JP5541986B2 - How to clean the soil - Google Patents

How to clean the soil Download PDF

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JP5541986B2
JP5541986B2 JP2010153507A JP2010153507A JP5541986B2 JP 5541986 B2 JP5541986 B2 JP 5541986B2 JP 2010153507 A JP2010153507 A JP 2010153507A JP 2010153507 A JP2010153507 A JP 2010153507A JP 5541986 B2 JP5541986 B2 JP 5541986B2
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soil
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信一 中村
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株式会社オメガ
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この発明は、公害を引き起こす物質である精錬所やめっき工場等から排出されるベンゼンや、六価クロム、鉛、水銀、フッ素、砒素等の重金属類等で汚染された土壌、ドライクリーニングや金属の洗浄に用いられているテトラクロロエチレン等の有害物質で汚染された土壌、A重油などの漏洩油その他によって汚染された土壌の洗浄方法に関するものである。   This invention is applicable to soil contaminated with heavy metals such as benzene, hexavalent chromium, lead, mercury, fluorine, arsenic, etc. discharged from smelters and plating plants, which are substances that cause pollution, dry cleaning and metal The present invention relates to a method for cleaning soil contaminated with harmful substances such as tetrachloroethylene used for cleaning, soil contaminated with leaked oil such as heavy oil A, and the like.

従来、公害を引き起こす物質である精錬所やめっき工場等から排出される六価クロムやベンゼン、または鉛、水銀等の重金属で汚染された土壌、あるいはドライクリーニングや金属の洗浄に用いられているテトラクロロエチレン等の有害物質に汚染されている土壌を、そのまま原位置において、汚染土壌の土粒子を洗浄して汚染土壌を処理する汚染土壌の処理方法に関する提案があった(特許文献1)。
すなわち、各種産業の工場敷地内または工場設備から漏洩した公害汚染物質が工場周辺に流失または地下に浸透して周辺地域の土壌を汚染した場合、あるいは産業廃棄物から浸出した有害物質によって土壌が汚染された場合、従来は汚染土壌を取り除き新しい土壌に置き換えるなどの方法が施工されているところ、例えば細粒土で構成されている埋立地の工業地帯等ではその構成されている地盤は極めて小さい土粒子の土壌から成っている地域であり、その土の透水係数は低いことなどが記載されている。
しかし、前記のような小さい土粒子を含む土壌を液相中で洗浄しようとすると、粒子径のある程度大きな礫はそのうちに沈降するものの、粒子径の小さい粘土やシルト質は液中に分散した状態となって液相との分離が困難であるという問題があった。
特開2010−12445号公報
Conventionally, soil contaminated with hexavalent chromium, benzene, or heavy metals such as lead, mercury, etc. discharged from smelters and plating plants that cause pollution, or tetrachlorethylene used for dry cleaning and metal cleaning There has been a proposal relating to a method for treating contaminated soil in which soil contaminated with harmful substances such as the above is directly in situ, and the soil particles of the contaminated soil are washed to treat the contaminated soil (Patent Document 1).
In other words, pollution pollutants leaked from factory premises or factory equipment of various industries are washed away or penetrated underground to contaminate the soil in the surrounding area, or soil is contaminated by harmful substances leached from industrial waste. In the past, methods such as removing contaminated soil and replacing it with new soil have been constructed.For example, in the industrial area of landfills composed of fine-grained soil, the ground that is constructed is extremely small soil. It is an area made up of particle soil, and the soil has a low hydraulic conductivity.
However, when the soil containing small soil particles as described above is washed in the liquid phase, gravel with a certain size of particles settles over time, but small particles of clay and silt are dispersed in the solution. Thus, there is a problem that separation from the liquid phase is difficult.
JP 2010-12445 A

そこでこの発明は、小さな粒子径の成分を有する土壌であっても好適に洗浄することができる土壌の洗浄方法を提供しようとするものである。   Therefore, the present invention intends to provide a soil washing method that can suitably wash even soil having a small particle size component.

前記課題を解決するためこの発明では次のような技術的手段を講じている。
(1)この発明の土壌の洗浄方法は、土壌を洗浄して汚れ成分を溶出させる洗浄工程と、前記土壌の洗浄水中の小さな粒子径の土壌成分を凝集・沈殿させる沈降分離工程とを有することを特徴とする。
この土壌の洗浄方法では、土壌を洗浄して汚れ成分を溶出させる洗浄工程を有するが、前記汚れ成分としてベンゼンや、ドライクリーニングや金属の洗浄に用いられているテトラクロロエチレン等の有害物質その他の有機化合物、六価クロム、鉛、水銀、フッ素、砒素等の重金属類等、A重油などの漏洩油を例示することができる。
前記洗浄水は、酸を添加して酸性にすると重金属類の溶出が促進することとなり、電解次亜塩素酸などの酸化剤を添加すると有機化合物の分解が促進することとなり、電解水を添加すると・OHラジカルなどの活性種によって有機化合物の分解がいちじるしく促進されることとなる。
In order to solve the above problems, the present invention takes the following technical means.
(1) The soil washing method of the present invention includes a washing step for washing soil to elute soil components, and a sedimentation separation step for agglomerating and precipitating soil components having a small particle size in the soil washing water. It is characterized by.
This soil washing method has a washing step of washing the soil and eluting the dirt component. As the dirt component, benzene, harmful substances such as tetrachlorethylene used for dry cleaning and metal washing, and other organic compounds Examples of such oils include heavy metals such as hexavalent chromium, lead, mercury, fluorine, and arsenic, and heavy oil such as heavy oil A.
When the washing water is acidified by adding an acid, elution of heavy metals is promoted, and when an oxidizing agent such as electrolytic hypochlorous acid is added, the decomposition of the organic compound is promoted.・ Decomposition of organic compounds is greatly accelerated by active species such as OH radicals.

そして、土壌の洗浄水中の小さな粒子径の土壌成分を凝集・沈殿させる沈降分離工程を有するので、分散している小さな粒子径の成分(負イオンに帯電した土粒子同士が反発し合って分散・安定していると推測される)を洗浄水から分離して処理(脱水、乾燥など)することができる。
ここで、前記小さな粒子径の土壌成分を凝集・沈殿させるための凝集剤としてPACなどを用いることができる。また、土壌の土粒子サイズについて0.002mm未満は粘土、0.002〜0.02mmはシルト、0.02〜0. 2mmは細砂、0. 2〜2mmは粗砂、2mm以上は礫と呼ばれるが、凝集・沈殿させる「土壌の洗浄水中の小さな粒子径」は土壌の性状(含有される粒子径分布など)、沈降時間、凝集させる際に用いる凝集剤の種類などの相対的な関係で決まるものであって、数字で一概に決められるものではないが、そのままでは沈降しにくい粒子径であるが凝集・沈殿させることにより沈降分離することができる粒子径ということができる。
そして、前記沈降分の土壌成分を脱水する脱水工程を有することとすると、汚れ成分が洗浄され脱水されて清浄化した土壌を再生することができる。
And since it has a sedimentation separation process that agglomerates and precipitates the soil components with small particle size in the soil wash water, the dispersed small particle size components (the negatively charged soil particles repel each other Can be separated from the wash water and treated (dehydrated, dried, etc.).
Here, PAC or the like can be used as an aggregating agent for aggregating and precipitating the soil component having a small particle diameter. Also, the soil particle size of soil is called clay for less than 0.002mm, silt for 0.002 to 0.02mm, fine sand for 0.02 to 0.2mm, coarse sand for 0.2 to 2mm, and gravel for more than 2mm. “Small particle size in soil wash water” is determined by relative relationships such as soil properties (particle size distribution, etc.), sedimentation time, type of flocculant used for agglomeration, Although it is not generally determined by numbers, it can be said that it is a particle diameter that is difficult to settle as it is, but can be precipitated and separated by aggregation and precipitation.
And if it has the dehydration process which spin-dry | dehydrates the soil component of the said sediment, the soil component was wash | cleaned and dehydrated and cleaned soil can be reproduced | regenerated.

(2) 重金属類等で汚染された土壌の洗浄方法であって、前記沈降分離工程における土壌成分の沈降分を引き出し加熱媒体に及ぼして焼成する焼成工程を有し、前記焼成工程では土壌成分の沈降分が焼成されて生成したスラグに重金属類等を封じ込めて不溶化するようにしてもよい。
ここで、沈降分離工程における土壌成分の沈降分は、例えばポンプなどで引き出して焼成工程における焼成炉内に供給することができる。また、前記加熱媒体としてアルミナ粒子、食塩粒子、溶融食塩、低融点合金などを例示することができる。
ところで、小さな粒子径の土壌成分(例えば粘土やシルト)に吸着した重金属類等はかなり強固に吸着していて溶出させることは困難であるところ、焼成工程では土壌成分の沈降分が焼成(例えば1300℃)されて生成したスラグに重金属類等を封じ込めて不溶化するようにしたので、重金属類等で汚染された小さな粒子径の土壌成分をスラグ等にして有効に再利用することができる。
なお、土壌成分中の有機物が焼成されてなる灰や、土壌成分中の無機物が焼成されてなるカリ成分は焼成時にスラグ中に一体化されることとなる。
(2) A method for cleaning soil contaminated with heavy metals and the like, comprising a baking step of extracting and precipitating the sediment content of the soil component in the sedimentation separation step on a heating medium, You may make it insolubilize by containing heavy metals etc. in the slag produced | generated by baking the sediment.
Here, the sediment content of the soil component in the sedimentation separation process can be drawn out with a pump or the like, for example, and supplied to the firing furnace in the firing process. Examples of the heating medium include alumina particles, salt particles, molten salt, and a low melting point alloy.
By the way, heavy metals adsorbed on soil components having a small particle size (for example, clay and silt) are adsorbed fairly firmly and are difficult to elute. Since the heavy metals and the like are contained in the slag generated by the heat treatment and insolubilized, the soil component having a small particle diameter contaminated with the heavy metals and the like can be effectively reused as the slag.
In addition, the ash formed by baking the organic substance in the soil component and the potash component formed by baking the inorganic substance in the soil component are integrated into the slag at the time of baking.

(3)前記洗浄工程においてサイクロン機構により粒子径の大きな土壌成分を遠心分離するようにしてもよい。
このように構成すると、洗浄水から先ず土壌の粒子径の大きな成分(例えば粒径2mm以上の礫)を分離することができ、その後にこの洗浄水を沈降分離工程へと移行させることができる。
(3) The soil component having a large particle size may be centrifuged by the cyclone mechanism in the washing step.
If comprised in this way, the component (for example, gravel with a particle size of 2 mm or more) of a soil particle | grain large first can be isolate | separated from wash water, and this wash water can be made to transfer to a sedimentation separation process after that.

(4)前記加熱流体としてアルミナ粒子を用いるようにしてもよい。
アルミナは比熱が低い(0.19cal/g・℃)性質を有するので、焼成工程における加熱・昇温時のエネルギー効率に優れることとなる。また、また、アルミナ粒子の比重は約4.0であり、土壌の構成成分が焼成されてなるスラグ(比重3)と比重差により相互を分離することができる。
(4) Alumina particles may be used as the heating fluid.
Since alumina has a property of low specific heat (0.19 cal / g · ° C.), it is excellent in energy efficiency at the time of heating / heating in the firing process. Moreover, the specific gravity of the alumina particles is about 4.0, and can be separated from the slag (specific gravity 3) obtained by firing the constituent components of the soil by the specific gravity difference.

(5)前記土壌成分の沈降分を生石灰に遭遇させるようにしてもよい。
このように構成すると、未だ保水している土壌成分の沈降分の水分を生石灰が吸水して消石灰に化学変化して減水することとなるので、焼成工程における加熱エネルギーを減水した分だけ節約することができる。
ここで、焼成工程において消石灰の分解温度である580℃以上に加熱するとCa(OH)2→CaOと化学変化して生石灰を再生することができる。そして、再生した生石灰は再度土壌成分の沈降分の水分の低減に利用することができる。
(5) You may make it encounter quicklime with the sediment of the said soil component.
When configured in this way, the quick lime absorbs the moisture of the sediment component of the soil component that is still water-retained and chemically changes to slaked lime to reduce the water, so the heating energy in the firing process is saved by the amount reduced. Can do.
Here, when heated to 580 ° C. or more, which is the decomposition temperature of slaked lime, in the firing step, quick lime can be regenerated by chemically changing Ca (OH) 2 → CaO. And the regenerated quicklime can be utilized again for the reduction | decrease of the water | moisture content of the sediment of a soil component.

(6)洗浄水中の小さな粒子径の土壌成分を凝集・沈殿させた後の上澄み液の方は、電気分解などによって浄化して清浄化することができる。 (6) The supernatant liquid after agglomerating and precipitating soil components having a small particle diameter in the wash water can be purified and purified by electrolysis or the like.

(7)前記上澄み液に生石灰を遭遇させてその水分を低減させ、次いで580℃以上に加熱して消石灰を生石灰を再生することもできる。
上澄み液の生石灰への遭遇は電気分解による清浄化の後でもよいし、電気分解による清浄化を行わずにそのまま行ってもよい。
(7) Quick lime can be made to encounter the said supernatant liquid, the water | moisture content can be reduced, and it can also heat above 580 degreeC, and can also reproduce quick lime.
The encounter of the supernatant liquid with quicklime may be performed after the cleaning by electrolysis or may be performed without performing the cleaning by electrolysis.

この発明は上述のような構成であり、次の効果を有する。
小さな粒子径の成分を洗浄水から分離して処理することができるので、小さな粒子径の成分を有する土壌であっても好適に洗浄することができる土壌の洗浄方法を提供することができる。
The present invention is configured as described above and has the following effects.
Since a component having a small particle diameter can be separated from the washing water and treated, a soil cleaning method that can suitably wash even soil having a component having a small particle diameter can be provided.

以下、この発明の実施の形態を説明する。
(実施形態1)
この実施形態の土壌の洗浄方法は、土壌を洗浄して汚れ成分を溶出させる洗浄工程と、前記土壌の洗浄水中の小さな粒子径の土壌成分を凝集・沈殿させる沈降分離工程とを有する。
この土壌の洗浄方法では、土壌を洗浄して汚れ成分を溶出させる洗浄工程を有するが、前記汚れ成分としてベンゼンや、ドライクリーニングや金属の洗浄に用いられているテトラクロロエチレン等の有害物質その他の有機化合物、六価クロム、鉛、水銀、フッ素、砒素等の重金属類等、A重油などの漏洩油を例示することができる。
前記洗浄水は、酸を添加して酸性にすると重金属類の溶出が促進することとなり、電解次亜塩素酸などの酸化剤を添加すると有機化合物の分解が促進することとなり、電解水を添加すると・OHラジカルなどの活性種によって有機化合物の分解がいちじるしく促進されることとなる。
Embodiments of the present invention will be described below.
(Embodiment 1)
The soil washing method of this embodiment includes a washing step for washing soil to elute soil components, and a sedimentation separation step for agglomerating and precipitating soil components having a small particle diameter in the soil washing water.
This soil washing method has a washing step of washing the soil and eluting the dirt component. As the dirt component, benzene, harmful substances such as tetrachlorethylene used for dry cleaning and metal washing, and other organic compounds Examples of such oils include heavy metals such as hexavalent chromium, lead, mercury, fluorine, and arsenic, and heavy oil such as heavy oil A.
When the washing water is acidified by adding an acid, elution of heavy metals is promoted, and when an oxidizing agent such as electrolytic hypochlorous acid is added, the decomposition of the organic compound is promoted.・ Decomposition of organic compounds is greatly accelerated by active species such as OH radicals.

次に、この実施形態の土壌の洗浄方法の使用状態を説明する。
土壌の洗浄水中の小さな粒子径の土壌成分を凝集・沈殿させる沈降分離工程を有するので、分散している小さな粒子径の成分(負イオンに帯電した土粒子同士が反発し合って分散・安定していると推測される)を洗浄水から分離して処理(脱水、乾燥など)することができ、小さな粒子径の成分を有する土壌であっても好適に洗浄することができるという利点を有する。
Next, the usage state of the soil cleaning method of this embodiment will be described.
Since it has a sedimentation process that aggregates and precipitates soil components of small particle size in the soil washing water, the dispersed small particle size components (the negatively charged soil particles repel each other and disperse and stabilize. Can be separated from the washing water for treatment (dehydration, drying, etc.), and even soil having a small particle size component can be suitably washed.

ここで、前記小さな粒子径の土壌成分を凝集・沈殿させるための凝集剤としてPACなどを用いることができる。また、土壌の土粒子サイズについて0.002mm未満は粘土、0.002〜0.02mmはシルト、0.02〜0. 2mmは細砂、0. 2〜2mmは粗砂、2mm以上は礫と呼ばれるが、凝集・沈殿させる「土壌の洗浄水中の小さな粒子径」は土壌の性状(含有される粒子径分布など)、沈降時間、凝集させる際に用いる凝集剤の種類などの相対的な関係で決まるものであって、数字で一概に決められるものではないが、そのままでは沈降しにくい粒子径であるが凝集・沈殿させることにより沈降分離することができる粒子径ということができる。
なお、沈降分は元の土壌洗浄水の容量の30分の1程度の容量となり、減容化することができ、脱水成工程における省エネ効率に優れるものであった。
そして、前記沈降分の土壌成分を脱水する脱水工程を有することとすると、汚れ成分が洗浄され脱水されて清浄化した土壌を再生することができる。
Here, PAC or the like can be used as an aggregating agent for aggregating and precipitating the soil component having a small particle diameter. Also, the soil particle size of soil is called clay for less than 0.002mm, silt for 0.002 to 0.02mm, fine sand for 0.02 to 0.2mm, coarse sand for 0.2 to 2mm, and gravel for more than 2mm. “Small particle size in soil wash water” is determined by relative relationships such as soil properties (particle size distribution, etc.), sedimentation time, type of flocculant used for agglomeration, Although it is not generally determined by numbers, it can be said that it is a particle diameter that is difficult to settle as it is, but can be precipitated and separated by aggregation and precipitation.
The sediment content was about 1/30 of the original soil washing water volume, and the volume could be reduced, resulting in excellent energy saving efficiency in the dehydration process.
And if it has the dehydration process which spin-dry | dehydrates the soil component of the said sediment, the soil component was wash | cleaned and dehydrated and cleaned soil can be reproduced | regenerated.

(実施形態2)
この実施形態では、前記沈降分離工程における土壌成分の沈降分を引き出し加熱媒体に及ぼして焼成する焼成工程を有し、前記焼成工程では土壌成分の沈降分が焼成されて生成したスラグに重金属類等を封じ込めて不溶化するようにしている。
沈降分離工程における土壌成分の沈降分は、例えばポンプなどで引き出して焼成工程における焼成炉内に供給することができる。また、前記加熱媒体としてアルミナ粒子、食塩粒子、溶融食塩、低融点合金などを例示することができる。
(Embodiment 2)
In this embodiment, there is a firing step in which the sediment component of the soil component in the sedimentation separation step is drawn out and applied to a heating medium, and calcined. In the firing step, heavy metals and the like are generated in the slag generated by firing the sediment component of the soil component. Is contained and insolubilized.
The sediment content of the soil component in the sedimentation separation process can be drawn out by a pump or the like, for example, and supplied to the firing furnace in the firing process. Examples of the heating medium include alumina particles, salt particles, molten salt, and a low melting point alloy.

小さな粒子径の土壌成分(例えば粘土やシルト)に吸着した重金属類等はかなり強固に吸着していて溶出させることは困難であるところ、焼成工程では土壌成分の沈降分が焼成(例えば1300℃)されて生成したスラグに重金属類等を封じ込めて不溶化するようにしたので、重金属類等で汚染された小さな粒子径の土壌成分をスラグ等にして有効に再利用することができるという利点を有する。
なお、土壌成分中の有機物が焼成されてなる灰や、土壌成分中の無機物が焼成されてなるカリ成分は焼成時にスラグ中に一体化されることとなる。
Heavy metals adsorbed on small particle size soil components (such as clay and silt) are adsorbed fairly firmly and difficult to elute, but in the firing process, the sediment content of the soil components is calcined (eg, 1300 ° C) Since the slag thus produced contains heavy metals or the like and is insolubilized, the soil component having a small particle diameter contaminated with heavy metals or the like can be effectively reused as slag or the like.
In addition, the ash formed by baking the organic substance in the soil component and the potash component formed by baking the inorganic substance in the soil component are integrated into the slag at the time of baking.

(実施形態3)
この実施形態では、前記洗浄工程においてサイクロン機構により粒子径の大きな土壌成分を遠心分離するようにしており、洗浄水から先ず土壌の粒子径の大きな成分(例えば粒径2mm以上の礫)を分離することができ、その後にこの洗浄水を沈降分離工程へと移行させることができるという利点を有する。
(Embodiment 3)
In this embodiment, the soil component having a large particle size is centrifuged by the cyclone mechanism in the washing step, and the component having a large particle size of the soil (for example, gravel having a particle size of 2 mm or more) is first separated from the washing water. And has the advantage that the wash water can then be transferred to a sedimentation separation step.

(実施形態4)
この実施形態では、前記加熱流体としてアルミナ粒子を用いるようにしている。アルミナは比熱が低い(0.19cal/g・℃)性質を有するので、焼成工程における加熱・昇温時のエネルギー効率に優れることとなるという利点を有する。また、アルミナ粒子の比重は約4.0であり、土壌の構成成分が焼成されてなるスラグ(比重3)と比重差により相互を分離することができる。
(Embodiment 4)
In this embodiment, alumina particles are used as the heating fluid. Since alumina has a property of low specific heat (0.19 cal / g · ° C.), it has an advantage of being excellent in energy efficiency at the time of heating / heating in the firing process. The specific gravity of the alumina particles is about 4.0, which can be separated from the slag (specific gravity 3) obtained by firing the constituent components of the soil by the specific gravity difference.

(実施形態5)
この実施形態では、土壌成分の沈降分を生石灰に遭遇させるようにしており、未だ保水している土壌成分の沈降分の水分を生石灰が吸水して消石灰に化学変化して減水することとなるので、焼成工程における加熱エネルギーを減水した分だけ節約することができるという利点を有する。
そして、焼成工程において消石灰の分解温度である580℃以上に加熱するとCa(OH)2→CaOと化学変化して生石灰を再生することができる。そして、再生した生石灰は再度土壌成分の沈降分の水分の低減に利用することができる。
洗浄水中の小さな粒子径の土壌成分を凝集・沈殿させた後の上澄み液の方は、電気分解などによって浄化して清浄化することができる。また、前記上澄み液に生石灰を遭遇させてその水分を低減させ、次いで580℃以上に加熱して消石灰を生石灰を再生することもできる。
なお、上澄み液の生石灰への遭遇は電気分解による清浄化の後でもよいし、電気分解による清浄化を行わずにそのまま行ってもよい。
(Embodiment 5)
In this embodiment, quick lime is caused to encounter the sediment component of the soil component, and the quick component lime absorbs the moisture of the sediment component of the soil component that is still retained, and the water is reduced by chemical change to slaked lime. The heating energy in the firing process can be saved by the reduced amount.
And if it heats to 580 degreeC or more which is a decomposition temperature of slaked lime in a baking process, it can regenerate quick lime by making a chemical change with Ca (OH) 2- > CaO. And the regenerated quicklime can be utilized again for the reduction | decrease of the water | moisture content of the sediment of a soil component.
The supernatant liquid after agglomerating and precipitating soil components with small particle diameters in the wash water can be purified and purified by electrolysis or the like. Moreover, quick lime can be made to meet the said supernatant liquid, the water | moisture content can be reduced, and it can also heat above 580 degreeC, and can reproduce quick lime.
In addition, the encounter with quick lime of the supernatant liquid may be performed after cleaning by electrolysis, or may be performed as it is without performing cleaning by electrolysis.

〔実施例1〕
(汚染土壌の試料の作成)
土壌(シルトを用いた)にフッ化ナトリウムを混合・分散することにより汚染土壌の試料を作成した。この土壌試料からの溶出試験を公定法にしたがって行うと、フッ素(F)の溶出量は30mg/Lであった。
(汚染土壌の洗浄)
次に、この土壌試料を洗浄水(水)に浸漬し、酸(硝酸)を添加してpHを2.5に調整した。また、電気分解した電解次亜塩素酸を添加して残留塩素濃度を1100ppmに調整した。このようにすることにより、土壌試料からフッ素を溶出させて洗浄した。
(土壌洗浄水の沈降分離)
この土壌洗浄水にPACを添加してシルトを沈降分離した。シルトの容積は元の土壌洗浄水の約3分の1になった。そして、このシルトを乾燥し公定法にしたがって溶出試験を行うと、フッ素の溶出量は土壌汚染環境基準の0.8mg/L以下の0.5mg/Lに低減していた。
[Example 1]
(Preparation of contaminated soil samples)
A sample of contaminated soil was prepared by mixing and dispersing sodium fluoride in soil (using silt). When the dissolution test from this soil sample was performed according to the official method, the dissolution amount of fluorine (F) was 30 mg / L.
(Cleaning contaminated soil)
Next, this soil sample was immersed in washing water (water), and acid (nitric acid) was added to adjust the pH to 2.5. Electrolyzed electrolytic hypochlorous acid was added to adjust the residual chlorine concentration to 1100 ppm. In this way, fluorine was eluted from the soil sample and washed.
(Sediment wash water sedimentation)
PAC was added to the soil washing water to separate the silt. Silt volume was reduced to about one third of the original soil wash water. And when this silt was dried and the elution test was conducted according to the official method, the elution amount of fluorine was reduced to 0.5 mg / L which is 0.8 mg / L or less of the soil pollution environment standard.

〔実施例1の1〕
(沈降分離分のアルミナ粒子による焼成)
沈降分離したシルト試料を加熱媒体(アルミナ粒子)に及ぼして1300℃で焼成し、生成したスラグに重金属類等を封じ込めて不溶化した。
〔実施例1の2〕
(沈降分離分と生石灰との混合及び焼成)
沈降分離したシルト試料を生石灰に遭遇させ、保水していた水分を蒸発させて減水した。これにより水分のある割合が生石灰から消石灰への化学変化に消費され、水分のある割合が保水したシルト試料と生石灰との混合時の発熱により蒸発した。これを1300℃で焼成し、生成したスラグに重金属類等(フッ素)を封じ込めて不溶化した。そして、焼成後には前記消石灰(比熱0.28)は熱分解して生石灰が再生した。このように、生石灰を用いると沈降分離した土壌を減水することができ、焼成時のエネルギー・コストを削減することができる。
シルトが焼成されて生成したスラグ(比重約3)と消石灰(嵩比重約0.5)とは、比重差を利用し風を及ぼすことにより分離した。
[1 of Example 1]
(Baking with precipitated alumina particles)
The precipitated silt sample was applied to a heating medium (alumina particles) and baked at 1300 ° C., and the resulting slag was encapsulated with heavy metals and insolubilized.
[Example 2-2]
(Mixing and baking of sedimentation and quicklime)
The silt sample that had settled and separated was encountered with quicklime, and the water that had been retained was evaporated to reduce water. As a result, a certain proportion of moisture was consumed in the chemical change from quick lime to slaked lime, and a certain proportion of moisture was evaporated by the heat generated during mixing of the retained silt sample with quick lime. This was fired at 1300 ° C., and the resulting slag was made insoluble by containing heavy metals (fluorine) and the like. And after baking, the slaked lime (specific heat 0.28) was thermally decomposed to regenerate quick lime. Thus, when quick lime is used, the settled and separated soil can be reduced, and the energy cost at the time of baking can be reduced.
The slag (specific gravity of about 3) and slaked lime (bulk specific gravity of about 0.5) produced by burning the silt were separated by applying wind utilizing the difference in specific gravity.

〔実施例1の3〕
(上澄み液と生石灰との混合及び焼成)
沈降分離した際の上澄み液に生石灰に遭遇させ、水分を蒸発させて減水した。これにより水分のある割合が生石灰から消石灰への化学変化に消費され、水分のある割合が上澄み液と生石灰との混合時の発熱により蒸発した。これを850℃で焼成すると、液中に溶解していた重金属類等(フッ素)は焼成により再生した生石灰に吸着された。
[Example 1-3]
(Mixing and baking of supernatant liquid and quicklime)
The supernatant liquid at the time of sedimentation was encountered with quicklime, and the water was evaporated to reduce the water. As a result, a certain proportion of moisture was consumed in the chemical change from quick lime to slaked lime, and a certain proportion of moisture was evaporated by the heat generated when the supernatant liquid and quick lime were mixed. When this was fired at 850 ° C., heavy metals and the like (fluorine) dissolved in the liquid were adsorbed on quicklime regenerated by firing.

〔実施例2〕
(汚染土壌の試料の作成)
土壌(シルトを用いた)に砒素標準液を混合・分散することにより汚染土壌の試料を作成した。この土壌試料からの溶出試験を公定法にしたがって行うと砒素(As)の溶出量は5mg/Lであった。
(汚染土壌の洗浄)
次に、この土壌試料を洗浄水(水)に浸漬し、酸(硝酸)を添加してpHを2.5に調整した。また、電気分解した電解次亜塩素酸を添加して残留塩素濃度を1100ppmに調整した。このようにすることにより、土壌試料から砒素を溶出させて洗浄した。
(土壌洗浄水の沈降分離)
この土壌洗浄水にPACを添加してシルトを沈降分離した。シルトの容積は元の土壌洗浄水の約3分の1になった。そして、このシルトを乾燥し公定法にしたがって溶出試験を行うと、砒素の溶出量は土壌汚染環境基準の0.01mg/L以下に低減していた。
[Example 2]
(Preparation of contaminated soil samples)
Samples of contaminated soil were prepared by mixing and dispersing arsenic standard solution in soil (using silt). When the elution test from this soil sample was conducted according to the official method, the elution amount of arsenic (As) was 5 mg / L.
(Cleaning contaminated soil)
Next, this soil sample was immersed in washing water (water), and acid (nitric acid) was added to adjust the pH to 2.5. Electrolyzed electrolytic hypochlorous acid was added to adjust the residual chlorine concentration to 1100 ppm. In this way, arsenic was eluted from the soil sample and washed.
(Sediment wash water sedimentation)
PAC was added to the soil washing water to separate the silt. Silt volume was reduced to about one third of the original soil wash water. And when this silt was dried and the elution test was conducted according to the official method, the elution amount of arsenic was reduced to 0.01 mg / L or less of the soil contamination environment standard.

〔実施例2の1〕
(沈降分離分のアルミナ粒子による焼成)
沈降分離したシルト試料を加熱媒体(アルミナ粒子)に及ぼして1300℃で焼成し、生成したスラグに重金属類等を封じ込めて不溶化した。
〔実施例2の2〕
(沈降分離分と生石灰との混合及び焼成)
沈降分離したシルト試料を生石灰に遭遇させ、保水していた水分を蒸発させて減水した。これにより水分のある割合が生石灰から消石灰への化学変化に消費され、水分のある割合が保水したシルト試料と生石灰との混合時の発熱により蒸発した。これを1300℃で焼成し、生成したスラグに重金属類等(砒素)を封じ込めて不溶化した。そして、焼成後には前記消石灰(比熱0.28)は熱分解して生石灰が再生した。このように、生石灰を用いると沈降分離した土壌を減水することができ、焼成時のエネルギー・コストを削減することができる。
シルトが焼成されて生成したスラグ(比重約3)と消石灰(嵩比重約0.5)とは、比重差を利用し風を及ぼすことにより分離した。
[Example 1-2]
(Baking with precipitated alumina particles)
The precipitated silt sample was applied to a heating medium (alumina particles) and baked at 1300 ° C., and the resulting slag was encapsulated with heavy metals and insolubilized.
[Example 2-2]
(Mixing and baking of sedimentation and quicklime)
The silt sample that had settled and separated was encountered with quicklime, and the water that had been retained was evaporated to reduce water. As a result, a certain proportion of moisture was consumed in the chemical change from quick lime to slaked lime, and a certain proportion of moisture was evaporated by the heat generated during mixing of the retained silt sample with quick lime. This was fired at 1300 ° C., and the resulting slag was made insoluble by containing heavy metals (arsenic) and the like. And after baking, the slaked lime (specific heat 0.28) was thermally decomposed to regenerate quick lime. Thus, when quick lime is used, the settled and separated soil can be reduced, and the energy cost at the time of baking can be reduced.
The slag (specific gravity of about 3) and slaked lime (bulk specific gravity of about 0.5) produced by burning the silt were separated by applying wind utilizing the difference in specific gravity.

〔実施例2の3〕
(上澄み液と生石灰との混合及び焼成)
沈降分離した際の上澄み液に生石灰に遭遇させ、水分を蒸発させて減水した。これにより水分のある割合が生石灰から消石灰への化学変化に消費され、水分のある割合が上澄み液と生石灰との混合時の発熱により蒸発した。これを850℃で焼成すると、液中に溶解していた重金属類等(砒素)は焼成により再生した生石灰に吸着された。
[Example 2-3]
(Mixing and baking of supernatant liquid and quicklime)
The supernatant liquid at the time of sedimentation was encountered with quicklime, and the water was evaporated to reduce the water. As a result, a certain proportion of moisture was consumed in the chemical change from quick lime to slaked lime, and a certain proportion of moisture was evaporated by the heat generated when the supernatant liquid and quick lime were mixed. When calcined at 850 ° C., heavy metals and the like (arsenic) dissolved in the liquid were adsorbed by quick lime regenerated by calcining.

〔実施例3〕
土壌(シルトを用いた)に鉛標準液を混合・分散することにより汚染土壌の試料を作成した。この土壌試料からの溶出試験を公定法にしたがって行うと鉛(Pb)の溶出量は6mg/Lであった。
次に、この土壌試料を洗浄水(水)に浸漬し、酸(硝酸)を添加してpHを2.5に調整した。また、電気分解した電解次亜塩素酸を添加して残留塩素濃度を1100ppmに調整した。このようにすることにより、土壌試料から鉛を溶出させて洗浄した。
この土壌洗浄水にPACを添加してシルトを沈降分離した。シルトの容積は元の土壌洗浄水の約3分の1になった。そして、このシルトを乾燥し公定法にしたがって溶出試験を行うと、鉛の溶出量は土壌汚染環境基準の0.01mg/L以下に低減していた。
Example 3
A sample of contaminated soil was prepared by mixing and dispersing lead standard solution in soil (using silt). When the dissolution test from this soil sample was conducted according to the official method, the dissolution amount of lead (Pb) was 6 mg / L.
Next, this soil sample was immersed in washing water (water), and acid (nitric acid) was added to adjust the pH to 2.5. Electrolyzed electrolytic hypochlorous acid was added to adjust the residual chlorine concentration to 1100 ppm. In this way, lead was eluted from the soil sample and washed.
PAC was added to the soil washing water to separate the silt. Silt volume was reduced to about one third of the original soil wash water. And when this silt was dried and the elution test was conducted according to the official method, the elution amount of lead was reduced to 0.01 mg / L or less of the soil pollution environment standard.

〔実施例3の1〕
(沈降分離分のアルミナ粒子による焼成)
沈降分離したシルト試料を加熱媒体(アルミナ粒子)に及ぼして1300℃で焼成し、生成したスラグに重金属類等を封じ込めて不溶化した。
〔実施例3の2〕
(沈降分離分と生石灰との混合及び焼成)
沈降分離したシルト試料を生石灰に遭遇させ、保水していた水分を蒸発させて減水した。これにより水分のある割合が生石灰から消石灰への化学変化に消費され、水分のある割合が保水したシルト試料と生石灰との混合時の発熱により蒸発した。これを1300℃で焼成し、生成したスラグに重金属類等(鉛)を封じ込めて不溶化した。そして、焼成後には前記消石灰(比熱0.28)は熱分解して生石灰が再生した。このように、生石灰を用いると沈降分離した土壌を減水することができ、焼成時のエネルギー・コストを削減することができる。
シルトが焼成されて生成したスラグ(比重約3)と消石灰(嵩比重約0.5)とは、比重差を利用し風を及ぼすことにより分離した。
[Example 3-1]
(Baking with precipitated alumina particles)
The precipitated silt sample was applied to a heating medium (alumina particles) and baked at 1300 ° C., and the resulting slag was encapsulated with heavy metals and insolubilized.
[Example 2-2]
(Mixing and baking of sedimentation and quicklime)
The silt sample that had settled and separated was encountered with quicklime, and the water that had been retained was evaporated to reduce water. As a result, a certain proportion of moisture was consumed in the chemical change from quick lime to slaked lime, and a certain proportion of moisture was evaporated by the heat generated during mixing of the retained silt sample with quick lime. This was fired at 1300 ° C., and the resulting slag was insolubilized by containing heavy metals (lead). And after baking, the slaked lime (specific heat 0.28) was thermally decomposed to regenerate quick lime. Thus, when quick lime is used, the settled and separated soil can be reduced, and the energy cost at the time of baking can be reduced.
The slag (specific gravity of about 3) and slaked lime (bulk specific gravity of about 0.5) produced by burning the silt were separated by applying wind utilizing the difference in specific gravity.

〔実施例3の3〕
(上澄み液と生石灰との混合及び焼成)
沈降分離した際の上澄み液に生石灰に遭遇させ、水分を蒸発させて減水した。これにより水分のある割合が生石灰から消石灰への化学変化に消費され、水分のある割合が上澄み液と生石灰との混合時の発熱により蒸発した。これを850℃で焼成すると、液中に溶解していた重金属類等(鉛)は焼成により再生した生石灰に吸着された。
[Example 3-3]
(Mixing and baking of supernatant liquid and quicklime)
The supernatant liquid at the time of sedimentation was encountered with quicklime, and the water was evaporated to reduce the water. As a result, a certain proportion of moisture was consumed in the chemical change from quick lime to slaked lime, and a certain proportion of moisture was evaporated by the heat generated when the supernatant liquid and quick lime were mixed. When this was fired at 850 ° C., heavy metals and the like (lead) dissolved in the liquid were adsorbed on quicklime regenerated by firing.

小さな粒子径の成分を有する土壌であっても好適に洗浄することができることによって、種々の汚染土壌の洗浄の用途に適用することができる。   Even soil having a small particle size component can be suitably washed, so that it can be applied to various contaminated soil washing applications.

Claims (3)

  1. 重金属類で汚染された土壌の洗浄方法であって、土壌を洗浄して汚れ成分を溶出させる洗浄工程と、前記土壌の洗浄水中の小さな粒子径の土壌成分を凝集・沈殿させる沈降分離工程とを有し、前記沈降分離工程における土壌成分の沈降分を引き出して焼成炉内に供給し、前記土壌成分の沈降分を焼成炉内の加熱媒体に供給して焼成する焼成工程を有し、前記焼成工程では土壌成分の沈降分が焼成されて生成したスラグに重金属類を封じ込めて不溶化するようにしたことを特徴とする土壌の洗浄方法。 A method for washing soil contaminated with heavy metals , comprising a washing step for washing soil to elute soil components, and a settling separation step for agglomerating and precipitating soil components having a small particle size in the soil washing water. And having a calcination step of extracting and supplying the sediment component of the soil component in the sedimentation separation step and supplying it to the firing furnace, supplying the sediment component of the soil component to a heating medium in the firing furnace, and firing A method for cleaning soil, characterized in that heavy metals are contained in the slag produced by firing the sediment of the soil component in the process and insolubilized.
  2. 前記洗浄工程においてサイクロン機構により粒子径の大きな土壌成分を遠心分離するようにした請求項1記載の土壌の洗浄方法。   The soil washing method according to claim 1, wherein a soil component having a large particle size is centrifuged by a cyclone mechanism in the washing step.
  3. 前記加熱媒体としてアルミナ粒子を用いるようにした請求項1又は2記載の土壌の洗浄方法。   The method for washing soil according to claim 1 or 2, wherein alumina particles are used as the heating medium.
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