Method for remediation of contaminated lands

Abstract

The invention relates to agriculture and can be used to restore soil fertility. A method for remediation of contaminated lands involves pouring and introducing a bioreagent to a depth into the soil prepared for purification. Remediation is carried out in 2 steps: in the first step, slit-like or round holes are made in the infected area to a depth of 25 cm, poured with water, afterwards, 5-6 hours later, this area is poured with a bioreagent in the form of a humus-containing suspension in an amount of up to 400 g per kg of soil containing strains: Acinetobacter calcoaceticus VKPM V-4883, Pseudomonas denitrificans VKPM-4884, Pseudomonas sp. “longa” VKPM V-4885, Rhodococcus erythropolis in an amount of (6-8).Math.10.sup.9, (3-4).Math.10.sup.9 (2-3).Math.10.sup.9, (1-2).Math.10.sup.9 cells per 1 L of solution, respectively, in the ratio, wt. % 4.8:2.4:1.7:1.0. In the second step, 8-10 days later, half the initial dose of the concentrate of the humus-containing suspension is introduced. After introduction of the second reduced dose of the humus-containing suspension, watering is continued for 14 days. The distance between the slit-like or round holes is 8-10 cm. The proposed method for remediation of contaminated lands provides for treatment efficiency and a reduction in the degree of decontamination from a high degree of contamination to the MPC (maximum permissible concentration) level, preservation of soil biocenosis and restoration of soil fertility.

Claims

1. A method for remediation of contaminated lands, consisting of: i) making slit-like or round holes in soil contaminated with soluble fluorine salts to a depth of 25 cm, ii) pouring the contaminated soil with water, iii) 5-6 hours later, pouring the soil with a bioreagent in the form of humus-containing suspension in an initial dose of an amount of up to 400 g per kg of soil containing strains: Acinetobacter calcoaceticus VKPM V-4883, Pseudomonas denitrificans VKPM-4884, Pseudomonas sp. VKPM V-4885, Rhodococcus erythropolis in an amount of 6-8×10.sup.9, 3-4×10.sup.9, 2-3×10.sup.9, and 1-2×10.sup.9 cells per 1 L of solution, respectively, in the ratio (wt. %) of 4.8:2.4:1.7:1.0, iv) pouring the contaminated soil with water, and, v) 8-10 days later, half the initial dose of the humus-containing suspension is introduced, and water pouring is continued for 14 days.

2. The method for remediation according to claim 1, wherein the distance between the slit-like or round holes is 8-10 cm.

Description

(1) The purpose of the claimed invention is to develop a technology of biological remediation of contaminated soils that would ensure the lowest manufacturing costs.

(2) The technical result of the proposed method is treatment efficiency and reducing the degree of decontamination from a high degree of contamination to the MPC level, maintaining soil biocenosis and restoring soil fertility, improving the environment in industrial cities and restoring disturbed lands, returning them to agricultural circulation.

(3) The purpose is achieved by the fact that in the method for remediation of contaminated lands, which consists in pouring and introducing an appropriate type of bioreagent to depth into the soil prepared for purification, remediation is carried out in 2 steps: in the first step, slit-like or round holes are made in the infected area to a depth of 25 cm, poured with water, afterwards, 5-6 hours later, this area is poured with the bioreagent in the form of humus-containing suspension in an amount of up to 400 g per kg of soil containing strains: Acinetobacter calcoaceticus VKPM V-4883, Pseudomonas denitrificans VKPM-4884, -Pseudomonas sp. “longa”, VKPM V-4885, Rhodococcus erythropolis in an amount of (6-8).Math.10.sup.9, (3-4).Math.10.sup.9 (2-3).Math.10.sup.9, (1-2).Math.10.sup.9 cells per 1 L of solution, respectively, in the ratio, wt. %, 4.8:2.4:1.7:1.0, afterwards, the infected area of land is poured with water, and in the second step, 8-10 days later, half the initial dose of the concentrate of the humus-containing suspension is introduced, after introduction of the second, reduced dose of the humus-containing suspension, water pouring is continued for 14 days. The distance between the slit-like or round holes is 8-10 cm.

(4) To achieve the technical result in the method for producing the biopreparation for purification and restoring fertility of soils contaminated with oil products, based on a filler and bacterial cultures, according to the invention, a mixture of liquid bacterial cultures is prepared, which are represented by the following strains: Acinetobacter calcoaceticus VKPM-4883 strain, Pseudomonas denitrificans VKPM 4884, strain, Pseudomonas sp. “longa” VKPM-4885, strain and, Rhodococcus erythropolis in an amount of (6-8).Math.10.sup.9, (3-4).Math.10.sup.9, (2-3).Math.10.sup.9, (1-2).Math.10.sup.9 cells per 1 litre of solution, respectively, in the ratio, in %, 4.8:2.4:1.7:1.0 and oxidized brown coals pre-screened from particles larger than 5 mm. The nutrient mixture for inoculating it with microorganisms consists of oxidized brown coal and nitrogen- and phosphorus-correcting additives. Said bacteria were produced by long adaptation of the association of soil microorganisms that oxidize carbon-containing substrates.

(5) The strain Acinetobacter calcoaceticus is grown for 2 days at 28° C. on a nutrient agar with the following composition: agar 2%, peptone 0.5%, sodium acetate 0.5%, yeast hydrolyzate-0.5%, dist. water is the rest, pH 7.0.

(6) The strains Pseudomonas denitrificans and Pseudomonas sp. “longa” are grown for 2 days at a temperature of 28 degrees on a nutrient agar with the following composition: glucose 1%, yeast hydrolyzate 0.5%, dipotassium phosphate 0.1%, diammonium phosphate 0.1%, magnesium sulphate 0.05%, calcium chloride 0.01%, agar 2%, iron sulphate and sodium chloride—traces, the rest is distilled water, pH 7.0.

(7) The strain Rhodococcus erythropolis is grown on a mash—agar, MPA (meat-and-peptone agar), on Raymond's medium, for 22 hours at a temperature of 28-32 degrees, pH 6.8-7.2. Together, the strains have a high fermentation ability to decompose carbon-containing substrates, including sooty brown coals.

(8) The raw biomass is washed off from the colonies of microorganisms grown on a nutrient agar with distilled water to a fermentation vessel, determining beforehand the number of cells under a microscope. Afterwards, the nutrient mixture consisting of sooty brown coals with additives, micro- and macroelements in the composition of sooty coals, is inoculated with the mixture of bacterial strains, in the ratio 4.8:2.4:1.7:1.0 with active stirring in the presence of atmospheric oxygen, adding water and at a temp. of 20-25 degrees for 25-28 hours until the number of strains in this mixture is reached: strain No. 10, Pseudomonas denitrificans VKPM 4884, Pseudomonas sp. “longa” VKPM-4885, and Rhodococcus erythropolis in an amount of (6-8) 10.sup.9, (3-4) 10.sup.9, (2-3) 10.sup.9, (1-2) 10.sup.9 cells per 1 litre of solution, respectively, in the ratio, wt. % 4.8:2.4:1.7:1.0.

(9) All said strains used in the claimed method for remediation of contaminated lands: Acinetobacter calcoaceticus VKPM V-4883, Pseudomonas denitrificans VKPM-4884, Pseudomonas sp. “longa”, VKPM V-4885, have been deposited in NBC VKPM (National Bioresource Center “All-Russian Collection of Industrial Microorganisms”), are viable, the certificate copies are enclosed.

(10) Rhodococcus erythropolis is not new, the fact that it is known is confirmed in an article in Multitopic Online Electronic Scientific Journal of Kuban State Agrarian University, 2012, UDC 579.6.

(11) The article deals with biotechnological properties of the oil oxidizing strain Rhodococcus erythropolis B2, which allow it for being used as a basis for a biopreparation: a degradative potential towards hydrocarbons, characteristics of growth on various media, production of phytohormones and biological surfactants, adhesive activity and floatability, tests in a laboratory environment and in the field.

(12) In addition, the strain Rhodococcus erythropolis B2 has been used in SU 1805097 dated 6 Dec. 1991, the applicant is Ufa Petroleum Institute.

(13) “The strain of bacteria Rhodococcus erythropolis used for purification of water and soil from petroleum and petroleum products” is included in the following categories Rhodococcus erythropolis M 2 VKM AS1339D, stays active in the soil as well. The research has revealed biodegradation of petroleum. 40 days later the biodegradation of petroleum and petroleum products after cultivation was 76%. During control, natural petroleum loss was 0.01 g. The amount of petroleum and petroleum products decreased from 3% to 1%, and 60 days later it decreased to 0.21%.

(14) Remediation of infected lands is carried out in two steps.

(15) In the first step, slit-like or round holes are made in the infected area to a depth of 25 cm of the infected soil with soluble fluorine salts exceeding the MPC by 1.5-5.0 or more times, it is poured with water, which penetrates through the holes or slits made throughout the whole volume of soil. Afterwards, 5-6 hours later, this area is poured with a bioreagent in an amount of up to 400 g per kg of soil. In this case, the interaction of soluble fluorine salts with humic acids into insoluble complexes occurs. Afterwards, the infected area of land is poured with water, and 8-10 days later the infection degree of the soil is examined prior to the second step of decontamination. Afterwards, half the initial dose of the concentrate of the humus-containing suspension is introduced, which consists of the following strains:

(16) Acinetobacter calcoaceticus VKPM-4883, Pseudomonas denitrificans VKPM 4884, Pseudomonas sp. “longa” VKPM-4885, and Rhodococcus erythropolis in an amount of (6-8).Math.10.sup.9 (3-4).Math.10.sup.9, (1.5-2).Math.10.sup.9 (1-1.5).Math.10.sup.9, (0.5-1.5) 10.sup.9 cells per 1 L of solution, respectively, in the ratio of 4.8:2.4:1.7:1.0. The bulk of soluble fluorine salts interacted with water-soluble humic acids, the amount of which decreased due to the creation of insoluble complexes of the bulk of soluble fluorine salts and due to the binding of salts of heavy metals and other contaminants, and a portion of soluble humic acids will leak into the underlying beds, failing to bind soluble fluorine salts in due time.

(17) After introduction of the second reduced dose of the humus-containing suspension, continuous water pouring is continued for 14-16 days until the content of the soluble fluorine salts in the soil amounts to the MPC of 10 mg/kg of soil and until the content of fluorine salts amounts to no more than 10-15 mg per kg of soil.

(18) The distance between the slit-like or round holes is 8-10 cm. This is justified by the fact that, depending on the composition of the soil, the penetration of the bioreagent varies, and empirical studies have shown that 4-5 cm horizontally is optimal.

(19) The results and doses of introduction of the bioreagent are summarized in the table.

(20) TABLE-US-00001 TABLE Relationship between the content of water-soluble fluorine salts and dose of introduction of a bioreagent Introduction of a Dose of introduction of the humus- bioreagent to a containing suspension, g/kg of soil depth of, cm Steps 0 200 400 25 1 48 34 24 2 — 9 —

(21) The proposed method for remediation of contaminated lands provides for treatment efficiency and a reduction in the degree of decontamination from a high degree of contamination to the MPC (maximum permissible concentration) level as well as preservation of soil biocenosis and restoration of soil fertility.