RU2797056C1 - Method for intensifying the reclamation succession of lands contaminated with heavy metals - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: invention relates to a method for intensifying the reclamation succession of lands contaminated with heavy metals by introducing an organo-mineral substrate into them, consisting of frozen lignin-containing residues of the pulp and paper industry (sludge-lignin) and ashes from burning wood fuel. The method includes introducing an organo-mineral substrate into disturbed lands contaminated with heavy metals, consisting of frozen sediments of lignin sludge and wood fuel combustion ash, to intensify reclamation succession by introducing optimal amounts of plant nutrients (organic matter, potassium, phosphorus, nitrogen) and immobilization of heavy metals. The method is carried out by adding an additive, which is wood fuel combustion ash, to the frozen sediments of lignin sludge in a ratio of 1:0.05, followed by mixing and adding 30 t/ha to disturbed lands contaminated with heavy metals to intensify reclamation succession.

EFFECT: intensified processes of reclamation succession of disturbed lands contaminated with heavy metals.

1 cl, 3 tbl

Description

The invention relates to a method for intensifying the reclamation succession of lands contaminated with heavy metals by introducing into them an organo-mineral substrate consisting of frozen lignin-containing residues of the pulp and paper industry (sludge-lignin) and wood fuel combustion ash.

The invention relates to critical technologies for Russia "Technologies for monitoring and predicting the state of the environment, preventing and eliminating its pollution" and to the priority direction of development of science and technology "Rational nature management" (approved on 07.07.2011), since it includes the technology of intensification of reclamation succession of disturbed lands and the use of production waste - lignin-containing residues from the pulp and paper industry and the ashes of burning wood fuel.

The most difficult problem hindering the reclamation of lands disturbed during the activities of various industrial enterprises is their pollution with heavy metals.

There are the following main directions for solving this problem:

- carrying out phytorecultivation;

- removal and disposal of contaminated soil at landfills;

- application of physical and chemical methods of reclamation (chemical extraction, pyrometallurgical and electrochemical processing, vitrification) with the extraction of contaminated soil.

However, the above methods of reclamation of disturbed lands have a number of significant drawbacks that reduce their efficiency and profitability, for example:

- high content of heavy metals negatively affects the growth and development of plants used for phytoremediation, their significant accumulation in plant biomass creates a problem of its utilization;

- removal of contaminated land for disposal at special landfills from a technical and economic point of view is highly costly and not always appropriate, while due to their high hazard class, certain restrictions are imposed on removal and storage;

- physical and chemical methods of processing heavily polluted lands are also costly, they require specialized equipment and chemicals capable of secondary pollution of environmental objects.

The prior art method of introducing an organomineral additive into the soil (RU No. 2723401, IPC C05B 17/00, C05F 7/02, A01B 79/02, published on 06/11/2020). The invention relates to the field of agriculture and can be used as a long-acting organomineral supplement for the purpose of cultivating forest areas, reclamation of highway slopes and municipal solid waste dumps.

The essence of this invention lies in the fact that the organomineral additive is applied at a ratio of organomineral additive and soil 1:1, then dispersion and plowing are carried out, while phosphogypsum is used as the mineral component of the additive, lignin sludge is used as the organic component, and the components are used in the following the ratio of components by weight (wt.%): phosphogypsum - 20-25, lignin sludge - 75-80. The disadvantage of this method is its technical and economic costs (the ratio of additives and soil is 1:1) and the fact that this method is only suitable for lands containing low concentrations of heavy metals (cultivation of forest areas, reclamation of slopes of roads and landfills of municipal solid waste, at the same time, it contributes to the transition of heavy metals and rare-earth metals into plants, which is not suitable for the reclamation of lands disturbed during the activities of industrial enterprises

Common features of the claimed invention with analogue is the improvement of the agrochemical properties of soils by adding additives, as well as the use of lignin-containing residues of the pulp and paper industry - sulfite sludge-lignin as an organic component.

Also known is a method for producing organomineral fertilizer (RU No. 2086521, IPC C05F, published on 08/10/1997), the essence of which lies in the fact that the mineral base, which is taken as brown coal ash, is filled with industrial and agricultural waste, such as sludge - lignin, activated sludge from pulp and paper mills, wood waste. Cattle manure or bird droppings are added to the mixture in an amount of not more than 1/3 of the total mass of the components and composting is carried out. The mass ratio of ash to the rest of the waste is 1:1.5-5.

The disadvantage of this method is the limitation of its use associated with the use of cattle manure or bird droppings, as well as the failure to ensure the full microbiological purity of the fertilizer. At the same time, the need for composting the mixture increases the complexity of the technology and increases technical and economic costs.

Common features of the claimed invention with analogue are the possibility of obtaining soil-fertilizing material, the possibility of processing waste from the pulp and paper industry, as well as the use of sulfate sludge-lignin as an organic component for obtaining raw materials.

There is also a known method for processing lignin sludge into biofertilizer (Application RU No. 2019114539, IPC C05F 7/02, C05F 17/00, published on 11/13/2020), which is carried out as follows - trapezoidal-shaped collars are formed on the site, after a day, taking into account humidity 70 -80% and temperatures up to 50%, an inoculant is introduced into the collar, a biological product based on BR-1256, which, by activating the microflora of the collar, changes the biochemical composition of lignin sludge, turning it into an organic biofertilizer, while the speed of the lignin sludge processing into biofertilizer is regulated by turning collar 2-3 times a week, during which additional moisture is added or aeration is carried out.

The disadvantage of this method is that this method is technologically complex and costly (introducing up to 50% of the inoculant into the pile), since in order to obtain biofertilizer it is necessary to form special-shaped piles, while the method requires the introduction of additional moisture or aeration and temperature and humidity control. substrate.

Common features of the claimed invention with analogue are the possibility of obtaining soil-fertilizing material, the possibility of processing waste from the pulp and paper industry, as well as the use of sulfate lignin sludge as an organic component for obtaining raw materials.

For the prototype, a method was adopted for obtaining soils for the reclamation of disturbed lands (Bogdanov A.V. et al. “Pilot tests of the technology for freezing out colloidal sediments of sludge-lignin JSC “Baikal Pulp and Paper Mill”, XXI CENTURY. TECHNOSPHERE SAFETY, 2020, No. 5 (1), pp. 8-20), which consists in obtaining soils by mixing frozen lignin sludge with sewage treatment plant sludge in a ratio (4: 1) or by mixing frozen lignin sludge with sewage treatment plant sludge and ash from a thermal power plant in the ratio 4:1:1.

The disadvantages of this method are as follows:

- the use of precipitation from urban sewage treatment plants - activated sludge causes secondary microbiological contamination of the resulting mixture and may adversely affect its organoleptic characteristics;

- the use of CHP ash additionally introduces heavy metals and benzo(a)pyrene into the resulting mixture;

- this method does not regulate the amount of application of the resulting soil into disturbed lands contaminated with heavy metals for reclamation.

The difference between the proposed method and the prototype lies in the fact that the preparation of soil in the prototype is carried out by mixing the frozen sediment of sludge-lignin with sludge from sewage treatment plants in the ratio (4:1) or by mixing the frozen sediment of sludge-lignin with sludge from sewage treatment plants and ash from a thermal power plant. in a ratio of 4:1:1, while the amount of soil introduced into disturbed lands contaminated with heavy metals for reclamation is not regulated. Whereas in the proposed method, frozen lignin-containing sludge from the pulp and paper industry (sludge-lignin) and wood fuel combustion ash are mixed in a proportion of 1: 0.05, then the mixture is applied to disturbed lands contaminated with heavy metals in the amount of 30 t/ha .

The presence of distinctive features allows us to conclude that the claimed invention complies with the condition of patentability "novelty".

The task to be solved by the claimed invention is to intensify the reclamation succession of disturbed lands contaminated with heavy metals with the use of a soil-fertilizing mixture, which will allow their reclamation, increase the rate of self-overgrowth and increase the species biodiversity of phytocenoses, while solving the problem of recycling large-tonnage accumulated lignin -containing sediments of the pulp and paper industry - lignin sludge.

The technical result of the claimed invention is to intensify the processes of reclamation succession of disturbed lands contaminated with heavy metals.

The specified technical result is achieved by the fact that the method of intensifying the reclamation succession of lands contaminated with heavy metals consists in the fact that, in order to obtain an organo-mineral substrate, frozen lignin-containing sediments of the pulp and paper industry, which are lignin sludge, are mixed with wood fuel combustion ash in share ratio of 1:0.05, then the resulting mixture is applied to disturbed lands contaminated with heavy metals in the amount of 30 t/ha to intensify the processes of reclamation succession.

The advantages over the prototype are that the claimed method involves the introduction of a chemically and microbiologically safe component into the frozen sediments of lignin sludge - almost non-hazardous wood fuel ash (FKKO code: 6 11 900 02 40 5), which is rich in such components valuable for plant nutrition , as potassium and phosphorus, while this method regulates the amount of application of the resulting soil to disturbed lands contaminated with heavy metals for reclamation.

The essence of the claimed invention lies in the fact that with the proposed method of intensifying the reclamation succession of lands contaminated with heavy metals, they introduce an organo-mineral substrate in the amount of 30 t/ha, which is a mixture consisting of frozen lignin-containing sediments of the pulp and paper industry, represented by lignin sludge with wood fuel combustion ash in a share ratio of 1:0.05. At the same time, a large amount of cellulose fiber, which is part of the frozen sediments of sludge-lignin, has high sorption properties for heavy metals and allows them to be immobilized in the soil, converting them into a form inaccessible to plants. Also, the frozen sediment of sludge-lignin contains a large amount of organic substances (up to 45%) necessary for the growth and development of plants. The additive introduced into the mixture - wood fuel combustion ash is practically non-hazardous (FKKO code: 6 11 900 02 40 5) belongs to the V class of hazard (practically non-hazardous) waste, which poses the least danger to the environment and humans, has a low impact on the environment, practically without breaking its components. At the same time, this ash contains a large amount of nutrient components for the development and growth of plants - oxides of potassium, phosphorus, and due to the alkaline environment it stabilizes the frozen sediment of lignin sludge, which has a slightly acidic environment. The intensification of reclamation succession lies in the fact that the optimal amount of nutrients, as well as a decrease in the availability of heavy metals for plant assimilation, accelerates the processes of self-overgrowing of disturbed lands and a rapid change in the biological diversity of phytocenoses.

This method of intensifying the reclamation succession of lands contaminated with heavy metals is carried out as follows:

In pre-dried under natural conditions, frozen lignin-containing residues of the pulp and paper industry, which are sludge-lignin, an additive is introduced, which is an average ash from the combustion of wood fuel, practically non-hazardous (FKKO code: 6 11 900 02 40 5) in a proportion of 1: 0 .05, then the mixture is evenly mixed throughout the volume. Since the moisture content of frozen sediments of sludge-lignin is about 25-35%, additional irrigation is not required. The resulting organo-mineral substrate is introduced to intensify reclamation succession in disturbed lands contaminated with heavy metals in the amount of 30 t/ha.

To select the optimal ratios of frozen sludge-lignin sludge: wood fuel combustion ash, laboratory and pilot tests were carried out. The average composition of the frozen sediments of sludge-lignin and ash from the combustion of wood fuel in terms of the main nutrient components for plants is shown in Table 1.

Table 1 - The average composition of the frozen sediments of lignin sludge and wood fuel combustion ash in terms of the main nutrient components for plants

Component Sample Requirements of GOST R 54651-2011 “Organic fertilizers based on sewage sludge. Specifications» Frozen sediment of sludge-lignin Wood burning ash Organic matter, % 40-45 less than 5 at least 30% Phosphorus total, in terms of P ₂ O ₅ ,% 0.5-0.8 4.0-6.0 not less than 0.7 Potassium total, in terms of K ₂ O,% 0.07-0.12 10.0-12.0 not less than 0.1 Nitrogen total, % 0.9-1.5 less than 0.1 not less than 0.6

As can be seen from Table 1, the frozen sediment of lignin sludge has, first of all, a deficiency of potassium, as well as phosphorus in relation to nutrients, while total nitrogen and organic matter meet the requirements of GOST R 54651-2011 for the main nutrient components for plants. Table 1 also shows that wood fuel combustion ash is rich in such nutrients as total potassium and phosphorus, which gives prerequisites for using it as an additive to obtain an organo-mineral substrate.

Studies have been carried out to select the optimal ratios of the frozen-out sludge-lignin sludge and wood fuel combustion ash. For this, the following ratios of the frozen sludge-lignin sludge and wood fuel combustion ash were chosen: 1:0.01; 1:0.025; 1:0.05; 1:0.10; 1:0.15; 1;20, then the chemical composition of plant nutrients, the pH of the water extract, the average wet weight of the plants planted in the samples (oil radish ( Brassica rapa ) on the 14th day of germination were analyzed. The test results are presented in table 2.

Table 2 - Selection of the optimal components of the organo-mineral substrate

Component The ratio of the frozen sludge-lignin sludge: wood fuel combustion ash in shares 1:0.01 1:0.025 1:0.05 1:0.10 1:0.15 1:0.20 Organic matter, % 42.4 41.9 41.5 38.4 36.8 32.6 Phosphorus total, in terms of P ₂ O ₅ ,% 0.6 0.7 0.8 1.0 1.2 1.3 Potassium total, in terms of K ₂ O,% 0.12 0.25 0.57 1.12 1.47 1.89 Nitrogen total, % 0.94 0.86 0.81 0.78 0.75 0.71 pH of water extract 5.9 6.1 6.4 6.9 7.3 7.9 Average wet weight of plants planted in samples (oil radish (Brassica rapa) on the 14th day of germination, g 0.21 0.22 0.28 0.31 0.33 0.35

Based on the results obtained, shown in Table 2, the optimal ratio of frozen-out sludge-lignin sludge: wood fuel combustion ash was chosen to be 1:0.05, since this ratio does not significantly reduce the concentration of such nutrients as organic matter and total nitrogen and the substrate is saturated with phosphorus and potassium to the required values.

The resulting organo-mineral substrate is applied to intensify reclamation succession in disturbed lands contaminated with heavy metals in the amount of 30 t/ha, in accordance with the Requirements of GOST R 54651-2011 “Organic fertilizers based on sewage sludge. Specifications".

Comparison of the main technical characteristics of the claimed method of intensifying reclamation succession and those already known earlier is shown in Table 3.

Table 3 - Comparison of the main technical characteristics of the claimed method and previously known

Components can contaminate the environment secondarily (microbiological, chemical contamination) The need for composting / mixture stabilization Possibility of reclamation of disturbed lands contaminated with high content of heavy metals Analogue 1 (US Pat. No. 2723401) +
(heavy and rare earth metals) - -
(promotes the accumulation of heavy and rare earth metals in plants) Analogue 2 (US Pat. No. 2086521) +
(microbiological contamination - manure, droppings) +
(the need for composting) -
(there is no indication of this possibility in the method) Analogue 3 (Application No. 2019114539) - +
(requires regular aeration and moisture application) -
(there is no indication of this possibility in the method) Prototype +
(activated sludge - microbiological pollution, odor; CHP ash - benz (a) pyrene, heavy metals) ±
(the need to use spent and stabilized activated sludge from sewage treatment plants, while the mixture itself does not require stabilization) ±
(the composition indicates the possibility of use, but does not regulate the exact rate of application to disturbed lands) Suggested method - - +

As can be seen from table 3, unlike the prototype, the proposed method allows to intensify the reclamation succession of disturbed lands contaminated with heavy metals without the introduction of components that can re-contaminate the environment and must be pre-stabilized, while this method regulates the application rates of the organo-mineral substrate into disturbed lands.

Unlike analogues, the proposed method allows not to use components that can pollute the environment again, does not require composting and stabilization of the resulting mixture, and allows intensifying the reclamation succession of disturbed lands contaminated with a high content of heavy metals.

The use of the claimed invention will make it possible to utilize large-tonnage lignin-containing sediments of the pulp and paper industry, represented by frozen sediments of sludge-lignin, to obtain valuable commercial products - an organo-mineral substrate that can be used for reclamation of disturbed lands without high technical and economic costs for its production.

Claims (1)

A method for intensifying the reclamation succession of lands contaminated with heavy metals by introducing an organo-mineral substrate into them, characterized in that the method is carried out by introducing into the frozen lignin-containing sediments of the pulp and paper industry (lignin sludge) an additive, which is wood fuel combustion ash , in a share ratio of 1:0.05, followed by mixing and application to intensify reclamation succession in disturbed lands contaminated with heavy metals, in the amount of 30 t/ha.