LT4559B - Process and system of the microbiological rectification of soil contaminated with oil or oil-products - Google Patents

Abstract

This invention is related to the field of environmental biotechnology, namely to microbiologic cleaning of soil pollution with oil or oil products and it may be used against environmental pollution. Soil polluted with oil or oil products is cleaned by creating favourable conditions for the activity of oxidizing micro-organisms present in the soil, namely organic materials are introduced into the polluted soil. Organic materials are mixed with the polluted soil. The draining foundation is formed on a hard waterproof site surface. On the foundation, the soil being cleaned is piled up with intermediate layers of organic materials between the soil being cleaned, where all insertion means of irrigation, aeration and biological preparations being inserted into the cleaning soil are placed.

Description

BACKGROUND OF THE INVENTION The invention relates to the field of environmental biotechnology, and more particularly to the microbiological cleaning of soil contaminated with petroleum or petroleum products and may be used for environmental protection.

It is known that oil transportation, refining, storage and use often lead to accidents, pollution of the environment and its products. In order to protect the environment from the spread of harmful pollutants, the contaminated soil is immediately mechanically collected and cleaned at designated sites.

Known method of microbiological cleaning of water, soil and surfaces contaminated with petroleum products, described in patent specification RU 2007372, where contamination of the environment at pH

3.5 - 6, processes the suspension of micromycetes Candida guillermondii-Y-241 cells and mineral additives, nitrogen and phosphorus fertilizers, using nitrogen fertilizers 15 - 2500 mg / l and phosphorus fertilizers - 10 - 1500 mg / l.

The disadvantage of this method is that it is only suitable for surface treatment of water or other surfaces contaminated with petroleum or petroleum products, and inefficient when larger amounts of contaminated soil need to be applied, since the thinned soil needs to be applied in a thin layer. aerobic conditions necessary for cleaning.

A known method of microbiological cleaning of oil-contaminated soil is described in patent specification RU 2019527, wherein the soil contaminated with oil and petroleum products is treated with an aqueous suspension of bacterial cultures Rhodococcus erythropolis E-15 and mineral nitrogen-phosphorus fertilizer. Nitrogen-phosphorus fertilizers (nitrofosk or nitroamofosk and sodium nitrate) and an aqueous suspension of bacterial preparation are added to the treated soil in the amount of 1 - 10 g / m ^{2 of} soil, 115 g / m ^{2 of} nitro and 400 g / m of sodium nitrate. ² primers. The soil is treated in the following way: 2/3 of the dry fertilizer mixture for soil treatment is added to the soil contaminated with petroleum, then it is treated with a mixture of bacterial preparation aqueous suspension and 1/3 of mineral fertilizer, then the soil is digested and left for 1.5 - 2 months. .

The disadvantage of this method is its low efficiency, as it allows the treatment of a relatively thin layer of soil and thus a small amount of contaminated soil. Larger production areas are required to handle larger amounts of soil, which is unavoidable in emergencies.

Also known is a microbiological method for treating sludge contaminated with petroleum or petroleum products and the apparatus disclosed in the specification of SU 1637328, wherein sludge contaminated with petroleum is treated by an association of microorganisms, i. y. when treating cultures of Pseudomonas aeruginosa BKUM B-2537, Bacillus sphaericus BKUM B-2558 and Bacillus licheniformis BKUMB-3779 in a 3: 2: 3 ratio using biological treatment plant sludge in combination with oxygen-containing organic compounds when oil-contaminated sludge and the proportion of organic nutrient compounds is (1000-2000): 1. The above process is carried out at 55-60 ° C. The unit implementing the method comprises a bioreactor, a unit working capacity, means for supplying sludge and removing the treated sludge from the unit. For treatment of contaminated sludge, perforated baffles, inclined at an angle, are placed on opposite sides of the inner wall of the working capacity of the unit, to divide the treated sludge and interact with the microorganism association. In the center of the unit, a gap is left between the baffles for the downflow of treated sludge.

The disadvantage of this method is its low efficiency in cleaning up large amounts of contaminated soil, as the described device cleans up a small amount of oil contaminated soil in a single process due to its low working capacity, complicated microorganism insertion, complex aeration system, high temperature and constant device maintenance.

SUMMARY OF THE INVENTION The object of the present invention is to increase the cleaning efficiency by cleaning a large amount of soil contaminated with petroleum or petroleum products, utilizing the microorganisms present in the soil and facilitating their vital activity and biological activity. Furthermore, the invention aims at simplifying the means of realizing the method and reducing the cost of the purification process.

The present invention solves the problem of treating soil contaminated with petroleum or petroleum products with oil-oxidizing microorganisms, providing optimum conditions for their vital and biological activity, namely, adding organic matter to the contaminated soil, mixing the contaminated soil with organic matter, and forming an impermeable The substrate is stacked with layers of organic matter in layers, which contain means for wetting, aeration and incorporating biogenome preparations into the substrate.

Organic matter with high cellulose content is added to the contaminated soil. These are inexpensive locally sourced materials, namely straw chippers, or sawdust or chips, or mixtures of the above-mentioned organic matter, which add about 10% of the total volume of contaminated soil to the contaminated soil.

The drainage base is formed of a water-permeable material with a layer thickness of about 0.1 m. and which is intended for excess water in the pores of the soil exceeding its water capacity. and for rapid removal of the leachate leachate.

The soil to be cleaned is loaded approximately 0.5 m thick. Layers of this thickness are sufficiently well supplied with biogenic preparations, aerated and moisturized with about 0.1 m thick organic material interlayer insertion, aeration and wetting means. It uses, for example, straw as organic material for interlayer formation. To ensure a favorable temperature regime for microbiological cleaning of contaminated soil, the pile is formed approximately 2 m high. This pile produces favorable patterns of temperature (28 - 32 ° C) and humidity (65 - 75% of the water volume of the soil), which remain almost constant throughout the time of soil cleaning.

The microbiological treatment system for soil contaminated with oil or oil products consists of a drainage base formed on a watertight solid surface, above which layers of mixed organic soil contaminated with organic material interlayer form a pyramid-shaped pile, and organic material interstices. means for incorporation of biogenic preparations into the soil to be cleaned.

The system's irrigation, aeration, and biogenic agent insertion shingles are perforated polyethylene tubes arranged parallel to one another in the organic material interlayer.

The drainage system of the system consists of either a layer of concrete blocks with slopes at the top and slots at the bottom, or a layer of gravel containing perforated polyethylene pipes. The top slope and bottom recesses of the blocks used for drainage bases are made at the opposite edges of the block, so that when the blocks are compressed and the drainage base is formed, continuous filtrate drainage channels are formed.

Thus, the proposed method and system for microbiological cleaning of soil contaminated with oil and oil products enhances cleaning efficiency by cleaning large amounts of contaminated soil using soil microorganisms and facilitates their vital activity and biological activity. The method is simple, uses cheap, locally sourced raw materials and reduces the cost of the cleaning process.

For the implementation of the microbiological treatment of soil contaminated with oil and oil products, the proposed system is shown in the drawings, where:

FIG. Figure 1 is a cross-sectional view of a microbiological purification system for soil contaminated with oil or oil products.

FIG. Figure 2 is a cross-sectional view of a single block of drainage means layer.

The microbiological treatment of soil contaminated by oil or oil products is carried out by adding organic matter to the soil contaminated by oil or oil products, mixing the soil contaminated with organic matter, forming a drainage base on a non-watertight hard surface, applying a layer of cleaned soil Organic interlayer, places irrigation, aeration, and biogenic agents in the soil to be treated with the interlayer organic materials, and again reloads the soil layer to be cleaned. In this way, it charges the interlayer omo of organic material in turn until it forms a pile of soil for cleaning.

To improve the structure of the soil contaminated with oil or oil products, organic matter is added to it and then the soil contaminated is mixed. It uses inexpensive, locally sourced organic materials with a high content of cellulose, such as straw chippers, or chips or sawdust, or mixtures of these, to improve soil structure. These substances contain 50% or more of cellulose, which is degraded in soil by special microorganisms present in the soil and absorbing cellulose, such as Cytophaga tenuissirna, C. aurantiaca, Sporocytophaga rnyxococcoides, Sorangium cellulosiim, S. compositum, Vibrio flavescens up to gram polysaccharides - mucus. The mucus acts as a surfactant, helping to release the oil (fuel oil) from the surface of the soil particles and inside the soil microparticles, thereby facilitating the destruction of the oil-oxidizing microorganisms. These soil improvers add about 10 ° / o of the total volume of soil treated to the contaminated soil.

Hard ground coatings on soil treatment form a drainage substrate from the drainage layer. Drainage uses either specially constructed 0.5 mx 0.25 m rectangular concrete blocks, about 0.1 m high, which have a slope at the top to the side walls and slots at the bottom at opposite edges of the block so that the blocks compression and forming of the drainage base would result in continuous channels for rapid drainage of the filtrate (salva) or gravel layer with perforated polyethylene pipes spaced about 0.5 m apart. This drainage layer is required to remove excess water and to aerate the bottom layer of the soil to be cleaned. When drained using a layer of gravel with perforated polyethylene pipes placed in it, it forms up to 0.1 m in thickness, just like with a block layer.

It places a layer of ready-to-clean soil of up to 0.5 m thickness on the formed drainage base, then forms a horizontal layer of organic matter for which straw is best used, and in this layer lay perforated polyethylene pipes at intervals of about 50 cm diameter about 63 mm. This interlayer, with its perforated polyethylene pipes, is designed for irrigation, aeration and the insertion of biogenic preparations into the soil. In this way, the layers are stacked in succession with the organic layers, until they form a pile about 2 m high and the top layer is a layer of soil that has already been aerated naturally.

FIG. 1 shows a microbiological cleaning system for petroleum or petroleum-contaminated soil consisting of a waterproof solid pavement site 1 formed either of a gravel bed drainage base 2 or a concrete block drainage layer 3. A layer 4 of organic soil contaminated with oil or oil products is deposited on the drainage substrate, and an interlayer 5 of organic material is formed on the soil layer to be cleaned, such as straw. This organic material interlayer 5 comprises perforated polyethylene pipes 6 which, together with the organic material interlayer 5, are intended for irrigation, aeration and application of biogenic preparations to the soil being cleaned.

In the case where the drainage base 2 consists of gravel, it also contains perforated polyethylene pipes 6 for aeration of the bottom layer of the soil to be cleaned. The blocks 3 used for the drainage base have a slope at the top to the edges towards the side walls and a slit at the bottom as shown in FIG. 2, The grooves formed at the compaction points of the block-formed drainage base blocks are designed to transfer the filtrate to the filtrate collection tank (not shown in the drawings). The oil or petroleum-contaminated soil cleaning system thus formed is a pyramid-shaped pile with a drainage base of about 0.1 m, a soil layer of about 0.5 m in thickness, and a layer of organic material with perforated polyethylene pipes of about 0 m. , 1 m thick and pile height up to 2 m.

The advantage of the thick-cleaned soil layer is that the thick aerated soil layer creates favorable conditions for the aerobic decomposition of petroleum products and thus for the optimal temperature regime. The proposed method and system provide favorable conditions for the activity of microorganisms present in the soil to be cleaned to oxidize petroleum products, even without the use of special preparations of oil oxidizing microorganisms.

Because during aerobic degradation. due to intensive oxidation of organic materials, energy is released and the soil warms up, thus, during the treatment of contaminated soil, much heat is stored in the soil mass, which is used for intensification of the technological process. In this way, soil treatment in the pile (thick layer) creates much better conditions for oil-oxidizing microorganisms than other methods.

The method and system for microbiological cleaning of oil or oil contaminated soil are described in the examples below.

example

Production test of soil cleaning technology was carried out. 1,700 soils with a contamination of petroleum products of 12,000 - 19,000 mg / kg were treated. The qualitative soil pollution with oil products is as follows:

paraffin - naphthenic hydrocarbons -15% olefins and cyclodiolefins - 5% alkylilinonearomatic hydrocarbons - 1% alkyldiaromatic hydrocarbons - 4% polyaromatic hydrocarbons - 20% benzene resin - 30% alcohol-benzene resin - 25%

Organic matter (straw chop and sawdust) was added to the contaminated soil up to 10% of the cleaned soil volume and the soil was mixed with organic matter to ensure an even distribution of oil pollutants and organic matter on the concrete surface of the soil treatment site. a thick layer of gravel containing perforated polyethylene tubes of 63 mm diameter for draining leachate. The pile was formed by pouring contaminated soil into layers 0.5 m thick, 4-5 m wide and 60 m long. After applying one layer of treated soil, an organic interlayer was formed on it, namely a 5 cm thick straw layer and a ventilation layer of polyethylene perforated} 63 mm diameter pipes, which were covered with the same 5 cm thick layer of straw. The distance between horizontally arranged perforated polyethylene pipes is approximately 0.5 m. These interlayers are intended for better aeration of the soil by natural air circulation, as well as for the insertion of a solution of biogenic preparations and for irrigation of the soil. It should be noted that aeration also occurs when air enters the cleaned soil through its surface. Again, the same layer of cleaned soil, approximately 0.5 m thick, is loaded onto the specified ventilation layer. This loads the stack to a height of about 2 m. After completion of loading of the cleaned soil, the soil

Ί wetted with a solution of biogens, the amount of Biogenic elements is added based on their amount in the soil to be cleaned. The weight ratio of biogenic elements used in the production test was C: N: P: K - 100: 5 - 15: 1: 1. Used mineral fertilizers:

ammonium nitrate (NH4NO3) enriched floury superphosphate (CaH2PO ₄ · · Η2θ 2Οβ5θ4), potassium magnesium sulfate (K2SO4 »MgSO ₄₎

Biogenic elements are administered in 3 divided doses. They were dissolved in water for irrigating the soil to be cleaned. The means used (fertilization, drainage, aeration) stimulated the natural association of oil-oxidizing microorganisms (NOMs).

The soil to be cleaned was irrigated.

An air sensor located at the point furthest from the outer surface was used to measure the soil temperature in the pile. Temperature (28 - 32 ° C) and humidity (65 - 75% of the water volume of the soil) favorable for the technological process were formed in the cleaning soil.

Oil contamination of the filtrate (salva) was negligible during the whole soil cleaning period.

In the production test, most of the oil was destroyed within 2.5 months. The remaining petroleum products are degraded more slowly by 5 - 10% from baseline, more resistant to NOM enzyme.

Soil Removal Conditions: Concentration of petroleum products should not exceed 20,000 mg / 'kg (higher concentration acts as inhibitory NOM), pH of soil to be cleaned 8. The soil must be well mixed to ensure an even distribution of petroleum products and added organic matter. To improve the soil structure, it is inserted either with a straw chop, or with chips or sawdust, or a mixture of up to 10 ° soil volume; use oxidised nitrogen compounds, phosphorus, potassium, magnesium fertilizers (for concentration above) in the diet of micro-organisms that destroy oil.

example

A production test of a soil cleaning technology analogous to that described in Example 1, e.g. with the same soil contamination, with the same consistency in the formation of contaminated soil layers and using the same and the same amount of mineral nutrients, only the drainage gravel layer with its perforated polyethylene pipes for aeration of the soil by natural air circulation was used specifically made of rectangular 0.5 mx 0.25 m concrete blocks, about 0.1 m high, with a slope at the top to the side walls and a slit at the bottom. Grooves formed at the compression points of the block-formed drainage base blocks for transferring the filtrate to the filtrate (salva) collection tank. On the solid surface of the contaminated soil treatment site, a drainage base for these blocks was laid, on which, similarly to Example 1, a system of organic soil interlayers was formed.

The test showed that the drainage layer has the same filtering properties as fine clean sand (k - 0.0025 cm / s). The channels at the block junctions ensure rapid drainage of the filtrate (salva). Concrete blocks are mechanically resistant. All mechanized work is performed on the conductive substrate consisting of these blocks.

The tests carried out showed that both the gravel layer with the perforated polyethylene pipes for better aeration of the soil by natural air circulation, as well as the insertion of the solution of biogenic preparations in the pile drainage equipment are equally suitable, as well as concrete blocks.

The proposed method and system for microbiological cleaning of soil contaminated with oil and petroleum products provides favorable conditions for oil oxidizing microorganisms and allows efficient cleaning of large amounts of contaminated soil using cheap local organic materials at a minimal labor cost and economical utilization of production area of soil cleaning sites.

The aeration system of polyethylene perforated pipes is also suitable for subsoil irrigation and feeding of microorganisms with biogenic preparations together with water.

Claims (10)

DEFINITION OF INVENTION 1. A method of microbiological treatment of soil contaminated by oil or petroleum products by treating the soil contaminated with oil-oxidizing microorganisms under conditions which are optimal for their activity. to add organic matter to the contaminated soil, to mix the contaminated soil with organic matter, to form a drainage base on waterproof solid pavement sites, to stack the soil to be cleaned in layers with successive layers of organic matter, to which irrigation, aeration and biogenic agents are added cleaned primer means. 2. A process according to claim 1, wherein the organic materials added to the contaminated soil are high cellulosic material, 3. A process according to claim 2, wherein the organic materials added to the contaminated soil are either straw chippings or sawdust or chips or mixtures of said organic materials. 4. A process according to claims 1-3, wherein the organic matter is added to the contaminated soil to about 10% of the total contaminated soil volume. 5. A process according to claim 1, characterized in that the drainage substrate has a thickness of about 0.1 m, the thickness of the soil layers to be cleaned is about 0.5 m, the thickness of the interlayer organic material is about 0.1 m and the height of the formed pile is about 2 years 6. A process according to claim 1, wherein the interlayer organic material is preferably straw. 7. Microbiological purification system for soil contaminated with oil or oil products with drainage. wetting, aeration and application of biogenic agents to the soil to be cleaned, characterized in that the system consists of a drainage base formed on an impermeable solid coating site, above which layers of mixed organic soil contaminated with organic material interlayer are formed to form a cut pyramid; means for wetting, aeration and incorporation of biogenic preparations into the soil to be cleaned. 8. A system according to claim 7, characterized in that the irrigation, aeration and insertion of biogenic preparations are perforated polyethylene pipes arranged in organic layers. d. The system of claim 7, further comprising. that the drainage base consists of either a layer of concrete blocks with slopes at the top and slots at the bottom, or a layer of gravel containing perforated polyethylene pipes. 10. A system according to claim 9, characterized in that the top slope and bottom recesses of the drainage base block are made at opposing edges of the block so that continuous drainage channels of the filtrate are formed when the blocks are compressed and the drainage base is formed.