度
発現性を得ることができる。As described above, the amount of sludge, black soil and / or peat or hardening accelerator added to the contaminated soil depends on the degree of contamination of the contaminated soil, the place of production of sludge, black sand and / or peat, and the acceleration of hardening. Since it depends on the performance of the agent and the like, it is preferable to perform preliminary experiments in advance and set appropriately. In general, one or more of sludge, black soil and peat are used for 1 m 3 of contaminated soil. 0.01 to 0.5M 3 mm, a curing accelerator by adding mixing about 100 to 300, it is possible to obtain the elution preventing effect and strength development of good hexavalent chromium.
【００１６】なお、本発明においては、必要に応じて更
に硫酸第一鉄等の通常の六価クロム汚染土壌の処理に用
いられている還元剤を併用しても良く、還元剤を併用す
ることにより、六価クロムの溶出量をより一層低減する
ことができる。この場合、還元剤の必要添加量も予め予
備実験を行うことにより、容易に決定することができ
る。In the present invention, if necessary, a reducing agent such as ferrous sulfate used for the treatment of ordinary hexavalent chromium-contaminated soil may be used in combination. Thereby, the elution amount of hexavalent chromium can be further reduced. In this case, the required addition amount of the reducing agent can be easily determined by conducting preliminary experiments in advance.
【００１７】［実施例］以下に実施例及び比較例を挙げ
て本発明をより具体的に説明する。[Examples] The present invention will be more specifically described below with reference to examples and comparative examples.
【００１８】実施例１〜５、比較例１ 六価クロムに汚染された土壌（湿潤密度１．５５ｇ／ｃ
ｍ3、六価クロムの溶出量０．２２ｍｇ／Ｌ）１ｍ3に対
し、水に一般軟弱用セメント系土質安定材「スタビライ
ト」（三菱マテリアル（株）製）とヘドロ、黒ぼく土又
はピートを表１に示す割合で加えたスラリーを添加混合
して（ただし、比較例１ではヘドロ、黒ぼく土及びピー
ト添加せず。）供試体を作製し、材齢７日の一軸圧縮強
さと六価クロム溶出量を調べ、結果を表１に示した。こ
れらのヘドロは表中に示す地名の港湾底の浚渫物であ
る。また、黒ぼく土の産地は神奈川県厚木市産であり、
ピートは千葉県野田市産である。Examples 1 to 5, Comparative Example 1 Soil contaminated with hexavalent chromium (wet density 1.55 g / c
m 3 , hexavalent chromium elution amount 0.22 mg / L) For 1 m 3, add water-based cement-based soil stabilizer “Stabilite” (manufactured by Mitsubishi Materials Corporation) to water and sludge, black soil or peat. Was added in the ratio shown in Table 1 (however, sludge, black clay and peat were not added in Comparative Example 1) to prepare a specimen, and the uniaxial compressive strength and the six-day compressive strength of 7 days were obtained. The elution amount of chromium (V) was examined, and the results are shown in Table 1. These sludges are dredged on the bottom of the port with the name shown in the table. Kuroboku soil is produced in Atsugi City, Kanagawa Prefecture,
Pete is from Noda City, Chiba Prefecture.
【００１９】[0019]
【表１】 [Table 1]
【００２０】表１より、本発明によれば、ヘドロ、黒ぼ
く土又はピートを用いることにより、六価クロムに汚染
された土壌を安価に処理して六価クロムの溶出量を環境
基準値の０．０５ｍｇ／Ｌ以下に低減することができる
ことが明らかである。また、土質安定材の併用で強度を
高め、良好な地盤を構築することができることもわか
る。According to Table 1, according to the present invention, the use of sludge, black clay or peat makes it possible to inexpensively treat soil contaminated with hexavalent chromium and determine the amount of hexavalent chromium eluted as an environmental standard value. It is clear that it can be reduced to 0.05 mg / L or less. In addition, it can be seen that the strength can be increased by using the soil stabilizer in combination, and a good ground can be constructed.
【００２１】[0021]
【発明の効果】以上詳述した通り、本発明の六価クロム
汚染土壌の改良方法によれば、六価クロムに汚染された
土壌を安価に処理して六価クロムの溶出量を低減するこ
とができる。特に、請求項２の方法によれば、良好な改
良地盤を構築することができる。As described above, according to the method for improving hexavalent chromium-contaminated soil according to the present invention, the amount of hexavalent chromium contaminated is reduced by treating the soil contaminated with hexavalent chromium at low cost. Can be. In particular, according to the method of claim 2, it is possible to construct a favorable improved ground.
Claims (2)
ロ、黒ぼく土及びピートよりなる群から選ばれる１種又
は２種以上を添加混合して六価クロムの溶出量を低減さ
せることを特徴とする六価クロム汚染土壌の改良方法。1. A method for reducing the amount of hexavalent chromium eluted by adding one or more selected from the group consisting of sludge, black soil and peat to soil contaminated with hexavalent chromium. Characteristic method for improving hexavalent chromium-contaminated soil.
しくは硬化促進剤と水のスラリーを添加混合することを
特徴とする六価クロム汚染土壌の改良方法。2. The method for improving hexavalent chromium-contaminated soil according to claim 1, further comprising adding and mixing a curing accelerator or a slurry of the curing accelerator and water.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10162245A JPH11347531A (en) | 1998-06-10 | 1998-06-10 | Method for improving soil contaminated by hexavalent chromium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10162245A JPH11347531A (en) | 1998-06-10 | 1998-06-10 | Method for improving soil contaminated by hexavalent chromium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH11347531A true JPH11347531A (en) | 1999-12-21 |
Family
ID=15750762
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10162245A Pending JPH11347531A (en) | 1998-06-10 | 1998-06-10 | Method for improving soil contaminated by hexavalent chromium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH11347531A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003093538A (en) * | 2001-09-26 | 2003-04-02 | Taiheiyo Cement Corp | Reduction method of hexavalent chrome by particle-size control of silicon |
| KR20030053231A (en) * | 2001-12-22 | 2003-06-28 | 재단법인 포항산업과학연구원 | Permeable reactive barrier containing peat and remediation of contaminants in groundwater using the same |
| JP2005254082A (en) * | 2004-03-10 | 2005-09-22 | Nippon Steel & Sumikin Stainless Steel Corp | Method for controlling elution of hexavalent chromium from steel slug and material for land burial of the slug |
| JP2006263509A (en) * | 2005-03-22 | 2006-10-05 | Chugoku Electric Power Co Inc:The | Method for fixing substance easily eluted in water, and material obtained by it |
-
1998
- 1998-06-10 JP JP10162245A patent/JPH11347531A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003093538A (en) * | 2001-09-26 | 2003-04-02 | Taiheiyo Cement Corp | Reduction method of hexavalent chrome by particle-size control of silicon |
| KR20030053231A (en) * | 2001-12-22 | 2003-06-28 | 재단법인 포항산업과학연구원 | Permeable reactive barrier containing peat and remediation of contaminants in groundwater using the same |
| JP2005254082A (en) * | 2004-03-10 | 2005-09-22 | Nippon Steel & Sumikin Stainless Steel Corp | Method for controlling elution of hexavalent chromium from steel slug and material for land burial of the slug |
| JP2006263509A (en) * | 2005-03-22 | 2006-10-05 | Chugoku Electric Power Co Inc:The | Method for fixing substance easily eluted in water, and material obtained by it |
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