JP2010149042A - Method of remedying contaminated soil zone - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of comprehensively remedying contaminated soil and contaminated water, which enables an inactivation treatment of a contaminated material, an adsorption removal by a specific ore, and a decomposition and removal by bio-bacillus to clear a countermeasure of contaminated soil. <P>SOLUTION: The method of remedying contaminated soil regions includes a pretreatment process of making soil muddy to remove coarse fragments and other untreated materials, an inactivation treatment process of foreskin-fixing heavy metals with a silica component membrane in an aggregate stage in contaminated soil, a decomposition-removal treating process of decomposing an organic substance utilizing bio-bacillus, an adsorption removal treating process of sorbing other heavy metals which are not inactivated and undegradable materials by passing them through a filtration tank, and an aftertreatment process of drying and burying to return the soil from which the contaminated material is removed, and for treated water from which the contaminated material is removed or groundwater from which the contaminated material is removed by the decomposition-removal treating process and the adsorption removal treating process, of returning as clarified water to groundwater area or discharging separately. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is a pollution for obtaining an improved soil and groundwater area by decomposing and removing the contaminant from soil containing volatile organic compounds (VOC) and heavy metals, and groundwater in a specific area. It relates to soil area improvement methods.

  According to Article 5, Paragraph 4 of the Contaminated Soil Countermeasures Law, deregistration of designated designated areas such as factory ruins is subject to the removal of contamination by specific hazardous substances in the soil. It is allowed to do. As this condition, the amount of heavy metals contained in the soil is below the standard, and it is interpreted that the designation will not be canceled unless the specific hazardous substance is not eluted. In addition, devices for cleaning soil and removing harmful substances have been developed for purification, but these devices are effective for sandy soil, but not suitable for clay or humus. In other words, there is a possibility that the soil can be effectively handled only when the content of silty soil is less than 30%, and there is a possibility that the washed polluted water is mixed and diffused into the groundwater. At present, there is no low-cost countermeasure technique for solving these problems. On the other hand, it is considered to improve the contaminated soil in situ, but the heavy metals contained in them are impossible due to the large amount of elements, and only a part of the various organic compounds are bio-fungi. However, the soil was not sufficiently improved. Furthermore, there is a risk of contamination spreading into the soil and groundwater area of the groundwater zone, and it is obliged to provide a shielding wall to prevent this, but technology to improve this groundwater zone and groundwater simultaneously with the soil Was not found. From the above, to date, the entire soil has been generally replaced, and the transported soil has been treated by intermediate treatment or landfilling to the final disposal site, but it has been contaminated by contamination around the disposal site or improper treatment. Is spreading and has become a new environmental problem.

  In addition, as a conventional countermeasure against contaminated soil by biotechnology, there is a purification method as disclosed in Patent Document 1, for example. This technology adds spores of spore-forming bacteria that purify pollutants to polluted soil or / and contaminated groundwater contaminated with pollutants, induces germination, and purifies contaminated soil or / and polluted groundwater, etc. By adding spores of spore-forming bacteria having the resolution of contaminants to be purified to contaminated soil or contaminated groundwater, and inducing germination after reaching many contaminated areas In this method, the pollutant that is the substance to be purified is decomposed.

Moreover, as a countermeasure for improving soil by solidifying sludge using a conventional electrolytic aggregating binder, for example, a hard-to-treat mud soil immediate effect solidifying agent as disclosed in Patent Document 2 exists. This technology improves the sludge soil in a silica-free state to be treated to oxidized healthy soil, and solidifies the sludge quickly, making it difficult to remove and remove sludge significantly. Uses dredged clay immediate effect solidifying agent. That is, this hard clay mud quick-acting solidifying agent is a high-polymerized sodium polyacrylate, diatomaceous earth, A treatment agent such as fly ash is mixed at a predetermined weight ratio.
JP 2008-188510 A JP 2001-104998 A

  However, conventional measures to improve contaminated soil due to biotechnology and insolubilization are not guaranteed long-term safety, and soil contains various contaminants. However, the actual situation is not a comprehensive measure for soil purification. Moreover, because there is no technology for improving the contaminated soil and the contaminated soil existing in the groundwater zone at a low cost, the contaminated soil is buried in the disposal site by excavation and removal. Or, the intermediate process is performed to eliminate the harm, but many examples of inappropriate processes have been discovered. In addition, pollution around the landfill site has become an environmental problem, and the conventional method using total replacement of soil is not preferable in terms of cost and environmental measures.

  Therefore, the present invention was created in view of the existing circumstances as described above, and simultaneously removes adsorption by a specific ore with respect to pollutants contained in soil and groundwater and decomposes and removes by a biofungus. The purpose is to provide a method for improving the contaminated soil area that can comprehensively improve the contaminated soil and the contaminated groundwater to the extent that the Contaminated Soil Countermeasures Act is cleared without having to replace the soil completely. To do.

  In the present invention, the pretreatment process for removing soil and mud and other untreated substances in the soil, and for contaminated soil, heavy metals are fixed in a foreskin with a silica component film in the process of agglomeration. Adsorption by passing through the filter tank the inactivation treatment process to be performed, the decomposition removal treatment process for decomposing organic substances using bio-bacteria, and other heavy metals that have not been inactivated or non-degradable substances Adsorption / removal treatment process and soil from which contaminants have been removed are dried and backfilled, and treated water from which contaminants have been removed by the above-mentioned processes, or groundwater from which contaminants have been removed by decomposition / removal treatment processes and adsorption / removal treatment processes In that case, it is characterized by a method for improving a contaminated soil area comprising a post-treatment step of returning to groundwater as clarified water or draining it separately.

  In addition, the above pretreatment process is performed by adding water to the soil or washing it with a washing / classifying plant so that the soil is concentrated and volume-reduced to become muddy, resulting in gravel, wood, garbage and other untreated substances. It features a method for improving contaminated soil area that removes soil.

  Furthermore, the pre-treatment step involves adding water to the soil or washing it with a washing / classifying plant to make the soil hydrolyzed and mudified in a concentrated and reduced volume, resulting in gravel, wood, garbage, and other untreated substances. At the same time, the soil that has been determined to be non-contaminated by analyzing the soil with an inspection device is classified into the back-treatment process in the post-treatment process, and the one that has been determined to be contaminated soil is classified into the inactivation process. It features a method for improving contaminated soil area.

  In addition, the inactivation treatment process instantly agglomerates by acting on the soil colloid, and at the same time the alkali is neutralized with the strongly alkaline solution A in which heavy metals are encapsulated in the colloid. Contaminated soil area by two-component type with B-solution by neutralization improver (pH adjuster) that makes silica component transform into glass film and completely envelop the entire soil colloid so that it becomes inactive for a long time Features an improvement method.

  Furthermore, the decomposition and removal treatment step is characterized by a method for improving a contaminated soil area in which a floating separation treatment, a contact aeration treatment, and a filtration treatment are sequentially performed, and organic substances due to biofungi are decomposed and removed in the filtration treatment.

  In addition, the adsorption removal treatment step adsorbs other heavy metals that have not been deactivated in the deactivation treatment step and organic substances that cannot be decomposed in the decomposition removal treatment step to adsorb powder or block filter media. It features a method for improving contaminated soil area by adsorption and removal by action and ion exchange action.

  Further, the filter medium is characterized by a method for improving a contaminated soil area using a mottled granodiorite ore having an action such as an adsorption action, an ion exchange action and a mineral elution.

  In the above post-treatment process, the soil is naturally dried in a curing pit and backfilled to a predetermined area, and in the case of clarified water, it is returned to the groundwater area containing biobacteria and minerals or drained separately. Characterized by soil area improvement methods.

  Further, in the above post-treatment process, the soil determined as non-contaminated soil by the inspection device is naturally dried and then backfilled to the original position, and the contaminants are passed through the inactivation treatment process, the decomposition removal treatment process, and the adsorption removal treatment process. The removed soil is characterized by a method for improving the contaminated soil area after it is naturally dried and then backfilled in a specific area surrounded by a shielding wall.

  The specific area is characterized by a method for improving a contaminated soil area in which a water shielding sheet is laid on the entire area surrounded by a shielding wall, and the dry soil from which contaminants have been removed is refilled on the water shielding sheet.

  According to the present invention, it is possible to perform inactivation treatment, adsorption removal with a specific ore, and decomposition removal with a biofungus at the same time for pollutants contained in contaminated soil and contaminated groundwater, and perform total soil replacement. Without any problem, it was possible to comprehensively improve contaminated soil and contaminated groundwater to the extent that the Contaminated Soil Control Law was cleared.

  That is, the present invention provides a pretreatment process for muddying contaminated soil to remove gravel and other non-treated substances, and deactivation by fixing the heavy metals with a silica component film in the process of agglomeration of the contaminated soil. Treatment process, Decomposition and removal process that decomposes organic substances using bio-bacteria, and Adsorption and removal process that adsorbs other heavy metals that have not been inactivated and materials that cannot be decomposed through a filtration tank The soil from which the pollutants have been removed is dried and backfilled, and the treated water from which the pollutants have been removed by the above-mentioned processes or the groundwater from which the pollutants have been removed by the decomposition removal treatment process and the adsorption removal treatment process should be used. Since it consists of a post-treatment process that returns to groundwater as clarified water or drains it separately, inactivation of pollutants, adsorption removal by specific ores, and decomposition removal by bio-bacteria proceed simultaneously Recycling on-site construction method made it possible to be constructed that.

  In addition, by returning the activated water to the contaminated area as described above, biobacteria are introduced, aerobic bacteria and microorganisms in the raw soil are activated, and purification and decomposition can be promoted. At this time, by improving the pollutant into a particle structure by an inactivation treatment process, aerobic microorganisms that feed on organic matter and are performing nitrification decomposition activities can create a “gas phase” that does not suffocate themselves. Furthermore, since the groundwater improved as described above is activated by increasing the amount of dissolved oxygen DO and mineral components, it also leads to the activation of microorganisms etc. when discharged to the outside, promoting the natural purification action Will be.

  In addition, the inactivation treatment process instantly agglomerates by acting on the soil colloid, and at the same time the alkali is neutralized with the strongly alkaline solution A in which heavy metals are encapsulated in the colloid. Because the silica component is transformed into a glass film, and it is based on a two-component type with a B-solution by a neutralization improver (pH adjuster) that makes it in an inactivated state by completely wrapping the entire soil colloid, The mud is in a stable immobilization state, and an inactivated state that hardly elutes almost permanently is obtained.

  Further, the decomposition and removal treatment step comprises a flotation decomposition tank in which a flotation separation treatment, a contact aeration treatment, and a filtration treatment are sequentially performed. The biobacteria in the filtration treatment have been improved to the aggregate particle structure by the inactivation treatment step. Since soil has air permeability, water retention and hydrophobicity, and leads to the activity of aerobic microorganisms in the soil, when groundwater is circulated gently, volatile organic compounds (VOC) and It was possible to decompose organic chemicals such as benzene efficiently and reliably.

  In addition, the above adsorption removal treatment step adsorbs other heavy metals that have not been deactivated in the deactivation treatment step, and organic substances that cannot be decomposed in the decomposition removal treatment step, to the filter medium by a specific ore. As a result, it is possible to completely remove other heavy metals and substances that cannot be decomposed.

  In addition, the specific ore used is a porphyry granodiorite ore that elutes adsorption, ion exchange, and minerals, so that harmful heavy metals such as mercury, copper, lead, and cadmium can be efficiently removed at low cost. It promotes the activation of groundwater returned to groundwater as clarified water or separately discharged water, enabling a natural purification action.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  The method for improving a contaminated soil area according to the present invention comprises adding water to a contaminated soil or a suspected contaminated soil or washing it with a washing / classifying plant to concentrate and reduce the volume of the soil to make it muddy, In the pretreatment process for removing wood, garbage, other untreated substances, and in the case of contaminated soil, heavy metals are fixed in a foreskin shape with a silica component (glass) film in the process of aggregate formation, and the amount of soil elution Deactivation treatment process with two-component type that conforms to below standard, decomposition and removal treatment process to decompose organic substances such as volatile organic compounds (VOC) and benzene using bio-bacteria, and deactivation Other heavy metals that have not been removed and organic substances that could not be decomposed in the decomposition and removal treatment process are adsorbed by passing through a filtration device, and are naturally dried in a curing pit and buried in a predetermined area. Each of the soil to be returned and the treated water from which the contaminants have been removed by the above steps or the groundwater from which the contaminants have been removed by the decomposition and removal treatment steps and the adsorption removal treatment step are returned to the groundwater area as clarified water. This is a circulation type on-site method consisting of processing steps.

  As shown in Fig. 10, specific substances that can be removed include heavy metals such as mercury (the place of utilization is microorganisms in the atmosphere) and hexavalent chromium (the place of utilization is microorganisms during wastewater treatment), PCB (the place of use is Microorganisms in soil and wastewater treatment) ・ Trichlorethylene (Used place in microorganisms in soil and wastewater treatment) ・ Tetrachlorethylene (Used place in microorganisms in soil and wastewater treatment) ・ Pesticides (Used place in microorganisms in soil)・ Hazardous chemical substances such as dioxin (use place is microorganism in soil), environmental hormone (use place is microorganism in soil), BOD ・ COD (use place is microorganism during wastewater treatment), nitrogen (use place is in soil) There are organic pollutants such as microorganisms in water and wastewater treatment), phosphorus (microbe used in wastewater treatment), oil (microbe used in soil, water and wastewater treatment)

  As shown in FIG. 1, the pretreatment process and the inactivation treatment process include a sorter 32 for washing the soil excavated and removed using the heavy machinery 31 to make it mud, and washing it. The mud after being sorted and washed by the sorter 32 is transferred to the mixer 35 by the mud pump 34 under the control of the operation management room 33. In this pretreatment process, water is added to the soil or washed by a washing / classifying plant to make the soil hydrated and muddy in a concentrated and reduced volume, and at the same time, gravel, wood, garbage and other untreated substances are removed. Will be removed.

  In the contaminated soil, the process proceeds to the next step. The mixer 35 is provided with an A liquid tank 36 into which a strong alkaline A liquid is introduced from above. When this A liquid acts on a soil colloid, it aggregates instantaneously and at the same time, heavy metals are included in the colloid.

  Further, the mixer 35 is provided with a B liquid tank 37 into which the B liquid which is a neutralization improver (pH adjuster) is charged from above. By naturally drying for about 40 days, the alkali component is neutralized, and at the same time, the silica component is transformed into a glass film and completely envelops the entire soil colloid. That is, the mud is stably fixed and is in an inactivated state that does not elute almost permanently. The dried and inactivated mud will be backfilled in situ.

  Inactivation process by the above two-component type, phosphonic acid and magnesium sulfate are mixed in a solvent that does not contain chlorine, stirred for several minutes, then administered with aluminum sulfate and polyferric sulfate, and further stirred for several minutes. An inorganic electrolytic flocculant formed can be used.

  Specifically, this inorganic electrolytic flocculant is prepared by adding 5 to 10 g of phosphonic acid and 15 to 30 g of magnesium sulfate to 50 to 100 g of the solvent, and mixing lightly for 2 to 3 minutes. After stirring, 350 g to 700 g of aluminum sulfate and ferric polysulfate are added and lightly stirred for about 5 to 10 minutes.

  Then, the mud is modified by administering an inorganic electrolytic flocculant to the mud and simultaneously administering an aqueous solution mixed with sodium silicate as a soil particle reinforcing agent and calcium carbonate as a pH adjuster. The polluted water generated at this time is clarified sequentially.

  Alternatively, the mud is stocked in a natural sedimentation tank, left standing in the natural sedimentation tank for about 2 to 3 hours, and then the floating water is clarified and discharged, and then the inorganic electrolytic flocculant is administered into the bottom mud, and further the soil particles The mud may be modified by administering an aqueous solution mixed with sodium silicate as a reinforcing agent and calcium carbonate as a pH adjuster.

  The inorganic electrolytic flocculant, the soil particle reinforcing agent and the pH adjuster synthesize inorganic metal positively charged substances having different ionic valences using a special device in a single solvent solution, and a reaction that cannot be achieved by a single positive charge. Due to its synergistic effect, it is a strong ion-binding soil improver modified to a high positive charge.

  In this soil conditioner, an ion increase phenomenon peculiar to inorganic systems occurs during the hydration reaction, and several systems of positively charged substances cause simultaneous reactions in the bottom mud. Cause strong collisional coupling and destroy the shell of the electric double layer of polluted particles and bottom mud. In other words, neutralization occurs, and electrolytic coupling based on Van der Waals's law occurs and grows into aggregate particles.

  Since the grown aggregate particles have lost their hydrophilic groups, the constrained water molecules change to free water and are pushed out of the grains by the electrolytic compression force of the particle bond (hydrophobization phenomenon), and are firmly bonded over time, and are sparse. It becomes aggregate particles (irreversible). Therefore, the treated soil never contains re-mud and includes various nutrient salts in the activated group particles to be constructed, and retains them without elution with the silica coating and hydroxyapatite.

  As an inactivation treatment process using another two-component type, an immediate-acting solidifying agent comprising an electrolytic aggregation binder and a treatment agent mixed therewith can be used. This electrolytic cohesive binder is composed of a mixture of pure water, ammonium persulfate, calcium nitrate, phosphonic acid and dilute sulfuric acid at a predetermined weight ratio, and the treatment agent is made of highly polymerized sodium polyacrylate, diatomaceous earth, or fly ash. The treatment agent is mixed with the electrolytic aggregation binder at a predetermined weight ratio to form a solidifying agent, and the solidifying agent is mixed with sodium silicate.

  Highly polymerized sodium polyacrylate as a treating agent has an amazing water absorption ability, which promotes solidification of sludge. This is because highly polymerized sodium polyacrylate has low hydrophobicity. Diatomaceous earth and fly ash are used to compensate. Diatomaceous earth and fly ash improve breathability, hydrophobicity, water retention and dispersibility. Therefore, by using these three kinds of treatment agents, sludge can be instantly solidified, and aggregated particles having air permeability, water retention and hydrophobicity can be formed.

  In addition, the use of the above electrolytic agglomeration binder makes the reduced soil an oxidized soil, which increases the amount of silica components and can be modified into healthy soils, and by using sodium silicate, improvement of silica-free in mud components. And soil hardening are further promoted, and in addition, PH adjustment is freely performed by using slaked lime.

  In the decomposition and removal treatment process, the soil improved to the aggregate particle structure by the inactivation treatment process has air permeability, water retention and hydrophobicity, which leads to the activity of aerobic microorganisms in the soil. When it is circulated, bio-bacteria are introduced into it to decompose organic chemicals such as volatile organic compounds (VOC) and benzene.

  That is, as shown in FIGS. 2 (a), (b), (c) and FIG. 3, the groundwater inside the management well surrounded by the shielding wall A is pumped up by the pump 2 through the filter 3. The flow rate control device 4 controls the flow rate so as to be sent into the relay tank 1. In the relay tank 1, an adsorbing action, an ion exchange action, and a filter medium 5 for eluting minerals are placed and installed.

  The relay tank 1 is connected to a levitation decomposition tank 11 through a measurement / analysis tank 1 ′ as necessary, and a biofringe 14 is provided in the levitation decomposition tank 11. Above the levitation decomposition tank 11, a pump 12 with an air filter and a hormic tube 13 (a tube made of porphyry granodiorite ore, preferably a tube made of granite) are arranged, and through these, a fine is formed at the bottom of the tank. A bubble generating device 15 is provided.

  The upper part of the levitation decomposition tank 11 is connected to a filtration tank 21, and a filter medium 22 for eluting adsorption, ion exchange and minerals is introduced into the filtration tank 21, and an upper intake port is provided at the bottom of the tank. An agitated submersible pump 23 is provided.

  The filter medium 5 disposed in the relay tank 1 and the filter medium 22 disposed in the filter tank 21 efficiently remove harmful heavy metals such as mercury, copper, lead, and cadmium by an adsorption action and an ion exchange action. The powdered or block-like porphyry granodiorite ore is used, but what is called Ohiroishi (trade name) is used as the optimum ore.

  Since the ore is superporous, it has a very large surface area, and its main components are silicic anhydride and aluminum oxide, and therefore has excellent adsorption and ion exchange effects. Even in the adsorption test of E. coli, the removal rate is always high.

  In addition, a part of the filtration tank 21 is connected to a discharge port or a water intake for inspection through a branch pipe 24, and the other part is a groundwater area through a water pipe 25 having high water permeability and durability. The water is refluxed to the aquifer. FIG. 2 (c) shows a schematic cross-sectional view of the raised area showing the circulation of groundwater.

  The filter media 5 and 22 and the hormic tube 13 that elute adsorption and ion exchange and minerals use the ore of the mottled granodiorite with the scientific name, and the components of the ore are mainly composed of anhydrous silicic acid and aluminum oxide. In addition, it is a super multi-component ore containing minerals necessary for the human body such as iron, calcium, manganese, magnesium, silicon, sodium, phosphorus, and titanium. The filter media 5 and 22 and the hormic tube 13 are ores that efficiently remove harmful heavy metals such as mercury, copper, lead, and cadmium by a synergistic effect of the adsorption action and the ion exchange action. There is Ohiroishi (trade name) as the most suitable one.

  As shown in FIG. 7, the biodegradable sludge degradation mechanism is difficult for general activated sludge fungi because the cell membrane is made of phospholipid and is hydrophobic. By creating a lipolytic enzyme, it can break down cell membranes into glycerin and fatty acids. Another digestive enzyme breaks down each of these, and eventually converts them into water and carbon dioxide.

  As shown in FIG. 8, the amino acids produced by the biobacterium include glycine, alanine, valine, leucine, isoleucine, serine, proline, threonine, aspartic acid, asparagine, glutamic acid, glutamine, histidine, lysine, cystine, algin, methionine. -Phenylalanine, tyrosine, tryptophan, etc.

  FIG. 9 shows a list of assumed digestive enzymes and their functions. The types of enzymes are divided into hydrolases, oxidoreductases, leaching enzymes, transferases, and synthases, and the functions of biofungi are clearly shown.

  Among the porphyry granodiorite ores, the adsorbing power of the filter media 5 and 22 and the hormic tube 13 made of large broad stone is 100% of lead and methylene blue and copper is 7 days later as shown in FIG. 5 (a). It was 92.2%, mercury was 79.5%, cadmium was 63.0%, fluorine was 38.0%, and hexavalent chromium was 24.2%. Further, as shown in FIG. 5B, the mineral elution amount (mg / liter) is 17.2 for potassium, 13.7 for sodium, 12.4 for calcium, 4.28 for magnesium, and 3.28 for silicon. 19, 0.14 for aluminum, 0.04 for manganese, and 0.01 for iron.

  The progress of bioremediation monitoring is indirectly measured by measuring the redox potential, pH, humidity, DO, oxygen concentration, electron acceptor / donor concentration, decomposition products (carbon dioxide, etc.) of soil and groundwater. Can be monitored. The relationship between the biological degradation rate and the redox potential is as shown in FIG. In particular, there exists a biobacteria in which a microorganism that reduces divalent mercury to metallic mercury reduces hexavalent chromium to trivalent and removes the precipitate. There are also microorganisms that decompose organochlorine compounds.

  In the above, although it demonstrated along the clarification of groundwater, the same process is performed also about the polluted water or floating water which arises by the improvement process of the above-mentioned contaminated soil.

  Next, an example of use and operation of the best mode configured as described above will be described. First, as shown in FIG. 1, in the deactivation process, the contaminated soil excavated and removed using the heavy machinery 31 or soil suspected of being contaminated soil is made into mud soil, and then put into the sorter 32, where Wash to remove large gravel, sand, wood and debris.

  The removed gravel and sand are confirmed to be safe and then backfilled at the excavation site or processed separately.

  The mud after washing is transferred to the mixer 35 by the mud pump 34 under the control of the operation management room 33. A strong alkaline A liquid in which silica is ionized is supplied from the A liquid tank 36 to the mixer 35 and sufficiently stirred and mixed. At this time, when the liquid A acts on the soil colloid, it instantly aggregates and at the same time the heavy metals are embedded in the colloid.

  And the B liquid which is a neutralization improving agent (pH adjuster) is thrown in from the B liquid tank 37, and it is naturally dried in the curing pit 38 for about 40 days after mixing, whereby the alkali is neutralized and at the same time the silica component is It transforms into a glass film and completely envelops the entire soil colloid. Accordingly, the mud is stably fixed, and is hardly semi-permanently eluted, so that it is in an inactivated state in which mud formation is suppressed again.

  2 (a), (b), (c) and FIG. 3, groundwater in a specific area surrounded by the shielding wall A is pumped up to the relay tank 1 by the pumping pump 2, and the patchy granite Sediment is precipitated and separated through a filter medium 5 made of diorite ore.

  The water to be treated after the precipitation separation is sent to the adjacent levitation decomposition tank 11 through the measurement and analysis tank 1 ′ as necessary, where it is aerated through the biofringe 14 by the operation of the microbubble generator 15.

  After the aeration treatment, it is sent to the adjacent filtration tank 21, and harmful heavy metals such as mercury, copper, lead and cadmium contained in the water to be treated are efficiently removed by the adsorption action and ion exchange action of the filter medium 5. Is done.

  Then, the treated water that has been clarified by adsorption and ion exchange action in the filtration tank 21 and provided with minerals is partially connected to the outlet or the intake for inspection through the branch pipe 24, and the other part. Is returned to a groundwater zone in a specific area through a water permeable pipe 25 having high water permeability and durability.

  Thus, as shown in FIG. 4, by returning the activated water containing minerals to the contaminated area, biobacteria and aerobic bacteria and microorganisms in the raw soil are activated, thereby promoting purification and decomposition. The biggest feature at this time is that the pollutants are improved to a aggregate structure by an inactivation treatment process, and aerobic microorganisms that feed on organic matter and perform nitrification decomposition have a “gas phase” that they do not suffocate themselves. I'm making it.

  Moreover, since the groundwater improved as described above is activated by increasing the amount of dissolved oxygen DO and mineral components, it also leads to the activity of microorganisms and the like when discharged to the outside, and the natural purification action is promoted. Therefore, it is possible to suppress the occurrence of red tides, for example.

  In the above description, groundwater has been described. However, contaminated water and floating water generated by the process of improving contaminated soil can be clarified water by the same treatment as described above.

  The result proof by the public institution which tested the soil improvement combining the above-mentioned inactivation processing process and decomposition removal processing process is shown below.

  The analysis result of the contaminated sample X (the measurement certificate of Heisei Riken Co., Ltd.) whose collection location is benzene-containing soil-dissolved water has a benzene concentration of 1590 mg / L (measurement method JIS-K0125-5).

  Moreover, the analysis result of the sample Y whose biocidal site is biobacteria-decomposed treatment water (the measurement certificate of Heisei Riken Co., Ltd.) has an extreme benzene concentration of 0.01 mg / L or less (measurement method JIS-K0125-5). Diminished.

  In the sewage, about 13300,000 / g of biobacteria exist as general bacteria (according to sanitary test method 1.3.1.2. (4) (24-hour plate culture method)).

  For example, the total mercury contained in the contaminated soil is 0.08mg / liter, arsenic 8mg / liter, selenium 0.7mg / liter, fluorine compound 39.5mg / liter, boron 11mg / liter, lead 14mg / liter By the chemical treatment step P, total mercury 0.0005 mg / liter or less, arsenic 0.001 mg / liter or less, selenium 0.001 mg / liter or less, fluorine compound 0.2 mg / liter or less, boron 0.1 mg / liter or less, lead 0 0.005 mg / liter or less.

  In addition, the total mercury contained in the contaminated soil is 0.0067 mg / liter, arsenic 0.32 mg / liter, selenium 0.04 mg / liter, benzene 0.01 mg / liter, lead 2.83 mg / liter is decomposed and removed. As a result, total mercury was 0.005 mg / liter or less, arsenic 0.001 mg / liter or less, selenium 0.001 mg / liter or less, benzene 0.01 mg / liter or less, and lead 0.01 mg / liter or less.

  In a contaminated area certified as a contaminated soil area, the contamination rarely extends to the entire contaminated soil area, and is often limited to a specific area. This is often limited to locations where the pollutants have been handled or discharged in the past of the area, or in the vicinity thereof. Therefore, the process of inspecting whether the soil is contaminated in advance at the location is necessary. At that time, if the soil does not fall under the contaminated soil but the test result approximated to it is transferred to the next step, the other soil is maintained as it is.

  FIG. 11A shows a distinction between a contaminated portion or a portion similar to the contaminated portion (hereinafter referred to as a contaminated section 41) and a non-contaminated section 42 that was not the result of the inspection. For example, the contamination section 41 is specified by examining every 30 m × 30 m.

  When it is recognized as the contaminated section 41, the same process as in the first embodiment is performed, but the contaminated section 41 also includes soil that is not so. Therefore, as shown in FIG. 12, in the pretreatment step, water is added to the contaminated soil or washed with a washing / classifying plant to make the soil hydrated and mudified in a state of concentration and volume reduction, resulting in gravel, wood, and garbage. In addition, other non-treated substances are removed, and at the same time, the contamination degree of the soil is inspected by the inspection device 43, and is classified into the contaminated soil and the non-contaminated soil by the classifying device 44. It transfers to an inactivation process, and in non-contaminated soil, it transfers to the curing pit 38 '.

  Non-contaminated soil will be backfilled in its original area after natural drying, but soil that has been inactivated as contaminated soil will be backfilled in natural containment area 45 after natural drying. Become.

  As shown in FIG. 11 (b), the inactivated soil is filled as a planting base as shown in FIG. 13 (b), for example, among all the areas where improvement of the contaminated soil area is required. It will be backfilled to a specified containment area 45 such as a road or parking area that has been surface-finished with a forest area or asphalt.

  As shown to Fig.13 (a), the containment area 45 surrounds the said area with shielding wall A ', spreads the water-impervious sheet | seat 46, and backfills the soil inactivated in the upper space. .

  By identifying the contaminated soil and treating only the identified contaminated soil, the amount of soil subject to inactivation treatment can be reduced, and by containing them in a specific area, the contaminated soil area It is possible to further enhance the safety of the system. Furthermore, the containment area 45 is a small area as compared with the entire improvement area, and the installation area of the shielding wall A ′ surrounding the area and the laying area of the water shielding sheet 46 can be reduced. It becomes an improvement means.

The construction using the shielding wall A ′ and the water shielding sheet 46 is based on vertical water shielding work as shown in FIGS. 14 (a), 14 (b), and 14 (c).
The vertical water-impervious work is assumed to be a three-layer shielding wall A ′ in which a water-shielding layer made of a high-density polyethylene sheet is inserted into a soil cement wall body.
Since the constructed shielding wall A ′ has a three-layer structure in which the soil cement wall itself is hardly water permeable and further inserted with geolock, it is possible to exhibit a highly reliable water shielding performance. Geolock is to build a continuous shielding wall A 'by using a high-density polyethylene sheet with excellent chemical resistance and durability, and a water-swelling water-stopping material (sealing material) at the joint. Is possible.
As the soil cement wall construction method, TRD or excavation replacement can be selected, so it can cope with any soil quality on land. The possible construction depth is approximately 20m, and the construction is done to reach the hardly permeable layer.
The surface impermeable work is made of a high-density polyethylene sheet (HDPE sheet), and the upper and lower sides of the sheet are protected by protective mats. It has excellent durability such as mechanical strength, weather resistance, chemical resistance, and heat resistance, and is excellent in followability to ground deformation due to its flexible material. Also, by using the same material as the shielding wall and the shielding sheet laid on the excavation surface, it is possible to weld directly to the shielding wall, and as an integrated structure that integrates the surface impermeable work and the vertical impermeable work It becomes possible to contain inactivated soil.

  Contaminated water such as ground water, polluted water or floating water is treated in the same manner as in the first embodiment.

  A specific configuration including various devices in each step of the pretreatment process, the inactivation treatment process, the decomposition removal treatment process, the adsorption removal treatment process, and the post-treatment process according to the present invention is limited to the above-described embodiment. However, the present invention includes modifications and improvements as long as the object of the present invention can be achieved.

It is explanatory drawing which shows an example of the inactivation process process in the best form for implementing this invention. (A) It is explanatory drawing in the top view which similarly shows an example of a decomposition removal processing process and an adsorption | suction removal processing process, (b) It is explanatory drawing in sectional drawing. It is explanatory drawing in the schematic sectional drawing of a soil and a groundwater area similarly. It is explanatory drawing which similarly shows the flow of a process of a decomposition | disassembly removal process process and an adsorption | suction removal process process. It is explanatory drawing explaining the operation | movement which accelerates | stimulates a purification | stimulation and decomposition | disassembly by activating biobacteria and aerobic bacteria and microorganisms in raw soil by returning activated clarified water to a contaminated area. It shows an example of a filter medium using Oohiroishi, (a) is a diagram showing the adsorption power of Oohiroishi, (b) is a table showing the amount of mineral elution of Oohiroishi in tabular form. It is the figure which showed the relationship between the biological degradation rate and oxidation-reduction potential in monitoring of bioremediation. It is explanatory drawing which shows the degradation mechanism by a biomicrobe. It is the figure which showed an example of the amino acids which a biomicrobe produces. It is a figure which shows the list of digestive enzyme and its function. It is the figure which showed the pollution target substance and the utilization place in the table | surface. (A) The top view which showed the area of the contaminated soil and the non-contaminated soil, (b) It is the top view which backfilled the specific area by inactivating the contaminated soil. It is explanatory drawing which shows an example of the inactivation processing process of the other Example in the best form for implementing this invention. (A), (b) It is a schematic sectional drawing of the state which backfilled inactivated soil to the specific area. (A) Cross-sectional view of vertical water-impervious construction using shielding wall, (b) Cross-sectional view of connecting portion of water-impervious sheet, (c) Cross-sectional view of shielding wall.

Explanation of symbols

A, A 'Shielding wall 1 Relay tank 1' Weighing analysis tank 2 Pumping pump 3 Filter 4 Flow rate control device 5, 22 Filter medium 11 Floating decomposition tank 12 Pump 13 with air filter 13 Holmic tube 14 Bio-off lineage 15 Fine bubble generator 21 Filtration tank 23 Stirring submersible pump 24 Branch pipe 25 Permeable pipe 31 Heavy machine 32 Sorting machine 33 Operation control room 34 Mud pump 35 Mixer 36 A liquid tank 37 B liquid tanks 38 and 38 'Curing pit 41 Contaminated section 42 Uncontaminated section 43 Inspection device 44 Classification device 45 Containment area 46 Water shielding sheet

Claims (10)

  A pretreatment process to muddy the soil and remove gravel and other untreated substances, and an inactivation process to fix heavy metals with a silica component film in the process of agglomeration in contaminated soil Decomposition and removal treatment process that decomposes organic substances using bio-bacteria, Adsorption and removal treatment process that adsorbs other heavy metals that have not been inactivated and materials that cannot be decomposed through filtration tanks, and contamination The soil from which the substances are removed is dried and backfilled, and the treated water from which the contaminants have been removed by the above-mentioned processes or the ground water from which the contaminants have been removed by the decomposition and removal treatment process and the adsorption removal treatment process are clarified water. A method for improving a contaminated soil area, characterized by comprising a post-treatment step of returning to a groundwater area or draining separately.   The pre-treatment process is performed by adding water to the soil or washing it with a washing / classifying plant to make the soil hydrated and muddy in a concentrated and reduced volume, thereby removing gravel, wood, debris and other untreated substances. The method for improving a contaminated soil area according to claim 1.   In the pretreatment process, water is added to the soil or washed with a washing / classifying plant to make the soil hydrolyzed and muddy in a concentrated and reduced volume, removing gravel, wood, garbage and other non-treated substances. At the same time, the soil analyzed by the inspection device is classified as non-contaminated soil, the post-processing step is backfilled, and the soil is classified as inactivated processing step. 2. The method for improving a contaminated soil area according to claim 1.   The deactivation treatment step is to instantly agglomerate by acting on the soil colloid, and at the same time the heavy metal is contained in the colloid, the strongly alkaline A solution, and at the same time the alkali is neutralized, the silica component is It is a two-component type with a B solution by a neutralization improver (pH adjuster) that transforms into a glass film and completely encases the entire soil colloid so as to be inactivated over a long period of time. Item 4. The method for improving a contaminated soil area according to any one of Items 1 to 3.   5. The decomposition and removal treatment step is performed by sequentially performing a flotation separation treatment, a contact aeration treatment, and a filtration treatment, and decomposes and removes the organic substance by the biobacteria in the filtration treatment. Contaminated soil area improvement method as described.   In the adsorption removal process, other heavy metals that were not inactivated in the deactivation process and organic substances that could not be decomposed in the decomposition process, the adsorption action and ions of the filter material in the form of powder or block The method for improving a contaminated soil area according to any one of claims 1 to 5, wherein adsorption removal is performed by an exchange action.   7. The method for improving a contaminated soil area according to claim 6, wherein the filter medium uses a mottled granodiorite ore having an action such as an adsorption action, an ion exchange action and a mineral elution.   The post-treatment process is characterized in that the soil is naturally dried in a curing pit and backfilled into a predetermined area, and the clarified water is returned to the groundwater area containing biobacteria and minerals or drained separately. The method for improving a contaminated soil area according to any one of claims 1 to 7.   In the post-treatment process, the soil determined as non-contaminated soil by the inspection device was naturally dried and then backfilled in situ, and the contaminants were removed through the inactivation treatment process, the decomposition removal treatment process, and the adsorption removal treatment process. The method for improving a contaminated soil area according to any one of claims 3 to 7, wherein the soil is back-filled in a specific area surrounded by a shielding wall after natural drying.   10. The contaminated soil area according to claim 9, wherein the specific area is constructed by laying a water shielding sheet over the entire area surrounded by the shielding wall, and refilling the dry soil from which the pollutants have been removed on the water shielding sheet. How to improve.

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