RU2602615C2 - Method of soil cleaning from hydrocarbons and pesticides and device for its implementation - Google Patents

Abstract

FIELD: ecology.

SUBSTANCE: invention relates to environmental protection, namely to reclamation of lands, contaminated with hydrocarbons (oil products), decontamination of soil from pesticides using phenomenon of electric osmosis. Method of cleaning soil from oil products and pesticides using electroosmosis consists in immersing of central and peripheral electrodes into soil at section, undergoing cleaning, creation of non-uniform electric field between central and peripheral electrodes, supplying of non-contaminating carrier fluid into area adjoining central electrode, movement of carrier fluid under action of electroosmotic effect from central electrode to peripheral ones, removal of dirt beyond contaminated section, displacement of contaminants from soil by carrier fluid and removal thereof from peripheral electrodes, non-uniform electric field intensity value is set within 50-110 kV/m, before supplying carrier fluid soil is milled into particles of 1.0 mm in depth of 20-25 cm. Milled soil is mixed with carrier fluid to concentration of 1:6. Fluidized layer is created by device in depth of 10-12 cm with supply of compressed air of pressure 1-2 ATM. Proposed device comprises central electrode and system of peripheral electrodes, submerged into soil cleaning section, nozzle for carrier fluid supply and removal of fluid, containing contaminants, from cleaning section. Central electrode is made in form of rod with cross section in form of polygon with concave sides. System of peripheral electrodes is composed by separate rods. Rods are connected by wire conductors with sharp-pointed elements on them, point of which is directed to central electrode. Ahead of nozzles for supply of carrier fluid dispenser is placed. Above system of peripheral electrodes device for creation of fluidized layer is located, including central r-shape pipeline with compressor, connected via control valve with system of radial pipelines, at end of each of which nozzles are located, submerged into soil for depth of 10-12 cm.

EFFECT: proposed method of soil cleaning from hydrocarbons and pesticides and device for it provide maximum effect of soil cleaning.

2 cl, 1 tbl, 2 dwg

Description

The invention relates to the protection of the environment, namely the reclamation of land contaminated with hydrocarbons (oil products), neutralizing the soil from pesticides using the phenomenon of electroosmosis.

With the expansion of the use of pesticides, a number of the following negative consequences were revealed: pollution of soils and water sources, accumulation of chemical residues in food products. In the soil, pesticides decompose as a result of both physicochemical processes and microbiological decomposition. Pesticide residues in the soil are washed out by storm and soil waters, gathering in natural water bodies, pollute them, as well as the surrounding land.

The problem of cleaning land and soil for agricultural purposes, the disposal of excess pollutants, especially stored in an open way, is especially relevant for modern ecology. Currently, herbicides as well as organochlorine pesticides: fusid-forte, Zenkor, chistoplan, puma-super are widely used in agricultural production technology.

There is a method of cleaning a capillary-porous medium contaminated with oil and oil products by introducing a solution of oil-oxidizing microorganisms into the cleaning zone, introducing an electrically conductive liquid, passing electric current to create electroosmosis (RU 96115094 A, IPC B09C 1/10, published on November 27, 1998. )

A known method of in situ restoration of contaminated (heterogeneous) soils of various composition and properties, including introducing material for cleaning contaminants into a heterogeneous soil region, passing a direct electric current between electrodes within a contaminated heterogeneous soil, applying a hydraulic gradient across the pollution region (RU 2143954 C1, IPC B09C 1/08, publ. 10.01.2000).

The disadvantage of the above analogues is the complexity of their use and the insufficient degree of purification of the soil from pollution.

The closest analogue of the method adopted as a prototype is a method of cleaning the soil, including immersion in the soil on the cleaned area of the Central and peripheral electrodes, the creation of a voltage gradient between the Central and peripheral electrodes, feeding into the area adjacent to the Central electrode, not polluting the carrier fluid , the movement of the carrier fluid under the action of the electroosmotic effect from the central electrode to the peripheral, the displacement of hydrocarbons from the soil by the carrier fluid, removal x of the peripheral electrodes, creating an uneven electric field between the central and peripheral electrodes (RU 2508954 C1, IPC B09C 1/00, publ. 10.03.2014 g).

The disadvantage of the prototype is the insufficient degree of purification of the soil from hydrocarbons, since cleaning when using electroosmosis is carried out in an insufficiently strong uneven electric field, as well as the lack of effective purification from pesticides.

A device for applying a method for cleaning contaminants of a capillary-porous medium, including a chamber for accommodating the medium to be cleaned with electrodes connected to a direct current source, a container with a liquid to be cleaned and a container for waste liquid (RU 2106432 C1, IPC ⁶ C25C 1/22, publ. March 10, 1998).

A known installation for processing soils, soils (RU 2330734 C1, IPC B09C 11/00, published on 08/10/2008), containing a hopper with a mixing device, with a device for transporting liquid from it to the overflow tank and a device for outputting solid inclusions, washing fluid supply system, vibrator.

The disadvantage of the above analog devices is also the insufficient degree of soil purification from contamination.

Closest to the proposed device for implementing the method adopted as a prototype is a device containing a central electrode and a system of peripheral electrodes immersed in the soil of the cleaning zone, nozzles for supplying carrier fluid, pumps for pumping liquid into nozzles and removing liquid containing contaminants from cleaning zone, the central electrode is made in the form of a rod, the cross section of which is a polygon with concave sides (RU 2508954 C1, IPC B09C 1/00, publ. 03/10/2014).

The disadvantage of the prototype is the ineffective cleaning of the soil from hydrocarbons (oil products) and the lack of purification from pesticides.

The objective of the proposed method and device for its implementation is to increase the degree of soil purification from hydrocarbons (petroleum products), as well as cleaning the soil from pesticides.

The technical result of the application of the method of cleaning the soil from hydrocarbons and pesticides is achieved due to the fact that it includes immersion in the soil on the cleaned area of the central and peripheral electrodes, creating an uneven electric field between the central and peripheral electrodes, supplying a non-polluting liquid to the region adjacent to the central electrode -carrier, the movement of the carrier fluid under the action of the electroosmotic effect from the central electrode to the peripheral electrode, displacement from the soil by the liquid-n with contaminants and removing them from the peripheral electrodes, but, unlike the prototype, the magnitude of the uneven electric field is set in the range of 50-110 kV / m, before grinding the carrier fluid, the soil is crushed using a serial cultivator in the form of a disk cutter to the particle size 1.0 mm at a depth of 20-25 cm, the crushed soil is mixed with the carrier fluid to a concentration of 1: 6 controlled by the dispenser, using an additionally installed device, a fluidized bed with a depth of 10-12 cm with a supply of compressed air pressure of 1-2 atm.

The technical result of the application of the device for cleaning the soil from hydrocarbons and pesticides is achieved due to the fact that it contains a central electrode immersed in the soil of the cleaning zone in the form of a rod with a cross section in the form of a polygon with concave sides and a system of peripheral electrodes made of separate rods, nozzles for feeding carrier fluid, pumps for injecting fluid into nozzles and removing fluid containing contaminants from the cleaning zone, unlike the prototype, the system of peripheral electrodes of soy they are interconnected by wire conductors with pointed elements fixed on them, the tip of which is directed to the central electrode, a dispenser is installed in front of the nozzles for supplying carrier fluid, and a device for creating a fluidized bed including a central L-shaped pipeline with a compressor is installed above the peripheral electrode system, connected through a distributor to a system of radial pipelines, at the end of each of which nozzles are installed, immersed in soil to a depth of 10-12 cm.

The prior art does not know the influence of a new set of features of the claimed method and device on achieving a new technical result - cleaning the soil from pesticides, which allows us to conclude that technical solutions meet the criteria of "novelty" and "inventive step".

Cleaning the soil from hydrocarbons and pesticides is as follows. A voltage gradient is created between the central and peripheral electrodes on the soil to be cleaned, the magnitude of the uneven electric field is set within 50-110 kV / m, the carrier fluid is supplied to the region adjacent to the central electrode, the carrier fluid is moved under the action of the electroosmotic effect of the central electrode to the peripheral, oil products are displaced from the soil using a carrier fluid and removed from the peripheral electrodes.

Before feeding the carrier fluid to increase the degree of purification of the soil from hydrocarbons and pesticides, the soil is crushed using a serial cultivator in the form of a disk mill to a particle size of 1.0 mm at a depth of 20-25 cm. The depth of soil grinding depends on the penetration depth of pesticides, and this is determined by the depth of plowing, and according to the processing technology of various crops averages 10-12 cm. To create a fluidized bed to a depth of 10-12 cm, it is necessary to grind the contaminated soil with a cultivator, respectively, to a depth of two times that is 20-25 cm.

If the particle size is larger than 1.0 mm, then with the formation of a fluidized (boiling) layer of soil, consisting of drops of water and air bubbles, the particles will undergo sedimentation faster and settle in the area without adequate cleaning. If the particle size is less than 1.0 mm, then the particles will migrate in the water-air phase.

The crushed particles of the soil are mixed with the carrier fluid to a concentration of 1: 6, which is determined by the flow rate of water through the circulation pump of the carrier fluid and the dispenser. If the concentration of soil particles in the liquid phase is more than 1: 6, then a suspension between the solid and liquid phases will not form. Conversely, if the concentration of soil particles in the liquid phase is less than 1: 6, then in the resulting suspension of soil particles will not be enough to implement the method.

If the pressure of compressed air is less than 1-2 atm, then the resulting fluidized bed cannot penetrate to a depth of 10-12 cm, if the pressure of compressed air is more than 1-2 atm, the depth of the fluidized bed will be more than 10-12 cm, which will lead to increased consumption of compressed air and energy costs for its production.

The efficiency of soil cleaning from hydrocarbons and pesticides increases due to the physical processes that occur during the interaction of the fluidized bed with an uneven electric field of the indicated intensity, which occur as follows.

It is known that when the carrier liquid is saturated with air in a ratio of 1: 6 (in our case), air bubbles are created in the liquid phase. Under the influence of an uneven electric field between the pointed elements of the peripheral electrodes and the central electrode, air bubbles are aligned along the field lines of force, then they are elongated along the lines of force and reduced in the transverse direction. Compression of the bubble in the transverse direction means that compressive forces act near its equator. In this case, the air bubble behaves like a dielectric, the field inside it is slightly distorted. Further, it increases in all directions with the formation of a primary streamer that flies out of its tip (Korobeinikov S.M. On the role of bubbles in the electrical breakdown of liquids. Thermophysics of high temperatures, 1998, No. 3, pp. 362-367, 1998 No. 4, from 541-547). A streamer is an ionized channel obtained by overlapping individual electron avalanches that arise in its path. The formation of streamers is accompanied by shock waves, the center of which is the origin of the streamers, that is, the tip of the bubble. During the development of the streamer channel, the surface of the bubbles appears to be charged, a volume discharge develops over the surface of the bubbles as a result of the action of the streamers in a two-phase medium (a mixture of water and soil), ozone and a number of active particles are generated, including the OH radical, atomic oxygen, etc. The resulting ozone decomposes pesticides, up to mineralization. In addition, hard plasma ultraviolet radiation occurs. Also, during the development of electrical breakdown, a powerful shock wave is formed, which has an additional disinfecting effect on the soil.

It is known that the electric field E of a charged cylinder of radius r is determined by the formula (1) (NI Koshkin. Handbook of elementary physics. - M .: Nauka, - 1980):

where k is the coefficient of proportionality, k = 8.9875 ∗ 10 ⁹ m / F;

q is the electric charge, q = 2.3467 ∗ 10 ^-2 C;

r is the radius of the cleaning zone;

ε is the dielectric constant of the medium.

It is known that, depending on the amount of humus, the amount of water, the viscosity of the soil, the dielectric constant of the soil is ε = 19.2; 23.8; 26.7; 41.2 (Bobrov P.P., Belyaeva T.V. Experimental verification of the model of complex dielectric permeability of soils and soil moisture viscosity. // Natural Sciences and Ecology. Omsk GPU Yearbook. 2002. - pp. 29-33).

The results of calculating the electric field strength by the formula (1) for r = 10 m are given in table. one.

Calculations show that for a given range of 19.2 to 41.2 changes in the dielectric constant of the soil, the electric field strength is from 50 to 110 kV / m.

In FIG. 1 shows a diagram of a device for implementing a method of cleaning the soil from hydrocarbons and pesticides, FIG. 2 - a device for creating a fluidized bed.

Figure 1 shows a diagram of a device for implementing the method, figure 2 is a device for creating a fluidized bed

The device diagram (Fig. 1) shows: the zone of the cleaning layer 1, the central electrode (anode) 2 immersed in the soil of the cleaning zone 2, the system of peripheral electrodes (cathodes) 3, the nozzle 4 for supplying the carrier fluid, the dispenser 5 to create a controlled concentration of liquid -carrier, pump 7 for removing liquid containing oil products from peripheral electrodes, pump 6 for pumping carrier fluid into nozzle 4 through dispenser 5, pump 9 for pumping contaminants containing oil products and pesticides from perforated pipe 8.

The system of peripheral electrodes is made of separate rods 3, interconnected by wire conductors 11 (Fig. 2) with the pointed elements 10 located on it, the tip of which is directed to the central electrode. To grind the soil using a serial cultivator in the form of a disk cutter. Above the system of peripheral electrodes, a device 12 for creating a fluidized bed is installed, including a central L-shaped pipe 13 with a compressor 14 connected through a distributor 15 to a system of radial pipes 16, at the end of which there are mounted nozzles 17 for supplying compressed air to the fluidized bed immersed in the soil to a depth of 10-12 cm.

The proposed method of cleaning the soil is carried out using the device as follows.

A serial cultivator in the form of a disk cutter grinds the soil to a particle size of 1.0 mm. In the soil crushed to a depth of 20-25 cm, the pump 6 serves through the nozzle 4 the carrier fluid.

Turn on pumps 6 and 7. Next, the crushed soil is mixed with the carrier fluid using pump 6 and dispenser 5 to a concentration of 1: 6. A voltage is applied to the electrodes 2 and 3, the value of which is set within 50-110 kV / m, as a result of which an uneven electric field is created between the protrusions of the central electrode and the pointed elements. The carrier fluid under the influence of the electroosmotic effect flows from the central electrode 2 to the system of peripheral electrodes 3, sorbing oil products or pesticides on its way, then the contaminants are removed by the pump 7.

The fluidized bed using the device is created as follows. Compressed air is injected from the compressor 14 through a central L-shaped pipe connected through a distributor 15 and a system of radial pipes 16 to nozzles 17 into the cleaning zone under a pressure of 1-2 atm. and air bubbles arise. In this case, under the influence of a non-uniform electric field between the pointed elements of the peripheral electrodes 3 and the central electrode 2, the alignment of air bubbles along the lines of force occurs. Then, at the tip of the bubble, a streamer forms, which flies into the cleaning zone. As a result of the action of streamers in a two-phase medium, ozone and a number of active particles (OH radical, atomic oxygen, etc.) are generated. The resulting ozone decomposes pesticides up to their mineralization.

As a result, the degree of soil purification from hydrocarbons (oil, oil, fuel oil, etc.) and pesticides rises to 98-99%.

Claims (2)

1. A method of cleaning the soil from hydrocarbons and pesticides, including immersing in the soil on the cleaned area of the central and peripheral electrodes, creating an uneven electric field between the central and peripheral electrodes, supplying a non-contaminating carrier fluid to the region adjacent to the central electrode, moving the carrier fluid under the influence of the electroosmotic effect from the central electrode to the peripheral, the removal of contaminants outside the contaminated area, the displacement of soil from the carrier fluid m of contaminants and their removal from peripheral electrodes, characterized in that the magnitude of the uneven electric field is set in the range of 50-110 kV / m, before the feed of the carrier fluid, the soil is crushed using a cultivator to a particle size of 1.0 mm at a depth of 20 -25 cm, crushed soil is mixed with a carrier fluid to a concentration of 1: 6, using the device create a fluidized bed with a depth of 10-12 cm with a supply of compressed air with a pressure of 1-2 atm, in which the contamination decomposes in The formation of streamers under the influence of an uneven electric field of high intensity. 2. A device for cleaning the soil from hydrocarbons and pesticides, containing cleaning zones immersed in the soil, a central electrode in the form of a rod with a cross section in the form of a polygon with concave sides and a system of peripheral electrodes made of separate rods, nozzles for supplying carrier fluid, pumps for pumping liquid into nozzles and removing liquid containing contaminants from the cleaning zone, characterized in that the peripheral electrode system is interconnected by wire conductors with fixed and on them with pointed elements, the tip of which is directed to the central electrode, a dispenser is installed in front of the nozzles for supplying a carrier fluid, and a device for creating a fluidized bed comprising a central L-shaped pipe with a compressor connected through a distributor to the radial system is installed above the peripheral electrode system pipelines, at the end of each of which nozzles are installed, immersed in soil to a depth of 10-12 cm.

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