FI119501B - Procedure to clean contaminated soil - Google Patents

Abstract

The invention relates to a method for cleaning polluted soil, in which method, mycelial filaments are used in cleaning the polluted soil which filaments are added in substrate suitable for mycelial filaments and transferred to the soil to be cleaned. The method according to the invention is characterised in that the substrate containing mycelial filaments is dosed inside a filament tube (3; 9; 10), after which the filament tubes (3; 9; 10) are closed with an air-tight protective film and in the soil (1) to be cleaned are formed at least one planting hole (2) and at least one aeration hole (4) at a suitable distance from it. After this, the protective film is removed from around the filament tube (3; 9; 10) and the filament tube is fitted in the planting hole (2) made in the soil (1), after which an air feed channel (5) of an air feed device is installed in the aeration hole (4) and air is conveyed by the air feed device in the soil, whereby mycelial filaments start to grow from the planting hole (2) towards the aeration hole (4) simultaneously cleaning impurities in the soil (1) and rotting organic matter in the soil.

Description

119501

METHOD FOR CLEANING contaminated soil

The invention relates to a process for the purification of contaminated soil, which method comprises the purification of contaminated soil, which is added to a suitable growth medium for the fungal mycelium and transferred to the soil to be purified.

Polychlorinated dibenzo-p-dioxins and dibenzofurans (collectively dioxins or PCDD / F) are toxic organic chlorine compounds found almost everywhere in the environment, mainly from industrial and transport emissions due to chlorination and incomplete combustion. The most important dioxin suburbs in Finland are the antifouling agents used in sawmills, where the active ingredient has been chlorophenols and dioxins are present as impurities. Very high levels of dioxins have been found in several sawmills.

When fat-soluble, dioxins bind strongly to soil organic matter. Thus, high dioxin concentrations occur mainly in the soil surface. The migration of these pollutants into surface water and groundwater is negligible at many sites. However, even at low concentrations, dioxins are highly toxic (long-term exposure at levels of 20 ng / kg may cause health hazards). They are developmental and reproductive toxic and may affect metabolism, enzyme production, hormone function and cause neurological and im-20 alterations in the immune system. Thus, the surface of the sawmills is transported with dust. or exposure to dioxins through direct contact may pose a risk to health and the environment.

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The harmfulness of dioxins is partly based on their persistence and non-degradability. This feature also complicates the development of remediation methods for: ***: 25 dioxins. The most commonly used dioxin remediation • · · method today is excavation and transport to a landfill site for contaminated land, where the masses are landfilled. Some of the dioxin-contaminated pulps can be disposed of in landfill for non-hazardous waste. These masses are often • ·

'1' are slightly contaminated and comply with EU Council Decision 2003/33 / EC

··· 30 December 19, 2002 Landfill of non-hazardous waste.

*: ** · Alternatively, the masses may be disposed of in a hazardous waste disposal site.

However, currently the only practicable and environmentally friendly treatment method for pulps that are heavily contaminated with dioxins is thermal treatment. This method also supports international guidelines and actions and national regulations to control and control environmental problems caused by persistent organic pollutants (POPs). (See Aug. 22, 2002/735) According to a government decree, persistent organic compounds must be decomposed or removed rather than landfilled, Combustion 5 can be considered as BAT for the treatment of dioxin-contaminated land.

Sawmills are Finland's largest source of dioxins. The soil in the sawmill areas is often rich in wood and thus in organic matter. At present, the only recommended and environmentally friendly treatment method for pulps contaminated with dioxins is incineration. The treatment capacity of the incinerator decreases in direct proportion as the amount of organic matter increases. When the organic material burns, the gas purification system in the combustion plant becomes clogged. Thus, the amount of material to be burned must be reduced in order to maintain the performance of the equipment when handling high organic masses. This significantly increases the cost of treating pi-15 decayed soil with the incineration process and prevents the spread of the best available method as a treatment method for pulps containing POPs.

It is an object of the invention to provide a method for removing the above-mentioned problems associated with the present contaminated soil purification methods. In particular, it is an object of the invention to provide a method for purifying contaminated soil without incinerating the contaminated soil.

. ···. It is a further object of the invention to provide a low-cost method for cleaning, e.g., dioxin-contaminated soil without soil.

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'* // removal of soil from the soil, and which can treat heavily contaminated soils so that the incineration of such soils is simpler and less costly.

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The object of the invention is achieved by a process for the purification of contaminated soil, which is characterized by what is claimed.

The method according to the invention is characterized in that: · *: 30 medium containing mycelium is administered into the mycelial tube of ···. ***. afterwards, the mycelial tubes are sealed with an airtight protective film, ··· .. · at least one planting hole is formed on the soil to be cleaned and at least one aeration hole is removed at a suitable distance, · · · * · * · the protective film is removed The 35 material planting holes, 3 119501, are installed in the aeration hole air supply unit air supply channel, - air is supplied to the soil by the air supply unit, whereby the fungal mycelium begins to grow from the planting hole to the aeration hole while cleaning the soil for organic matter and debris.

Such a method provides a much simpler and more cost-effective method of purifying contaminated soil which is currently known, since such a method does not necessarily have to be transferred to a different site for treatment 10, but can be carried out on site by immersing air supply pipes to contaminated soil. The method is also very simple to implement in practice, since it is sufficient to drill a sufficient number of holes of sufficient depth into the ground so that the strap and air supply pipes are installed. Further, growing the fungal mycelium into mycelial tubes and pumping air into the soil / heap soil are simple and low cost measures in relation to the operation and operating costs of the waste incineration plant. In addition, such a process can be used to treat very heavily contaminated soil / soil as a pretreatment to reduce soil contaminants such as dioxins to such an extent that incineration can be carried out at mass incineration plants much simpler and less expensive than current incineration processes.

··: '·· In one embodiment of the method of the invention, the substrate used is * * m m ,,. Ϊ substrate of refined straw and bark, and as mycelium tube: torn stainless steel tube. In such a growth medium, the fungal mycelium is made to grow as quickly and uniformly as possible.

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The advantage of the stainless steel belt tube is the good height ···. resistance to corrosion and mechanical stress (including ground pressure). In addition, stainless steel strap tubes can be recycled because they are durable and can be easily cleaned of used sponge straps and vegetable substrates.

· * ·. ] ·. In one embodiment of the method of the invention, a protective film is used to form a protective film of air and vapor sealed around the mycelial tube. With such a protective film, the mycelium tube is • • * ·· easily and preferably sealed inside a sealed package that prevents moisture evaporation. In this way, the medium inside the 35 protected mycelial tubes can easily maintain 4,119,501 suitable moisture to provide the most favorable growth conditions during the mycelial growth phase.

In one embodiment of the method of the invention, several aeration holes are made around a single implantation hole. When a Rih-5 mast tube is installed in such a planting hole, and the venting tubes, the air supply tubes begin to grow from the mycelial tube in the direction of all the aeration tubes. Thus, with such an arrangement, the mycelium of a single mycelium tube is spread as wide as possible. This is of course advantageous when, for example, there is a large amount of soil to be cleaned and / or a large surface area.

In one embodiment of the method according to the invention, a soil is formed into the soil with a depth of about 50 to 80 cm. Typically, fungal species suitable for soil remediation are living close to the soil surface. As a result, such a planting hole depth is very suitable for many fungal species. In addition, dioxin, for example, is most often accumulated in organic soils near the soil surface. Thus, most of the impurities in the pulp can be cleaned by a tube immersed to a depth of 50-80 cm. Further, making deeper holes will slow down planting holes and increase costs because more efficient and expensive equipment is needed to make the holes.

In one embodiment of the method according to the invention, a plurality of essentially horizontal planting holes are formed at the top of the plant, and aeration holes are made underneath the planting holes when the soil is stacked. In this way, mushrooms • · / ·; ' the mycelium can also be effectively grown from the top down. In addition, such a · · ·: j: arrangement is practically easy to carry out when decontaminating soil.

• ♦ • · ♦. ···. In one embodiment of the method of the invention, the planting holes are made into a plurality of overlapping rows and / or layers. With such an arrangement it is possible to ... clean up the soil deposited in the ditch very efficiently, when there is a large amount of soil to be cleaned in relation to the area used for cleaning, since it can be carried out in small but relatively in high spirits.

··· «·· • m •» 1

In one embodiment of the method according to the invention, the contaminated soil ··: * · * is cleaned by drilling planting holes and aeration holes at a distance of about 50 cm. In this way, the mycelial mycelium is spread as much as possible over the soil, whereby the area can be treated evenly and comprehensively throughout.

In the following, the invention will be explained in more detail with reference to the accompanying drawings, in which Figure 5 shows a cross-section of contaminated soil formed with planting holes in which planting tubes and air supply tubes containing fungal mycelium grown in a substrate are mounted.

Figure 2 is a plan view of the planting and air supply pipes of Figure 1, Figure 3a is a view of the air supply and planting pipes in another embodiment of the method of the invention, Figure 3b is the positioning of air supply and planting tubes in a third embodiment of the method 3c shows an arrangement of air supply and planting pipes in a fourth embodiment of the method according to the invention.

In a method according to the invention, dioxin-contaminated soil 1 is purified. To this end, a purified medium is prepared from purified straw and bark by the addition of a fungus belonging to a group of fungi suitable for purification. Fungi belonging to this group of fungi have a nonspecific peroxidase enzyme-based pathway for the degradation of complex and intractable compounds. As a result, they are able to degrade many difficult to decompose compounds such as chlorophenols and polyaromatic hydrocarbons. Subsequently, the medium containing such fungal mycelium is metered into the mycelial tubes 3. The mycelial tubes are perforated, · * ·. stainless steel tubes with an external diameter of about 100 - ··. * 25 150 mm. Next, the mycelial tubes are sealed in air- and vapor-tight plastic packages for about 2 weeks to grow mycelial tubes before applying the mycelium tubes to the soil to be cleaned 1.

: A: In order to embed the mycelial tubes into the soil, several planting holes 2 have been drilled into soil 1 of the area to be cleaned as shown in Figures 1 and 2, and aeration holes 4 of significantly smaller diameter are planted between the planting holes 2 *** \ in the case of about 0.5 m. and a depth of about 50-80 cm. After drilling the planting and aeration holes, the plastic packages of the strap tubes 3 are removed and the strap tubes are fitted into the planting holes 2. Next, the air supply tubes: 1: Air supply tubes 5 are introduced into the holes 4. n hoses, the ends of which are fitted to the vent holes 4 and whose plurality of holes are formed at the walls of the parts to be fitted inside the vent holes. The air supplied to the II manifolds is provided, for example, by means of a suitable compressed air compressor (not shown in the figures) or other suitable air supply device providing a suitable pressure of about 2 bar and sufficient air flow. Several air supply pipes are usually connected to one air supply device. The air supply pipes are so long that they can be led from the aeration holes to a pumping station located at a convenient location, which may have one or more air supply units depending on the size of the area to be cleaned and the number of air supply pipes required.

10 With the strap tubes 4 mounted in the aeration holes 3, the pumping of air is started and maintained throughout the growth phase. As the pumping starts, the fungal mycelium begins to grow gradually through the aeration holes towards the airy soil that enters the ground. As the fungal mycelium grows, it degrades the organic soil in the soil and purifies and cleaves the impurities in the soil 15. This usually takes about 2-4 weeks, depending on soil quality and weather conditions. After a suitable growth phase, the mycelium tubes are removed from the planting holes, whereupon the mycelium remaining in the soil continues to decompose organic soil and clean up the soil. Soil contamination can be monitored by sampling the soil. In the case of mild to 20 moderately contaminated sites, the process generally results in sufficient site remediation without the need for post-treatment. When heavily contaminated areas are cleaned, the soil of the area can be post-treated with known butter, eg, by burning the pre-treated soil in a pulp incinerator. This reduces the amount of organic matter to be burned by reducing the amount of organic matter to be burned: *** · 25 so that the clogging of the flue gas cleaning equipment is substantially reduced. This will significantly reduce the cost of rehabilitating heavily contaminated land. In the case of slightly and moderately contaminated land, incineration is largely avoided. Thus, in such a situation, the method can save e.g. the costs of earth moving and transportation.

• · • · ···. Figures 3 ac illustrate some other applications of the inventive method • · · i "! (I. E., They deal with contaminated soil deposited in a well 6 or a top open, wall enclosed space. 7 7) Such applications of the method are well suited: * ·· e.g., incineration as a method for pretreating heavily contaminated soil, since it removes contaminated soil from the soil and puts it on top of the aeration tubes 8 (Figs. 3a and 3c) or 119501 7 in a box-shaped space 7 (Fig. 3b). 3a and 3b, or a plurality of individual belt tubes 10 are deposited on the soil above the aeration tubes 11 at even intervals in accordance with Figure 3c.

Naturally, the method according to the invention may still differ in many respects from the above embodiments. The position, order, materials, diameters of the mycelial tubes and aeration tubes, as well as the substrate raw materials may vary, e.g. depending on the type of soil to be cleaned and the harmful substances therein. Also, the fungal species used in the method may vary. In one embodiment of the method, two or more species of the same or different species of fungi may be used simultaneously, if possible.

The invention is not limited to the preferred embodiments shown, but may vary within the inventive idea of the claims.

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Claims (10)

A process for the purification of contaminated soil (1), wherein the purification of the contaminated soil (1) is carried out by adding a fungal mycelium to a suitable medium for the fungal mycelium and transferring it to the soil to be purified (1). the substrate is metered into the mycelial tube (3; 9; 10), after which the mycelial tubes (3; 9; 10) are sealed with an airtight protective film, at least one planting hole (2) is formed on the soil to be cleaned (1) and at least one aeration hole (4), - removing the protective film around the mycelial tube (3; 9; 10) and inserting the mycelial tube into the planting hole (2) made of soil (1), - installing the air supply duct (5) in the air supply device, air, whereby the fungal mycelium begins to grow from the planting hole (2) to the aeration hole (4), cleaning the same 11a, and by decomposing the organic soil in the soil. Method according to Claim 1, characterized in that the substrate for the growth 20 is a refined straw and bark substrate and that the filament tube (3; 9; 10) is made of rusted stainless steel. made tube. The method according to claim 2, characterized in that a plastic film is used as the protective film to form the mycelial tube (3; 9; 10): sealed air- and vapor-tight packaging. ·· * · • o ·· » Method according to one of Claims 1 to 3, characterized in that several aeration holes (4) are made around one of the planting holes (2). 30 *. · **. Method according to one of Claims 1 to 4, characterized in that "a soil is formed in the planting hole (2) having a depth of about 50 to 80 cm." Method according to one of Claims 1 to 5, by which the soil (1) assembled into a kernel is cleaned, characterized in that a plurality of mainly horizontal planting holes (2) are formed in the upper part of the kernel and that aeration is carried out. - the holes (4) are made below the planting holes. 9 119501 Method according to Claim 5, characterized in that the planting holes (2) are made in a plurality of overlapping rows and / or layers. Method according to one of Claims 1 to 7, in which the contaminated soil (1) is cleaned with fungal mycelium, characterized in that planting holes (2) are drilled into the ground and at a distance of about 50 cm from them are ventilation holes (4). 8 119501 Method according to Claim 8, characterized in that the holes 10 (2,4) are drilled in a substantially vertical position. Method according to Claim 8 or 9, characterized in that a plurality of planting holes (2) are drilled around one aeration hole (4). · ♦ · «· M M M M · · · • 9 9 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 · • • • · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ···