RU2753423C1 - Technology for producing a universal recultivant - Google Patents

Abstract

FIELD: building.

SUBSTANCE: invention relates to building and mining, as well as to the field of waste management, and can be used at the technical stage of reclamation of disturbed lands, including borrow excavations. The method includes production of a crushed stone and sand mixture by crushing waste to produce a crushed stone and sand mixture; production of artificial crushed stone from a mixture of ash, crushed stone, sand and cement waste in a mixing unit, followed by directing the resulting concrete mixture to the block production section for hardening, then the blocks are sent to the crushing section to produce artificial crushed stone; production of artificial soil, includinf the stages of: preparing a compost mixture from household waste and mixed waste water, wood waste and limestone dust, producing artificial soil from matured compost mixture, soil formed during excavation works and sand, then universal recultivant is produced by transporting the components of the universal recultivant to the recultivation area, forming technological tiers consisting of four layers laid alternately in the following sequence: 1) a layer of the crushed stone and sand mixture 30 to 45% vol., 2) a layer of artificial crushed stone 5 to 10% vol., 3) a layer of artificial soil 45 to 50% vol., 4) a reinforcing layer of wood waste 5 to 10% vol.

EFFECT: effective utilisation of waste of class 4 to 5 of "environmental hazard" to produce a (universal) recultivant while simultaneously reducing the environmental impact.

1 cl, 7 tbl, 1 dwg

Description

The invention relates to construction and mining, as well as to the field of waste management and can be used at the technical stage of reclamation of disturbed lands, including quarry excavations.

The closest technical solution is "Method for restoring disturbed land plots using soil for reclamation", disclosed in patent RU2654074 C1, published on May 16, 2018. The method includes backfilling of the worked-out space, its leveling and laying of the soil layer. In this case, soil for reclamation is obtained from construction and demolition waste processed at a crushing plant to the state of crushed stone-sand mixture, wood waste and soil formed during excavation work, not contaminated with hazardous substances, while the disturbed land plot is divided into conditional technological production maps works with an area of 1 hectare (100 m × 100 m), the ingredients for the production of soil for reclamation are delivered to the technological map for the formation of technological tiers, including the stages: a) filling and leveling crushed stone-sand mixture, b) filling and leveling the soil formed during excavation, not contaminated with hazardous substances, c) mixing and compaction with construction equipment, d) filling and leveling a reinforcing layer of wood waste, moving to the next technological map and repeating stages a) -d), and the technological tiers are formed with a capacity of no more than 1, 5 m to reach the level the day surface, and on the final technological tier an anti-filtration layer is formed from clay soils with a slope of 2 ° to the edge parts of the reclaimed land plot and a drainage layer is poured from the soil formed during excavation work and not contaminated with hazardous substances, with a capacity of 0.3 ± 0.2 m, on top of which a fertile soil layer with a thickness of at least 0.25 ± 0.05 m is laid, after which the biological stage of reclamation is carried out. At the same time, the filling of openings is carried out with soil for recultivation, prepared from construction and demolition waste, processed at the Mobile Screen crushing plant to the state of a crushed stone-sand mixture with a predominance of a fraction with a particle size of 5-10 mm; wood waste; soil formed during excavation, not contaminated with hazardous substances, which in its physical, physicochemical, chemical properties and composition has an affinity with the earth's crust.

The disadvantages of this method is the insufficiently efficient use of waste in the production of reclaimant.

The technical problem or task to be solved is to eliminate the existing shortcomings of the closest analogue.

The technical result, which manifests itself in solving the above problem, is the effective use of waste of 4-5 class "hazard to the environment" to obtain a universal recultivator with a simultaneous reduction in the impact on the environment.

The technical result is achieved through the implementation of a method for obtaining a universal reclaimant, including:

- production of crushed stone-sand mixture by crushing waste for the production of crushed stone-sand mixture,

- production of artificial crushed stone from a mixture of waste ash, crushed stone, sand and cement in a mixing plant, after which the finished concrete mixture is sent to the block manufacturing site, where they solidify, then the blocks are sent to the crushing site to obtain artificial crushed stone,

- production of artificial soil, including the stages:

preparation of a compost mixture from household waste and mixed wastewater - sludge, wood waste - sawdust, wood chips, shavings, and limestone flour,

preparation of artificial soil from the matured compost mixture, soil formed during excavation, and sand, then the universal recultivator is obtained by transporting the components of the universal recultivator to the reclamation zone with the formation of technological tiers, consisting of four layers, which are laid alternately in the following sequence:

1) layer - crushed stone-sand mixture 30-45% vol.,

2) a layer of artificial crushed stone 5-10% vol.,

3) layer - artificial soil 45-50% vol.,

4) reinforcing layer of wood waste 5-10% vol ..

The method of obtaining a universal recultivator includes the production of crushed stone-sand mixture (Component 1) by crushing waste for the production of crushed stone-sand mixture on a mobile crushing plant of the Terex Pegson Premier Trak 1180 type or similar on a separate site within the boundaries of the disturbed land plot to be reclaimed. Waste goes to the crushing plant directly from vehicles (the crushing product also enters the body of another vehicle standing at the output belt of the crushing plant). From the crushing plant, the crushed stone-sand mixture is transported by dump trucks to the site for the production of soil for reclamation (quarrying).

The production of artificial crushed stone (Component 2) is carried out from ash waste mixed with crushed stone (uncontaminated, substandard crushed stone waste), sand (uncontaminated sand waste) and cement is produced on a standard factory-made batching plant. The cement is delivered by cement trucks and unloaded into the cement storage silo. The volume of the silo is regulated by the schedule for the production of reclamation works and the volume of the reclaimed space. Waste ash is delivered by road transport both in bulk and in bags of the "Big-Bag" type, and is unloaded into a designated place with a hard surface, with a vertical shelter on 4 sides, preventing ash from being carried away by the wind. Sand and crushed stone are stored in bulk, in bulk. Requirements for moisture content and size of sand and crushed stone are not imposed. The loading bins of the batching plant are loaded using a front-end loader, the cement is supplied from the storage silo. The ready-mixed concrete goes to the block manufacturing site, where they harden within 3-14 days. After that, the blocks go to the crushing site to obtain artificial crushed stone. Waste goes to the crushing plant directly from vehicles (the crushing product also enters the body of another vehicle standing at the output belt of the crushing plant). From the crushing plant, crushed stone is transported by dump trucks to the site of its use for the production of soil for reclamation.

The production of artificial soil (Component 3) requires a separate production site, divided into parts:

- site for receiving and temporary storage of initial ingredients;

- a platform for composting the compost mixture;

- site for the preparation of artificial soil;

As part of the technological process, the following operations (stages) for the processing and disposal of waste are carried out:

Stage I. Preparation of the compost mixture.

Waste from the processing of domestic and mixed wastewater (sludge) must first undergo composting, which ensures their stability and decontamination.

Raw materials (waste from the processing of domestic and mixed wastewater (sludge); wood waste (sawdust, wood chips, shavings); limestone flour), waste from rainwater (storm) sewage treatment, waste from the intake and mechanical treatment of natural water , received in the form of a bulk mass, is placed at the reception and temporary storage site with a base of reinforced concrete slabs and covered with awnings to protect against rainwater and prevent dusting. Limestone flour is stored in the premises of a container block for household purposes. Each batch of sludge undergoes incoming moisture control with a Wile 65 moisture meter to clarify the required amount of introduced wood waste (sawdust, wood chips, shavings) to create a compost mass with a moisture content of no more than 65%.

In accordance with the recipe (Table 1), the ingredients of the compost mixture are transferred by a loader from the receiving and temporary storage area to the area for preliminary mixing of the compost mixture. Content of ingredients for the preparation of an intermediate product - artificial soil:

Table 1.

No.
p / p Name of ingredients Content in the product
(volume fractions) 1 Waste soil during earthworks not less than 45
and no more than 55 2 Sand - depending on moisture
(determined by the technologist) not less than 5
and no more than 15 3 Compost mix, including: not less than 15
and no more than 25 4 Waste from the processing of domestic and mixed wastewater not less than 8
and no more than 12 5 Waste sawing and planing wood - depending on humidity (determined by the technologist) not less than 6
and no more than 8 6 Limestone flour not less than 8
and no more than 10

On the composting site, using the layer-by-layer or focal method of stacking the components, they are mixed with a bulldozer in the following sequence: the prepared volume of sawdust (or chips) is leveled with a bulldozer to a layer thickness of 0.2 m. so that each subsequent layer in length and width is less than the previous one. Further, the bulldozer mixes the layers together, forming a separate volume of compost mass.

The prepared volume of compost mass is moved by a loader to form a pile, the build-up of which is made along its length. Further, the process of preparing the compost mixture and the formation of a separate pile is repeated until the end of the amount of the original raw materials received in the volume of one batch. The height of the formed pile above the ground is 2.0 m, the width is 3.0 m, and the length is not more than 200 m.

The pile formed during the period of positive ambient temperatures is covered with a protective film to improve the regulation of the moisture content - it is possible to use a black polyethylene film for silage trenches with a thickness of 120 microns.

Before the beginning of the winter period, to maintain microbiological processes inside the pile and protect it from freezing, the pile surface is covered with a layer of clay 0.5 m thick.

Carrying out daily monitoring of the biomass temperature at the midpoint of the pile using an external temperature probe Wile 651L.

Between positive ambient temperatures biomass after reaching the temperature at the midpoint of collar 30-35 ^{° C} (approximately 5-10 hours) start to move (pereburtovaniyu) compost mass in order to improve aeration, additional moistening, composted mass homogenization to prevent phase separation ingredients and stop the fermentation process. The action is carried out by moving the mass of the pile to a free adjacent section of the compost mixture lumping area so that the compost from the outer part of the pile moves inward, and from the inner part to the outside. The process is carried out using an excavator bucket or a removable mounted screening bucket-crusher. Each transfer must be completed within one working day. Further, pereburtovanie is performed 1 time in 5 days for 30-90 days until visual signs of compost readiness are achieved - a crumbly, homogeneous mass, smelling of earth.

Technological conditions:

The fermentation process is considered active if within 14 days from the date of formation of the pile the temperature of the biomass at the midpoint of the pile is 30–35 ^о С, and on 20–30 days it will be 45–60 ^о С, after which all actions with the pile stop and occurs cooling of the soil to 20–30 ° С. The holding time of the biomass in the pile is from 30 to 90 days. The compost is considered ready-to-use to obtain an intermediate product - artificial soil.

Intermediate quality control of the resulting compost mixture for compliance with the requirements of sanitary-microbiological and sanitary-parasitological indicators. In case of non-compliance of the compost mixture with the requirements of sanitary and microbiological indicators, the composting time of the mixture is lengthened, repeated wrapping and repeated quality control are carried out.

Stage II. Artificial soil preparation.

The ripened compost mixture from the pile-up site is transferred by a loader or dump trailer to the artificial soil preparation site, where the soil formed during excavation and sand from the temporary storage site of raw materials are delivered.

Pre-mixing with a bulldozer of soil formed during excavation; sand and compost mixture in quantities according to Table 1. Final mixing with a removable attachment bucket with mixing function.

Then, to obtain a universal reclamation agent, these components are moved to the reclamation zone using road transport with the formation of technological tiers in the following sequence:

1) layer Component 1 - crushed stone-sand mixture 30-45% vol.,

2) layer Component 2 - artificial crushed stone 5-10% vol.,

3) layer Component 3 - artificial soil 45-50% vol.,

4) reinforcing layer Component 4 wood waste 5-10% vol ..

For the production of a universal Recultivant, a system of differentiating the worked-out space of disturbed land plots into planar and volumetric structural elements is used, which is the basis for improving the reclamation technology: Technological tiers of "Rekultivant" with a thickness of 1.5 m are formed on each map.

Delivery of ingredients for the production of Universal Recultivant is carried out by any means of transport, in accordance with the rules for the carriage of goods in force on transport.

Unloading of ingredients for the preparation of a universal Recultivant directly at the reclamation site (on the map subject to priority reclamation).

Reclamation of a quarry is carried out by technological tiers, the capacity of which does not exceed 1.5 m. The schematic diagram of the formation of a technological tier is a layer-by-layer linear filling of the components of a universal recultivator with intermediate leveling with special equipment (a B10M bulldozer or similar, or a motor grader) and, if necessary, final compaction vibratory rollers. The bulldozer penetrations are carried out by straight, oblique parallel, oblique cross or combined passes, which leads to additional mixing of the crushed waste to obtain a homogeneous soil-like mixture of a loose consistency.

Each technological level consists of four layers. The filling of the components is carried out alternately in the following sequence:

- layer of Component 1 - crushed stone-sand mixture with a thickness of 0.7 m;

- leveling;

- layer of Component 2 - artificial crushed stone 0.2 m

- leveling;

- layer of Component 3 - artificial soil with a thickness of 0.3 m;

- leveling;

- the reinforcing layer of Component 4 of wood waste with a thickness of 0.3 m;

- the final seal.

The formation of the technological tier of the Universal Recultivant is shown in Fig. 1.

Thus, the proposed technology for obtaining a universal Recultivant assumes the utilization of waste of 4-5 classes of hazard for the environment ”and consists in laying in layers of four components.

As Component 1, in particular, they use waste from stripping operations in the extraction of minerals, Waste from the production of other non-metallic mineral products, similar to utilities in production, waste from the provision of services to the public (KGM), Other waste from the preparation of the construction site, Waste from the production of construction ceramic materials, Waste from the production of products from asbestos cement and fiber cement, Waste glass and glass products, uncontaminated, Waste of thermal insulation materials based on mineral fibers , Waste of ceramic products, Waste from demolition and dismantling of buildings, Waste of refractory materials from the repair of furnaces and furnace equipment, Waste of building materials based on natural stone, Waste of soils of hazard classes 4 and 5, Waste of construction materials materials based on cement, concrete and mortars, Waste of ceramic building materials, Waste of building materials based on mineral binders, Waste during dismantling, repair of road surfaces, Waste ballast when cleaning railway tracks, Other waste from construction and repair of buildings, structures, Waste ( residues) of sand and gravel mixture during construction, repair work, Waste from maintenance and repair of furnaces and furnace equipment processed on a mobile crushing plant such as "Terex Pegson Premier Trak 1180" or similar to the state of crushed stone-sand mixture;

As Component 2, artificial crushed stone from waste is used, in particular: Ashes, slags and ash-and-slag mixtures from solid fuel combustion, Wastes from thermal neutralization of municipal and mixed wastewater sludge, Wastes from the incineration of municipal solid waste, industrial consumption waste, such municipal waste, Waste from the neutralization of medical waste, Waste from the neutralization of other types and groups of waste, Waste from processing, utilization, disposal of sewage sludge, Waste sand uncontaminated, Waste of construction crushed stone, uncontaminated, Limestone crushed stone, dolomite substandard practically non-hazardous, processed on a standard batch plant execution with the receipt of intermediate blocks and further processed on a mobile crushing plant such as "Terex Pegson Premier Trak 1180" or similar to the state of crushed stone. (In the absence of components for the manufacture of artificial crushed stone from waste of the 4th and 5th hazard classes, it is allowed to replace it with: uncontaminated construction crushed stone, limestone crushed stone, dolomite substandard practically non-hazardous, crushed stone-sand mixture from 4th and 5th waste th hazard classes; soil waste during earthworks).

As Component 3, artificial soil from waste is used, in particular: Soil waste, Uncontaminated sand waste, Compost mixture from Waste (sludge) during mechanical and biological treatment of household and mixed waste water in a mixture processed according to technological regulations, Waste (sludge ) during mechanical and physical and chemical treatment of domestic and mixed wastewater, Waste from rainwater (storm) sewage treatment, Waste from the intake and mechanical treatment of natural water, Wood sawdust (chips, shavings), Limestone flour. In the absence of components for the manufacture of artificial soil from waste of the 4th and 5th hazard classes; it is allowed to replace it with: soil waste during earthworks.

As Component 4, wood waste is used, in particular: Waste from forestry and logging, Waste from wood processing and production of wood products, Wood products that have lost their consumer properties.

As a result, an environmentally friendly product is formed - a universal Recultivant, the production process and the use of which do not lead to a negative impact on the components of the natural environment. The developed technology will allow restoring the relief surface and individual components of the natural environment of the disturbed land plot to its original state for the purposes of agricultural, forestry, environmental, sanitary and hygienic areas of their reclamation in accordance with GOST 17.5.1.02-85 "Classification of disturbed lands for reclamation" GOST 17.5.3.04- 83 "General requirements for land reclamation" and GOST R 54534-2011 "Resource conservation. Sewage sludge. Requirements for use for reclamation of disturbed lands ”.

The production of a universal recultivator using the above technology with the disposal of waste of 4-5 class of hazard for the environment ”is carried out directly in the quarries of the disturbed land plot at the technical stage of reclamation.

The choice of waste types for disposal for reclamation of disturbed lands (quarries) was justified by the following criteria:

1) ecological and hygienic - the admissibility of disposal from the point of view of safety for people and the environment;

2) resource - the presence of a sufficient amount of waste for the organization of production;

3) the migration ability of waste components - the absence of migration of pollutants hazardous to the components of the natural environment.

The wastes selected for disposal in terms of their properties and selected ratios correspond to the above requirements, which is justified by the results of scientific research given below in the "Approbation".

When deciding on the ratio of the mixed ingredients (waste), the environmental safety and mechanical stability of the resulting universal Recultivant were taken into account.

To test the claimed method, a production site was chosen, on which 3 batches of universal Recultivant were prepared at different times. Mixed samples were taken from the volume of a separate batch of a universal Recultivant, sufficient for reclamation of a land plot with a layer thickness of 1.5 m.

The test results of the universal recultivator, produced in the course of approbation of the "technology for obtaining a universal recultivator with the disposal of waste of 4-5 class of hazard for the environment" in accordance with the controlled indicators are given in Table 2.

Table 2. Results of the study "Recultivant universal"

Gross forms of heavy metals, mg / kg Sample from 08/14/2017 Sample from 08/31/2017 Sample from 09/13/2017 The most stringent standard value of the indicator pH of the aqueous extract, units NS 7.2 6.8 6,7 5-7 Cadmium Cd 0.8 0.5 0.5 2 Lead Pb 41.4 36.4 12.9 130 Chromium Cr 9.9 36.5 12.3 1000 Zinc Zn 31.1 41.2 33,7 220 Copper Cu 29.1 32.0 23.9 132 Nickel Ni 34.5 12.2 18.1 80 Mercury Hg <0.005 <0.005 <0.005 2 Arsenic As <0.2 <0.2 <0.2 ten Petroleum products 52.1 42.6 41.1 1000 COD 230.0 185.0 129.0 700 BOD5 210.0 265.0 305.0 500

The results of the analysis of the samples of "Recultivant universal" showed that the content of the bulk forms of controlled heavy metals meets the requirements of GN 2.1.7.2041-06 and GN 2.1.7.2511-09.

Additionally, studies were carried out on Component 3 and crushed stone-sand mixture (mixture of Components 1 and 2). The results of tests carried out in the course of approbation of the new technology are shown in table. 3 and tab. 4. in accordance with test reports No. 517 dated 15.08.2017, No. 587 dated 18.09.2017, No. 515 dated 07.08.2017, No. 568 dated 03.09.2017.

Table 3. Results of the study of Component 3 “Universal recultivator”.

Gross forms of heavy metals, mg / kg Component sample from 04/08/2017 Component sample from 09/07/2017 pH of the aqueous extract, units NS 6,7 6.4 Cadmium Cd 0.3 0,4 Lead Pb 11.4 11.9 Chromium Cr 11.5 12.5 Zinc Zn 31.1 29.9 Copper Cu 22.0 23.1 Nickel Ni 32.2 31.4 Mercury Hg <0.005 <0.005 Arsenic As <0.2 <0.2 Petroleum products 32.6 42.9

Results of the study of the mixture of Components 1 and 2 of the "Universal Recultivant".

Table 4

Gross forms of heavy metals, mg / kg Component sample from 07/28/2017 Component sample from 08/02/2017 pH of the aqueous extract, units NS 7.1 6,7 Density, t / m3 2.4 2.45 Lead Pb 3.3 2,3 Zinc Zn 19.1 19.6 Copper Cu 3.1 2.1 Nickel Ni 3.7 2.7

The results of the radiological examination of the "Universal Recultivant" showed that the content of individual radionuclides: cesium-137, potassium-40, radium-226 and thorium-232 is below the permissible levels (Table 5).

Table 5

Results of radiological tests "Universal recultivant"

Specific activity, Bq / kg Sample from 08/14/2017 Sample from 08/31/2017 Sample from 09/13/2017 UEC Cs-137 Less than 2.8 Less than 2.4 Less than 2.8 100 K-40 78 ± 33 86 ± 33 75 ± 40 - Ra-226 10.2 ± 5.3 8.4 ± 4.8 12.4 ± 6.2 - Th-232 8.6 ± 2.3 8.3 ± 5.2 10.3 ± 1.8 - A eff 30.2 ± 7.8 27.0 ± 4.0 31.3 ± 8.2 370

Additionally, radiological studies of Components 1,2,3 of the "Universal Recultivant" were carried out (Table 6,7).

Table 6

Results of radiological tests of Components 1 and 2 in a mixture of "Recultivant universal"

Specific activity, Bq / kg Component sample from 07/28/2017 Component sample from 08/02/2017 UEC Cs-137 Less than 6.8 Less than 1.6 100 K-40 142 ± 70 135 ± 38 - Ra-226 8.2 ± 4.3 12.3 ± 6.8 - Th-232 12.6 ± 6.2 10.4 ± 7.3 - A eff 37.3 ± 2.4 37.9 ± 4.8 370

Table 7

Results of radiological tests of Component 3 "Universal Recultivant"

Specific activity, Bq / kg Component sample from 04/08/2017 Component sample from 09/07/2017 Component sample from 08/25/2017 UEC Cs-137 Less than 2.8 Less than 2.2 Less than 2.6 100 K-40 121 ± 35 130 ± 33 62 ± 38 - Ra-226 8.4 ± 2.3 10.3 ± 4.8 10.3 ± 3.7 - Th-232 15.0 ± 7.2 15.3 ± 8.3 12.6 ± 6.4 - A eff 38.7 ± 7.2 41.9 ± 6.8 26.4 ± 8.3 370

Consequently, the resulting "Universal Recultivant" is characterized as not contaminated with radionuclides.

The claimed method makes it possible to produce a universal recultivator that allows restoring the relief surface and individual components of the natural environment of the disturbed land plot to its original state for the purposes of agricultural, forestry, environmental protection and sanitary-hygienic directions of their reclamation using waste.

The proposed technical solution ensures the involvement of various wastes in secondary production: construction waste, in particular for the production of crushed stone-sand mixture, ash waste mixed with crushed stone (waste of uncontaminated crushed stone, substandard), waste of uncontaminated sand, wood waste; artificial soil from wastes obtained during the processing of domestic and mixed wastewater (sludge); wood waste (sawdust, wood chips, shavings); limestone flour, waste from rainwater (stormwater) sewage treatment, waste from the intake and mechanical treatment of natural water, which allows not only to restore the surface of the relief, soil and vegetation cover disturbed by quarry excavations of land, but also to prevent erosion processes while reducing the impact on the environment.

Claims (11)

A method of obtaining a universal reclamation agent, including: - production of crushed stone-sand mixture by crushing waste for the production of crushed stone-sand mixture, - production of artificial crushed stone from a mixture of waste ash, crushed stone, sand and cement in a mixing plant, after which the finished concrete mixture is sent to the block manufacturing site, where they solidify, then the blocks are sent to the crushing site to obtain artificial crushed stone, - production of artificial soil, including the stages: preparation of a compost mixture from household waste and mixed wastewater - sludge, wood waste - sawdust, wood chips, shavings, and limestone flour, preparation of artificial soil from matured compost mixture, soil formed during earthworks, and sand, then the universal recultivator is obtained by transporting the components of the universal recultivator to the reclamation zone with the formation of technological layers, consisting of four layers, which are laid alternately in the following sequence: 1) a layer of crushed stone-sand mixture 30-45% vol., 2) a layer of artificial gravel 5-10% vol., 3) a layer of artificial soil 45-50% vol., 4) the reinforcing layer of wood waste 5-10% vol.

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