RU2792986C1 - Method for cleaning oil-contaminated surface soil - Google Patents

Abstract

FIELD: environmental protection.

SUBSTANCE: mechanical (hydraulic) method for cleaning soil from oil or oil products contaminated due to accidental spills. Method for cleaning oil-contaminated soil includes arranging an embankment 1 along the perimeter of the surface soil 5 contaminated with oil products and constructing wells 2 along the perimeter outside it, into which pipes 3 with impermeable walls and an open bottom are laid. These pipes 3 are used for bottom injection of water and to maintain the water level in the pipes above the level of the day surface 4 of the contaminated soil 5. From the side of the embankment 1, through wells 2 under the contaminated soil 5, opposite directed low-pressure filtration flows of water 7 are created, from which a water-saturated oil-impermeable layer is formed. Then, from this layer above the watertight boundary 6, a depression surface 8 of the filtration flow of water 7 is created, having an upward bulge 9 in the central part of the surface. Oil products from the contaminated soil 5 are displaced to the level of the day surface 4 due to the upward movement of the surface of the depression 8 and the growth of its convexity 9, while the oil products are distributed on the contaminated soil along its periphery. Oil products are pumped out from the level of the day surface 4 also along the periphery of the contaminated soil. Thus, the above implementation of the method provides a better collection of oil products at an increased concentration of oil products in the collected volume, since they are not intensively mixed with water.

EFFECT: invention provides less impact on the natural landscape during the preparation and collection of oil products and reduces material costs.

1 cl, 3 dwg

Description

The invention relates to the field of environmental protection, in particular to a mechanical (hydraulic) method for cleaning soils and soils from oil or oil products contaminated due to accidental spills.

There is a known method of cleaning soil contaminated with oil or oil products (RF patent No. 2295402 C2, IPC V09S 1/00, published on March 20, 2007), in which the place of pollution is dredged, water is supplied to the underlying aquifer from the ditch created behind the ditch under pressure, and soil is raised. water to displace oil products on the surface. At the same time, in the middle of the pollution, at least through one well, water is supplied under pressure into the underlying aquifer.

The disadvantages of this method are: the need for construction in the center of contamination of wells; when using additional equipment to create water pressure and heavy equipment in the difficult zone of unsteady soils for drilling wells, the top layer of soil is mixed; the natural filtration process is disrupted; the impact of oil products on the root system of plants is aggravated.

A known method for collecting and removing oil products from the surface of groundwater (RF patent No. 2162916 C1, MPK ⁷ E02B 11/00, 15/04 published on February 12, 2001), according to which two dams are created one after the other around the contaminated area along the perimeter, in the space between dams supply water, saturate the soil with water, and the displaced oil products are collected in the center of the pollution zone through a buried drainage device.

The disadvantages of this method are: the need to build a drainage device in the center of pollution; it is necessary to transport it to the center of the contaminated zone, to lay it along the contaminated section of the pipeline; the top layer of the soil is mixed at the same time, thereby disrupting the natural filtration process; the impact of oil products on the root system of plants is aggravated.

The closest technical solution adopted for the prototype is a method of cleaning the surface and underlying rocks from oil products (RF patent No. 2238806 C1, IPC ⁷ V09S 1/00, published 27.10.2004). According to this method, an embankment is arranged along the perimeter of the oil spill, inside which water is supplied and the internal space of the embankment is filled with it. Wells are constructed outside the contour of the embankment and inside it, through which the water-oil mixture is pumped out.

The disadvantages of this method are: the construction of wells on soil contaminated with oil products and the laying of pipelines to wells along contaminated soil, which leads to a violation of the structure of the soil and the natural process of filtering liquids. The supply of water to the oil spill zone leads to the mixing of water with oil products that have a lower density, and the natural settling process is disturbed. Oil products along with water are carried down when pumping through the lower section of the well. Additional equipment is required to separate the pumped mixture into water and oil products. Due to the fact that oil products are lower in density than water, most of them will rise up, which complicates the surface cleaning process.

The task to be solved by the present invention is to improve the quality of cleaning soil contaminated with oil products while maintaining the natural structure of the soil layer and the root system of vegetation.

The technical result consists in creating a depression surface of a filtration flow of water under a surface soil contaminated with oil products, having a bulge upwards in the central part of the surface, and displacing oil products to the level of the day surface by moving the surface of the depression upwards and increasing its bulge. Due to the increase in the convexity of the depression surface, oil products are distributed on the soil contaminated with oil products along its periphery. Oil products are pumped out from the level of the day surface of the contaminated soil also along its periphery.

The specified technical result is achieved by the fact that an embankment is arranged along the perimeter of the contaminated soil and a well is constructed outside the contaminated soil beyond the perimeter of the embankment, into which pipes with impermeable walls and an open bottom are installed. Through these pipes, the bottom injection of water into the uncontaminated soil and soil is ensured and a constant water level in the pipes is maintained, exceeding the level of the day surface of the soil contaminated with oil products. Under the soil contaminated with oil products from the side of the embankment, through the wells, counter directed low-pressure filtration water flows are created, from which a water-saturated oil-impermeable layer is created. Then, from this layer above the impermeable boundary, a surface of the depression of the filtration flow of water is created, having a bulge upward in the central part of the surface, and oil products are displaced to the level of the day surface by moving the surface of the depression upward and increasing its bulge. Due to the increase in the convexity of the depression surface, oil products are distributed on the soil contaminated with oil products along its periphery. Oil products are pumped out from the level of the day surface of the contaminated soil also along its periphery.

From the patent scientific and technical literature, a specialist does not know a method in which an embankment is arranged along the perimeter of soil contaminated with oil products, wells are built outside the perimeter of the embankment, through which water is supplied and a depression surface of the filtration flow of water is created, having a bulge upward in the central part of the surface, to displace oil products to the level of the day surface of the contaminated soil, and oil products are distributed on the contaminated soil along its periphery, and oil products are pumped out from the level of the day surface of the soil also along its periphery.

The method of cleaning the soil contaminated with oil products is illustrated by drawings, which shows a schematic diagram of the implementation of the cleaning method.

In FIG. 1 - shows a scheme of saturation with counter directed low-pressure filtration flows of soil water under oil-contaminated soil.

In FIG. 2 - a diagram of the formation of a surface depression of the filtration flow of water under the soil contaminated with oil products with a convexity of the surface upwards in its central part.

Figure 3 - shows a diagram of the displacement of oil by moving up the surface of the depression and the growth of its convexity.

The method for cleaning oil-contaminated surface soil is based on creating an embankment 1 (Fig. 1) along the perimeter of the oil-contaminated soil 5, and constructing along the perimeter outside the embankment 1 the oil-contaminated soil 5 wells 2, into which pipes 3 with impermeable walls and an open bottom are installed. Pipes 3 are connected to water hoses (not shown in Fig.). During the preparatory work, embankment I is constructed with a height of, for example, 0.15-0.25 m. cover. When constructing wells 2, a drill having a diameter of, for example, 125-150 mm is used. The drilling depth can be, for example, 0.5-1.0 m. The distance between the boreholes 2 can be, for example, 5-10 m.

According to the diameter of wells 2, pipes 3 with impermeable walls and an open bottom are selected. The upper ends of the pipes 3 protrude from the wells 2 to a height, for example, comparable to the height of the embankment 1 and are connected through water hoses (hoses) to a pressure water line, which in turn is connected to a pumping unit (not shown in Fig.). To regulate the water level in pipes 3, valves and taps are used to block the flow area of water pipes (not shown in Fig.).

Any known technology can be used for pumping oil products from soil 5 contaminated with oil products: using sewage trucks, pipelines, etc.

The method of cleaning oil-contaminated surface soil is as follows. Along the perimeter of the soil 5 contaminated with oil products, an embankment 1 is arranged (Fig. 1). Wells 2 are constructed along the perimeter outside the embankment. Pipes 3 are installed in the wells, and then they are connected to water pipes (not shown in the diagram). Water is supplied through pipes 3, providing bottom injection into uncontaminated soil 10 (Fig. 1). To do this, a constant water level is maintained in the pipes 3, exceeding the level of the day surface 4 of the contaminated soil 5. The water level in the pipes 3 is adjusted using valves, taps (not shown in the figure).

The uncontaminated soil 10 (FIG. 2) under the contaminated soil 5 is saturated with water. Due to the fact that water is injected into uncontaminated soil 10 along the perimeter of contaminated soil 5, and a constant water level is maintained in pipes 3, counter directed low-pressure filtration water flows 7 are formed under the contaminated soil 5 above the watertight boundary 6 (Fig. 2).

Under the waterproof boundary 6 is understood the boundary between the waterproof soil (clay, loam) and the overlying soil. A waterproof boundary should also be considered the boundary between the groundwater level and the overlying soil (in the absence of clay, loam).

After the meeting of directed low-pressure filtration flows of water 7 (Fig. 2) in the central part under the contaminated soil 5 from this water-saturated layer above the waterproof boundary 6, by maintaining a constant water level in the pipes 3, a depression surface 8 of the filtration flow of water 7 is created, having a convexity upwards 9 in the central part of the depression surface.

At the next stage (Fig. 3), while maintaining the water level in the pipes 3 above the level of the day surface 4 of the soil contaminated with oil products 5, the surface of the depression 8 with a bulge 9 reaches the lower level of the contaminated soil 5 and begins to displace oil products from it.

Since oil products have a lower density compared to water, and water filtration flows 7 (Fig. 3) are low-pressure, oil products are displaced from contaminated soil 5 and rise without mixing with water, which is saturated with soil below the surface of depression 8.

The displacement of oil products from the contaminated soil 5 (Fig. 3) by the depression surface 8 with a bulge 9 and the upward growth of this bulge in the central part of the contaminated soil leads to the distribution of oil products along the periphery of the contaminated soil 5.

This creates favorable conditions for the subsequent pumping of oil products from the level of the day surface 4. Oil products are located in the surface layer of the day surface along its periphery. There is no need to build wells on soil 5 contaminated with oil products, lay pipelines through it, and transport process equipment through it. All the equipment necessary for pumping out oil products is located outside the soil contaminated with oil products 5.

Thus, the above implementation of the method provides a better collection of oil products at an increased concentration of oil products in the collected volume, without damaging the structure of the natural soil layer and the root system of vegetation. The inventive method provides a minimal negative impact on the natural landscape during the preparation and collection of oil products without the possible involvement of heavy equipment at very limited material costs.

The proposed technical solution can be used in various industries by consumers of petroleum products and in case of emergency situations on oil pipelines, it will increase the efficiency of surface cleaning from petroleum products.

Claims (1)

A method for cleaning surface soil contaminated with oil products, in which an embankment is arranged along the perimeter of the contaminated soil, wells are constructed, oil products are displaced from the soil, characterized in that the wells are built outside the soil contaminated with oil products beyond the perimeter of the embankment, pipes with impermeable walls and an open bottom are installed in the wells, through pipes provide bottom water injection, maintain a constant water level in the pipes, exceeding the level of the day surface of the contaminated soil, create under the contaminated soil from the side of the embankment through the wells, counter directed low-pressure filtration water flows, from which a water-saturated oil-impermeable layer is created, from this layer above the water-impermeable boundary they create the surface of the depression of the filtration flow of water, which has a bulge upward in the central part of the surface, displace oil products to the level of the day surface due to the upward movement of the surface of the depression and the growth of its bulge, distribute oil products on the soil contaminated with oil products along its periphery, pump out oil products from the level of the day surface of the contaminated soil also on its periphery.

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