RU2389563C2 - Environment and method on waste treatment in mining - Google Patents

Abstract

FIELD: process engineering. ^ SUBSTANCE: invention relates to treatment of wastes, ore and minerals concentration. Treatment of waste bank formed in mining operations comprises introducing wood chips produced from wastes of wood from mine wood balks destructed in blasting jobs, i.e. bypass product, into said waste balk and processing said balk by wood chips till the level of 30 cm below outer surface. Waste balk treatment can comprise enrichment with compost using earthworms, mixes of wood particles and effluents, introducing obtained mix into waste balk and planting on waste balk. ^ EFFECT: application of cheap and available materials, improved ecology. ^ 20 cl, 17 tbl, 9 dwg, 5 ex

Description

FIELD OF THE INVENTION

The present invention relates to a medium and method for treating waste generated during mining.

State of the art

As a result of human activity, for example, during mining, a large amount of waste is generated, which creates economic problems and environmental protection problems. This is due to the need to use large areas of land for waste disposal, which leads not only to significant costs, but also to pollution of soil, groundwater and air. In particular, the extraction of platinum, gold and other minerals has a significant impact on the environment due to the formation of significant tailing dumps. Tailings dumps are formed from sludge streams - flotation waste generated during the processing of minerals, and are essentially a biologically sterile environment with limited water retention capacity and a high percentage of basic saturation. Dumps also have, among other things, high concentrations of potentially toxic heavy metals that can be released into groundwater.

Studies conducted by Walmsley (1987) showed that although the dumps are not saline, they contain large amounts of manganese, iron, and sulfur, which can be phytotoxic at high concentrations. Dumps in platinum mining, for example, are mainly composed of sand (75%) and sediment (20%), while the remaining 5% of the particles are clay and an insignificant organic fraction. The above factors, for this reason, make it difficult to restore vegetation on dumps to the potential level that this land had before mining began, which leads to environmental pollution in the area. In addition to inorganic waste, platinum mining also generates large amounts of organic waste, namely wood chips from Saligna eucalyptus wood, as well as sewage sludge. Landfills form a whole range of environmental hazards, including air pollution, dust and groundwater pollution, due to the physical and chemical properties of the heaps, while wood chip waste poses a fire hazard in the hot and dry summer months.

Wood chips are formed during the extraction of platinum as a result of underground blasting, when wooden buttresses are left in the mine. As a result, wood chips and ore are jointly processed during the initial grinding and extraction phases (stages) during mineral processing. The wood chips fraction is separated as a by-product using a screening method before platinum extraction. As a result of explosions, wood chips have (acquires) a high concentration of nitrates, which is high enough to create problems for human health, leading to methemoglobinemia if they are leached into groundwater (DWAF, 1996). Currently, wood chips are burned out, which leads to a significant increase in operating costs.

Thus, the formation of sludge, wood chips and wastewater is a problem associated with the need to take special measures to protect the environment.

The main objective of the landfill restoration projects is to return the contaminated site to the conditions it was in before the contamination, which often involves restoring vegetation to stabilize the cultivated soil. This process is both time consuming and expensive due to the lack of a potentially fertile topsoil, as well as due to a deficiency of organic matter, an imbalance of elements and the lack of sufficient nutrients in tailing dumps. When trying to solve these problems, the topsoil is imported from other areas (in which soil restoration is then required) or periodically treated with inorganic fertilizers, which are both expensive and do not provide a sustainable environmental impact. Most tailing dumps are currently being restored by growing grass dumps. The development of a viable and sustainable vegetation cover, however, presents a problem due to infertility and phytotoxicity of the vegetation growth environment.

In US patent No. 6004069 describes a method of forming a subaerial inorganic composite coating on the surface of dumps, the material of which contains sulfides and mining waste containing sulfides, comprising the following steps:

i) the formation of a dump from a material in the form of solid sulfide particles, including at least one of the group, dumps containing a sulfide mineral, waste rock containing sulfides, and mining waste materials containing sulfides, said material being in the form of solid sulfide particles has low hydraulic conductivity, the specified blade contains a peak and slope at an angle of more than 0.5 degrees with respect to the horizontal;

ii) applying a first layer of particles on top of the specified solid sulfide particle material blade, wherein said first layer of particles contains an inert finely ground substance with an average particle size of 10 μm and 200 μm and a hydraulic conductivity of more than 10 ⁻⁷ cm / s, the matrix suction value more than 4 cm of water, and the specified first layer of particles is applied so as to obtain the specified first layer of particles located on the surface of the specified dump sulfide material in depth greater than 4 cm;

iii) applying a second layer of particles on top of the specified blade material sulfide particles, and the specified second layer of particles contains an inert substance in the form of small granules with an average particle size of from 200 microns to 5000 microns, hydraulic conductivity from 10 ^-3 to 1 cm / s, and hydraulic the conductivity of said second layer of particles is at least an order of magnitude higher than the hydraulic conductivity of said first layer of particles, and as regards the absorption value of the matrix, the ratio of the absorption value of the matrix of said second layer is stits to the absorption value of the matrix of the specified first layer of particles is less than 1: 2, the specified second layer of particles is applied so that it is located on top of the specified first layer of particles and has a depth of at least 1.5 times greater than the absorption value matrices, measured in centimeters of a layer of water, said second layer of particles; and

iv) applying a third layer of particles on top of the specified sulphide particle material blade, said third layer of particles containing an inert substance with large granules, the average size of which is more than 3 mm, and having a hydraulic conductivity value greater than 1 cm / s, wherein said third layer of particles is applied on top of the specified second layer of particles with a depth exceeding 6 cm

The inert, finely ground material of which the first layer of particles is composed is selected from the group consisting of waste from oxidizing plants, waste from processing plants with a low sulfide content, desulfurized waste from processing plants, neutralized waste from processing plants, loess, fine sand, sand clay, sandy loam, fly ash, sedimentary rocks, glacial boulder clay, finely ground alluvial materials and mixtures thereof.

The inert substance in the form of fine granules, of which the second layer of particles consists, is selected from the group consisting of granulated slag, granular desulfurized slag, desulfurized gangue, fine gravel, finely ground gangue, sand and a mixture thereof.

The inert substance in the form of large granules, from which the specified third layer of particles consists, is selected from the group consisting of crushed gangue, crushed stone, crushed limestone, pebbles and coarse materials of natural origin, crushed materials resulting from blasting, and mixtures thereof.

Some of the disadvantages of the above method are that organic matter is not added to the upper layers, and that this method is a relatively complex and expensive process involving the use of many different substances and steps. Thus, this method is commercially unacceptable.

Disclosure of invention

Thus, the present invention is directed to an environment and a method for treating waste, by which the above problems and disadvantages can be eliminated or at least reduced.

In accordance with a first aspect of the present invention, there is provided a method for processing a pile of waste resulting from mining, comprising the step of adding wood particles to the pile.

Wood particles can be used in the form of wood chips obtained from waste wood, which can be a by-product during mining, more specifically, waste wood in the form of wooden supports used in mining, destroyed during blasting.

Wood chips can be pretreated with acid. As the acid, for example, nitric acid (HNO ₃ ) can be used.

Wood chips can be applied to the surface of the mass of the blade, for example, in the form of a coating.

In one preferred embodiment of the method, the chips are introduced into the mass of the blade, for example by burying it mechanically and / or manually in the mass of the blade.

Chips are preferably introduced into the mass of the blade to a depth of approximately 30 cm below the outer surface of the blade.

Wood chips can be added to the existing mass of a dump laid in the form of a tail dump to restore the vegetation cover on its surface.

However, in one preferred embodiment of the method, the chips are introduced at intervals into the mass of the tail blade during processing.

Wood chips are preferably used in a proportion of 60-90 tons per hectare of tail pile surface.

In addition, in accordance with the present invention, the method comprises an additional step of composting wood chips before performing the step of adding wood chips to the mass of the blade.

In addition, in accordance with the present invention, the step of composting wood chips includes the step of composting wood chips using earthworms.

The composting step of wood chips may include an additional step of mixing the wood chips with another source of organic material.

Another source of organic material may include wastewater.

Wood chips and wastewater can be mixed and left to form compost, after which earthworms can be added to the compost and then kept to form an environment composted using earthworms.

For this purpose, worms of the species Eisenia fetida can be used.

Wood chips and waste water can be mixed in a ratio of 3: 1 or 3: 2, if the number of the latter is not limited.

In accordance with another aspect of the present invention, there is provided a tail blade processed using the above method in accordance with the present invention.

In accordance with another aspect of the present invention, there is provided a medium for treating tailing dumps resulting from mining, comprising a composted mixture of wood particles and another source of organic material.

Wood particles can be wood chips obtained from waste wood, which is a by-product of mining operations.

Wood chips can be obtained from wooden shaft supports destroyed during blasting.

Wastewater can be used as another source of organic material.

This mixture can be further processed by composting using earthworms.

The medium may further include, in a certain way, selected microorganisms.

The implementation of the invention

The present invention will be described below using many examples, with reference to the accompanying drawings and tables. To simplify understanding, each example describes a set of drawings.

EXAMPLE 1

This example is illustrated by the following drawings, in which:

figure 1.1 shows a diagram of the sequence of operations of the method in accordance with the present invention; and

the figure 1.2 shows the end view of the tail dump, representing grass growing on its slopes when restoring vegetation on the surface of the tail dump.

A mining method, including a method for treating or restoring vegetation at a mine tailing dump, in accordance with the present invention, is generally presented in the form of a flowchart depicting the sequence of operations shown in figure 1.1.

The mine may be, for example, mine 10 for the production of platinum (Pt). The produced product and waste, including wood particles in the form of wood chips or pieces of wood, are presented in block 12. Pieces of wood, as is well known, are formed as a result of the destruction of wooden mine supports during blasting operations in the mine. This mixture is fed to flotation separation stage 14, where less dense wood waste is separated in a known manner from more dense platinum and sludge.

The mixture of platinum and sludge at the outlet 16 is separated in block 20 using a well-known method. Platinum is reduced in block 22, and the remaining sludge is pumped in block 24 to a remote location to form a tail blade 26, as is well known in the art.

Wood waste at the exit 18 of stage 14 of flotation separation is subjected to crushing and rolling in block 28, resulting in wood chips 30.

It was determined that the known tailing dumps contain an unacceptably high concentration of hard-to-handle water elements that leach out under the influence of rainwater and fall into the underground water resources, creating pollution of these water resources. Table 1.1 presents the elementary fractions in a sample of wood chips and a sample tail blade, respectively, which are water-soluble and can be washed as described above, and the content of which was determined using the well-known extraction procedure.

Table 1.2 presents the elementary fractions corresponding to the fractions presented in table 1.1 for a mixture in which wood chips 30 are added to tailing dumps 26, as shown in step 32 of figure 1.1.

As a result of the analysis of wood chips and tailings separately, it is obvious that the concentrations of macro elements of tailings contain a high concentration of calcium (Ca), magnesium (Mg), sodium (Na), sulfates (SO ₄ ) and chlorine (Cl). The high SO ₄ content in tailings indicates a high likelihood of acid formation over time. This is confirmed by the low concentrations of bicarbonates (HCO ₃ ) remaining in the sample, which indicates an almost complete depletion of the buffer capacity in the tail dump sample. The need to increase the absorbency was also determined, both by high values of the basic saturation of 21.48%, and by high electrical conductivity (EC) of 2.09 mS cm ^-1 , while assuming that these elements are not currently are included in any compounds, they will be carried out by rains from the tailing dump into groundwater. Of the trace elements, the concentrations of zinc (Zn) and manganese (Mn) exceed the recommended standard values, in addition, potentially toxic heavy metals (Al), nickel (Ni), cobalt (Co) and arsenic (As) are also found in high concentrations in the tailing dump . In contrast, wood chips, although it has a high concentration of Al, is a means of absorbing certain excess concentrations of elements.

It is known that negative surface charges generated on wood chips attract and bind certain elements, and the results presented in Table 1.2 clearly indicate a tendency toward a decrease in the concentrations of Ca, Mg, K, Na, SO ₄ , Cl, Mn, Cu, Zn , Ni and Co while increasing the proportion of introduced wood chips. A decrease in the concentrations of the above elements in the fractions extracted with water is also obviously reflected in a decrease in electrical conductivity (EC) with the introduction of increased volumes of wood chips. As a result of this, the concentration of elements potentially leached and discharged into groundwater gradually decreases as the proportion of introduced wood chips increases.

It was determined that preliminary processing of wood chips with a 0.01% solution of nitric acid (HNO ₃ ) reduces the proportion of introduced wood chips while maintaining the effectiveness of reducing the concentration of potentially toxic elements.

In addition, as described in more detail in Example 5 below, pre-composting wood chips using earthworms (with or without sewage sludge) increases the bulk density of the material introduced into the tail dumps and reduces the composting period.

In addition, it was determined that the proportion of introduced wood chips from 60 tons to 90 tons per hectare of surface of the tail dump allows you to get good results.

As shown in figure 1, 2, which shows the tail blade 26, wood chips, pre-treated with acid, should be introduced into the tail blade 26 to level 34, which is at a depth of approximately 30 cm below the outer surface 36 of the blade. Wood chips are preferably introduced at intervals on the surface of the fixed sides of the blade, as the blade grows over time.

It is assumed that negative surface charges on particles of wood chips significantly increase the ability of cation exchange (CEC), which reduces the removal of potentially toxic elements to groundwater.

The vegetation cover on the tailing dumps can be additionally restored, thanks to the sowing by grass seeds of the surface of the above sides. It is envisaged that at the level of nitrates present on the surface of the sides 38 of the tailing blade, including wood chips, to improve the growth of grass 40, a smaller amount of inorganic fertilizer will be required or inorganic fertilizer will not be required at all.

EXAMPLE 2

In this example, reference is made to the following accompanying drawings, in which:

figure 2.1 shows a diagram of the processing and reproduction of vegetation when performing the method in accordance with the present invention on platinum sludge; and

figure 2.2 presents a graph of RDA (analysis of redundancy), representing the interdependence between the introduction of wood chips (0, 5, 15 and 30 tons ha ^-1 ) and the nutrient capacity of the growth medium. The environmental correlation of plant species for the first axis is 0.749.

Experimental site equipment

The place for the experiment was equipped on platinum tail dumps, and it consisted of sections 24 × 4 m ² in size, which were monitored for a year and a half.

Corresponding schemes for various processing groups are shown in figure 2.1. The experiment included six treatments using three plots of vegetation restoration and four control plots.

Processing 1-3

The first three treatments use a combination of existing practices for restoring vegetation in mines and fertilizing in accordance with accepted standards, but with increased application of wood chips (treatment 1: 5 tons ha ^-1 ; treatment 2:15 tons ha ^-1 ; treatment 3:30 tons ha ^-1 ). A mixture of wood chips treated with canthate and untreated wood chips is used in a 1: 1 ratio. In the first three treatments, the following fertilizers are applied:

a) Superphosphate 1200 kg ha ^-1 b) NH ₄ SO ₄ 350 kg ha ^-1 c) KCl 400 kg ha ^-1

In the first three treatments, the vegetation cover is restored using a mixture of ground shoots and rhizomes of Cynodon dactylon and Cynodon nlemfuensis, collected in close proximity to the tail dump. Cynodon dactylon and Cynodon nlemfuensis are planted in equal proportions of six rows per plot.

Processing 4

The fourth treatment consists in cultivating the soil with the application of 30 tons ha ^{-1 of} wood chips and fertilizers, as in the first three treatments. The vegetation cover is restored on sites using a mixture of seeds, including Cenchrus ciliaris (Molopo) in an amount of 10 kg ha ^-1 , Chloris gayana in an amount of 10 kg ha ^-1 , Eragrostis curvula (PUK E436) in an amount of 5 kg ha ^-1 and Eragrostis lehmanniana in the amount of 5 kg ha ^-1 .

Processing 5

Processing 5 consists in cultivating the soil with the introduction of 30 tons ha ^{-1 of} wood chips and fertilizers, as in the previous treatment. The seed mixture includes a mixture of 5 different types of grasses of the first sowing, 5 different types of perennial grasses and 3 types of potentially creeping grasses (Table 2.1).

Processing 6

Processing 6 consists in cultivating the soil with the introduction of 30 tons ha ^{-1 of} wood chips. Chemical analysis of tailing dumps (Table 2.5) is used to determine the degree of saturation with fertilizers to ensure optimal growth conditions. To improve the nutritional state of the growth medium, fertilizer is applied - monoammonium phosphate (MAP) in the amount of 800 kg ha ^-1 . The vegetation at the sites is restored using a seed mixture similar to the mixture used in processing 5 (Table 2.1).

Materials and methods

Botanical research

Monitoring of the development of vegetation on the site is often monitored using a bridge point device mounted on a 1 m ² frame. In this case, the frequency of occurrence of species and the main coverage of species are determined using 125 points m ^-2 . As a result, the biomass of grass on the vine is determined. The biomass of grass on the root, rooted in a square of 1 m ² , is cut using shearing shears and sorted by species. The biomass is dried at a temperature of 60 ° C for 48 hours and weighed.

Soil sampling and analysis

Soil samples (approximately 500 g) are taken using a soil auger. Fifty gram portions of the sample are used for quantification to determine the particle size distribution according to procedures approved by the American Society for Testing and Materials, 1961. Chemical analysis of soil samples is carried out using a 1: 2 extraction procedure (volume / volume), as described in Black (1965), to determine the water-soluble basic cationic fraction (Ca, Mg, K and Na) and trace elements (Fe, Mn, Cu and Zn), as well as heavy metals (As, Se, Al, Cr, Co, Ni, Pb and Cd).

The content of water-soluble basic cations (Ca, Mg, K and Na), trace elements (Fe, Mn, Cu, Zn) and heavy metals (As, Se, Al, Cr, Co, Ni, Pb and Cd) are determined using quantitative analysis, carried out by atomic absorption spectrophotometry using a Spectr device. AA-250 (Varian, Australia). The content of anions (F, Cl, NO ₃ , PO ₄ and SO ₄ ) is determined by quantitative analysis using an ion chromatograph (Metrohm 761, Switzerland). For analysis using 75 ml of extract 1: 2 soil. The concentration of ammonia (NH ₄ ) is determined by quantitative analysis by the ammonium selective electrode method, as described by Banwart et al. (1972). The content of bicarbonates (HCO ₃ ) in the soil is determined using potentiometric titration with an end point of pH 4.5, using a standard solution of HCl 0.005 M (Skougstd et al., 1979). The concentration of boron (B) is determined by the colorimetric method and using azomethine-N, as described by Barrett (1978), and a VEGA 400 spectrophotometer with an absorption of 420 nm.

The pH and electrical conductivity (EC) of the soil is determined in the extract 1: 2 using a conductivity meter WTW LF92 at a temperature of 25 ° C.

RDA представляет способ константной линейной зависимости, а также прямого градиентного регрессионного анализа (Ter Braak, 1994). Преимущество использования этого способа в качестве инструмента анализа состоит в том, что он обеспечивает графическое представление результата взаимозависимости между переменными и соответствующими (релевантными) факторами окружающей среды. В качестве руководства по токсикологии используют эталонные тесты, в соответствии с рекомендациями Департамента энергии США (Efroymson и др. 1997).Data on vegetation, water content and soil chemistry are analyzed using the STATISTICA version 6 computer program (StatSoft, Inc. 2001). The effects of treatments and wood chip concentration are examined using redundancy analysis - ReDundancy Analysis (RDA)

RDA provides a constant linear relationship method as well as direct gradient regression analysis (Ter Braak, 1994). The advantage of using this method as an analysis tool is that it provides a graphical representation of the result of the interdependence between variables and relevant (relevant) environmental factors. Reference tests are used as a guide to toxicology in accordance with the recommendations of the US Department of Energy (Efroymson et al. 1997).

results

The composition of the vegetation

Tables 2.2, 2.3 and 2.4 summarize the values of the frequency of occurrence of different plant species, the main coating and biomass, measured with six treatments and in control plots. Fourteen species of grass were discovered during the study period. The largest number of grass species was determined after 5 and 6 treatments, in which sowing was carried out using a species mixture of herbs shown in Table 2.2. The mixture of seeds used in processing 4, allowed to obtain the highest total base coat (5.2%). All other treatments, including control plots, had very close base coat values (± 3%). The total amount of biomass in different areas did not differ significantly due to the high variation of root biomass. The total amount of biomass was the largest in the areas where the 6th treatment was carried out. This result was mainly obtained due to the viability of the herb Cenchrus ciliaris.

In terms of frequency of occurrence, size of the main cover and biomass, the grass of Cenchrus ciliaris of the Molopo variety was the most successful species growing from seeds. Satisfactory results also showed the Cenchrus ciliaris species Gayndah (treatment 6), Eragrostis lehmanniana (treatments 4-5) and Eragrostis curvula (treatment 4). Suddenly, Digitaria eriantha, which usually grows very well in areas of vegetation restoration (Mentis 2000), has not sprouted in experimental sites. The likely cause of the unsuccessful planting of Digitaria eriantha grass was the dry conditions at the beginning of the experiment.

Chemical properties of soil

Three samples were taken from the dumps for quantitative analysis of the chemical composition and for determining the level of fertilizer application for treatment 6 (Table 2.5). Samples two and three had a very similar chemical composition, but the nutrient concentrations in sample one were significantly higher than in the previous two samples. This indicates a high variability in the chemical composition of the samples. Extraction with water 1: 2 (Table 2.5) additionally showed that phytotoxicity due to the presence of heavy metals can be a serious problem in untreated dumps. Vegetation growth can be affected by an increased concentration of solutions of Pb, Cr, Co, Se, and especially As in the soil (Efroymson, 1997).

The results of the extraction procedure with water 1: 2 are presented in table 2.6, in the form of the concentration of elements in the soil solution, available for absorption by plants during February 2002. In general, macronutrient concentrations (Ca, Mg, and K) were slightly lower than preferred concentrations for effective growth. The available amount of phosphates and nitrates in the soil solution was also reduced as a result of assimilation by plants. The concentration of NO ₃ and PO ₄ was a limiting factor for plant growth.

With the exception of Cu, micronutrients - nutrients cannot potentially be toxic at this pH level. The concentration of copper - Cu was manifested up to the level of 0.827 mmol / dm ³ (the potential level of phytotoxicity in accordance with Efroymson (1997) is 0.94 (mmol / dm ³ ).

The pH of the growth medium remained at the alkaline level (average pH for all treatments: 7.8 ± 0.025). A low EU value also confirms the low nutritional status of the growth environment and further indicates that salinity is not a problem. SAR sodium absorption rate (SAR) was also lower than the recommended value of 1, which indicates the potential absence of excess soda in the soil.

When comparing Table 2.5 with Table 2.6, you can determine the changes in the chemical properties of the dumps during the growth of vegetation and the introduction of wood chips. The concentration of all macronutrients in the dumps decreased significantly. The concentration of sulfates remained relatively unchanged or slightly decreased in control plots and in areas with a low concentration of wood chips. The concentration of sulfates in the solution of the growth medium also significantly decreased during treatment 6, which was atypical in comparison with other treatments in which 30 tons ha ^{-1 of} wood chips were also used. The concentration of trace elements Fe, Mn, and Cu increased, which indicates an increase in the solubility of these elements. However, zinc and boron concentrations decreased. The pH of the soil solution remained relatively at the same level of 7.8. The electrical conductivity also decreased significantly from an average of 2.267 mS / cm (untreated heaps) to 0.296 mS / cm at the end of the study period.

To explain the effect of the introduced amount of wood chips on the chemical composition of the dumps, an RDA redundancy analysis was performed, its results are graphically presented on a two-dimensional graph of plant species (chemical variables) depending on the amount of wood chips applied as an indicator (Figure 2.2). Since only one variable was monitored during the tests, the canonical axis and the classification axis of species are presented on the first classification axis. Chemical variables by species correlated by 74.9% with the level of application of wood chips, as an environmental parameter. As shown in figure 2.2, of the chemical variables were best associated with the spreading gradient of wood chips B, P and Cu (positive correlation), as well as pH (negative correlation). The pH of the medium shifted towards acids with an increase in the proportion of introduced wood chips, while the concentration of B, and especially Cu, increased. Since the values of the concentration of macronutrients - nutrients (Ca, Mn, K, Na, SO ₄ ) and electrical conductivity (EC) were weakly associated with the first axis of the classification, these variables were less affected by the increase in the amount of introduced wood chips. Table 2.7 shows the correlation matrix between the chemical variable characteristics of the soil. Salinity of the growth medium was mainly formed, in particular, due to sulfates of calcium, potassium, and magnesium. Calcium, magnesium and potassium also correlated strongly. Sodium, however, was better associated with chloride. Iron, manganese and copper correlate with each other. The only significant negative correlation was observed between iron and ammonium.

Conclusions and recommendations

According to the results of restoration of the vegetation cover, a large number of species used, in particular, in the most diverse mixtures, did not sprout. The results proved the sufficiency of using a mixture of grass seeds Cenchrus ciliaris, Eragrostis lehmanniana, Panicum maximum and Eragrostis curvula. Eleusine coracana was the most successful species for the first seeding. A possible explanation for the poor growth of wild grass species is a low level of seeding of 1-2 kg / ha. Seeds (species with a high level of sowing) should be sown in an amount of not less than 5 kg / ha, to ensure successful settlement. Sprouts and shoots of Cynodon dactylon and Cynodon nlemfuensis can also be planted at intervals to control erosion. The use of Cynodon dactylon instead of Cynodon nlemfuensis is preferred because this species is native to the region and is more resistant to arid conditions and more efficiently forms a coating. The results also showed that the seed mixture in treatment 4 was more successful than the seed mixture in treatments 5 and 6. In treatment 4, fewer species were used, but the same results were obtained as when using the seed mixture in treatments 5 and 6. Both seed mixtures provided the same amount of coverage, and the main coating in treatment 4 was denser than in treatments 5 and 6. In accordance with the results, different seed mixtures also did not affect biomass production. The biomass was more influenced by the representation of certain species (in this case, Cenchrus ciliaris) than the total composition of the seed mixture.

The chemical growth conditions at the dumps improved significantly during the experiment. The biggest problem regarding the nutritional status of the soil based on the treated sludge material was its low fertility and possible toxicity of trace elements and heavy metals, especially copper, chromium, selenium and arsenic. Despite the possible phytotoxicity, the energy and viability of the grass were satisfactory. After comparing the chemical composition before processing and after processing the dumps, it turned out that the dumps are easily leachable. This is probably due to a significant problem of possible groundwater pollution.

As a result of the high initial value of the concentration of nitrates, both in dumps and in wood chips, it was assumed that the areas after processing would have an increased concentration of NO ₃ , which, however, did not happen. A likely explanation for this fact is the high mobility of NO ₃ , which leads to the leaching of a significant amount of NO ₃ and a high absorption rate during vegetation, which explains the vigor of vegetation (Mengel & Kirby, 1987). An additional explanation is the immobilization of nitrogen due to the high C / N ratio, as a result of which a certain amount of inorganic nitrogen is fixed in the form of organic nitrogen by soil microorganisms (Tainton 2000).

EXAMPLE 3

In this example, reference is made to the following accompanying drawings, in which:

Figure 3.1 shows a graph of temperature profiles (° C) of composting and composting systems using earthworms during the first 28 days. Here: SS, sewage sludge; WC, wood chips; EM, inoculated with microorganisms; e / w, earthworms;

Figure 3.2 shows a graph of the CO ₂ profiles (%) of composting and composting systems using earthworms during the first 28 days. Here: SS, sewage sludge; WC, wood chips; EM, inoculated with microorganisms; e / w, earthworms; and

Figure 3.3 shows a graph of the O ₂ (%) profiles of composting and composting systems using earthworms during the first 28 days. Here: SS, sewage sludge; WC, wood chips; EM, inoculated with microorganisms; e / w, earthworms.

Materials and methods

Organic waste, earthworm supplementation and microorganism inoculation

Platinum mines receive air-dried samples of wood chips (WC) and sewage sludge (SS). The following types of earthworms (e / w) Eisenia fetida ("tiger worm") are used, which is a groundworm and represents a species that can potentially be used for composting waste (Edwards and Bohlen, 1996). The breeding nursery E. Fetida, used in this study, is kept on cattle manure at a temperature of ± 25 ° С. For the purpose of this study, only sexually mature reproductive worms are used. In bacterial inoculation experiments, a commercially available microorganism preparation (EM ™) is used, which consists mainly of species Pseudomonas, Lactobacillus and Saccharomyces spp.

Earthworm Composting and Composting Experiments

Use a mixture of WC and SS in a ratio of 3: 1 (dry weight kg ^-1 ). The dry ingredients are mixed and moistened with distilled water to 70% (wt.) Moisture content. Explore five treatment groups with three repetitions in each; treatments include the use of mixtures WC + SS, WC + SS + EM, WC + SS + e / w, WC + SS + EM + e / w and WC. The substrate is placed in plastic containers (60 × 40 × 30 cm) and installed in an artificial climate chamber (25 ° C), and composted for 28 days. When processing using earthworms after 28 days of composting, 100 sexually mature worms are introduced to prevent exposure of the worms to possible high temperatures during the initial thermophilic phase of composting.

Physical and chemical parameters

The level of CO ₂ and O ₂ , as well as the temperature, are measured from day 0 (refers to the time of expendable mixing of the waste before decomposition) to day 28 using a portable CO ₂ and O ₂ analyzer (Gas Data PCO ₂ ). In cases of increasing the level of CO ₂ or lowering the level of O ₂ beyond their levels in the air, aeration is increased manually to eliminate this tendency.

At the beginning and at the end of the experiment, the total solids (TS), volatile solids (VS) content, ash content, particle size distribution, NH ₄ ⁺ , NO ₃ ^- , NO ₂ ^- , pH, total and available amount in the soil are determined P (P-Bray 1), total organic carbon (COA (TOC)),% lignin and% cellulose.

The TS content is defined as the residue when dried at 80 ° C for 23 hours and the VS content is measured by ashing the dried samples at 550 ° C for 8.5 hours (APHA et al., 1989). The particle size distribution is determined by sieving 100 g of material through a set of 4 sieves with holes of 4.75, 4.00, 2.00 and 1.00 mm, respectively. Particle size is presented using geometric mean and geometric standard deviation, as described in Ndegwa and Thompson (2001).

Anions NO ₃ ^- , NO ₂ ^{- are} determined by capillary electrophoresis (Waters Quanta 4000, Capillary Electrophoresis System, Waters, MA), as described by Heckenberg et al. (1989). The concentration of NH ₄ ⁺ is determined by quantitative analysis using an ammonium selective electrode, as described by Banwart et al. (1972). The pH of the substrate is determined in the extract 1: 2 using a calibrated pH meter (Radiometer PHM 80, Copenhagen) at a temperature of 25 ° C, after a 12-hour period of equilibration with periodic stirring.

The concentration of P _[sum] is determined colorimetrically using the vanadomolybdate method. The implementation involves pipetting out 200 ml of the sample solution into a 50 ml volumetric flask and adding 10 ml of the vanadomolybdate reagent to the flask, diluting to volume with deionized water and mixing. After 10 minutes, the concentration was read using a colorimetric continuous flow analysis system (Continuous Flow Analysis System, Skalar, Netherlands).

SDAs were determined in an independent laboratory using the Walkley-Black method (Walkley and Black, 1934) and P-Bray 1 using Bray extractant No. 1 (Bray and Kurtz, 1945).

% NRV,% lignin and% cellulose

% NRF (NDF, neutral disintegrating fiber, i.e. insoluble fraction of plant cells),% lignin and% cellulose are determined using the method of Rowland and Roberts (1999). To determine the NRB, the samples are dried and ground (<1 mm). The percentage of dry material is determined by drying air-dried samples for 3 hours at a temperature of 105 ° C and then determine the coefficient of correction of dry weight; i.e. ¹⁰⁰ / _{% dry} .

The reagent consists of a sample of 18.61 g of EDTA (ethylenediaminetetraacetate) and 6.81 g of Na ₂ B ₄ O ₇ · 10H ₂ O, which are dissolved in 500 ml of deionized water, after which 30 g of sodium laurelsulfate (SLS) and 10 ml are added. 2-ethoxyethanol. 4.56 g of anhydrous Na ₂ HPO _{4 are} separately dissolved in water, mixed with the first solution and finally diluted to 1000 ml.

0.5 g of air-dried material was placed in a 250 ml conical flask and 100 ml of neutral cleaning agent added. The solution was brought to a boil and slowly boiled for 1 hour. In the hot state, the solution is filtered through pre-weighed agglomerate (No. 2), applying a small vacuum. The residue is washed with 3 × 50 ml of boiling deionized water and then with acetone until the color is no longer removed, and a vacuum is applied until the fibers look dry. The fibers are then dried for 2 hours at a temperature of 105 ° C, cooled to room temperature in a drying oven and weighed.

The percentage of NRV is calculated by the formula:

% HPB = ^{100 × dry weight correction factor × [(agglomerate weight + fiber weight) - (agglomerate weight)]}

/ _{sample weight} .

To determine lignin, 720 ml of concentrated sulfuric acid diluted with 540 ml of deionized water to 72% (w / v) is used as a reagent. The agglomerate is half-filled with a cooled reagent (15 ° С) H ₂ SO ₄ and mixed until a homogeneous paste is obtained using a glass rod, while the liquid level is maintained by adding H ₂ SO ₄ , as the acid is consumed. After 3 hours, the acid was filtered off under vacuum and the contents washed with hot water and acetone until the residue was free of acid reagent. After that, the agglomerate is dried at a temperature of 105 ° C for 2 hours, cooled in an oven and then weighed. Then it is calcined at a temperature of 550 ° C, cooled in an oven and re-weighed. The percentage of lignin is then calculated by the equation:

% Lignin = ^{(100 × dry weight correction coefficient) × [(sinter weight + lignin + ash weight)]} - / _{sinter weight + ash weight) / sample weight} .

% Cellulose is determined by subtracting the% lignin from the% NRV.

Microbial analysis

The number of living aerobic colony forming units is calculated on the plate as the number of colony forming units (CFU) present per 1 g of sample that developed in 48 hours. Samples were cultured at 25 ° C. on Chromocult agar. The presence of E. coli and Salmonella is determined in an independent laboratory using methods prescribed by the British Standards Institution (1998).

Statistical Data Analysis

The data in this study was analyzed using the SigmaStat® computer software package, and all values are presented as mean ± SD (standard deviation). The probability levels used for statistical significance were P <0.05, and parametric or nonparametric tests were used to compare different treatment groups.

Results and discussion

Temperature profiles during the composting phase (first 28 days) during various treatments are presented in figure 3.1. In none of the treatments did the temperature rise above 33 ° C, which does not meet the requirements of EPA (Environmental Protection Agency) PFRP (treatments to further reduce pathogens), in accordance with the requirements of US-EPA 40 CFR Part 503 (Hay, 19 %). Although an increase in temperature is only an indicator of microbiological activity (Jimenez and Garcia, 1991), the observed lower temperature values were the result of a high moisture content (70%) of the material, and not a lack of microorganisms. Therefore, it is possible that higher temperatures could be obtained if the initial moisture content of the material were lower during loading. Low temperatures, on the other hand, can help maintain nitrogen (N) in the compost material, since high temperatures can lead to high losses of N in the form of NH ₃ in the early stages of composting (Sanchez-Mondero et al., 2001).

In view of the low temperatures and EPA requirements, it was decided to analyze the total content of E. coli and Salmonella spp coli forms. in final products. The presence of stick bacteria is often used as an indicator of the overall sanitary quality of soil and water, and they are easily identifiable (Hassen et al., 2001). E. coli are the most commonly represented bacteria in the group of fecal bacilli (Le Minor, 1984), and therefore they can be used as an indicator of the presence of fecal bacilli. The presence of salmonella is considered as the main problem of the hygienic quality of compost (Hay, 1996), taking into account diseases that may result from contamination.

All E. coli or Salmonella products were not detected, which means that the final products in this study must be safe for general distribution. The total number of sticks was in the range from 2430 to 2903 CFU.

The percentage of CO ₂ and O ₂ in the air is shown in figures 3.2 and 3.3, with the highest activity observed during the first 8 days. This corresponds to an increase in the observed temperature, which is the norm during the normal composting process (Tuomela et al., 2000). The parameters of nutrients (СОУ, Р _[sum] , P-Bray 1, NH ₄ , NO ₂ and NO ₃ ) for various treatments at the time of loading are presented in Table 3.1, and at the time of loading, there were no significant differences (P> 0.05 ), in measured parameters between treatments involving the use of SS. The average percentage change in these parameters after composting and composting using earthworms is presented in Table 3.2. In this case, there is no significant difference (P> 0.05) in the average percentage change in the SDA in different groups. This can occur due to the fact that the temperature during processing does not exceed 33 ° C, and carbon losses in the form of CO ₂ from the systems are minimal.

All treatments, including the use of SS, showed a significant increase in the total P content in the range from 78.60-> 100%. Although the value of P-Bray 1 increased with all treatments, only in the groups SS + WC and SS + WC + EM this increase was statistically significant (P <0.05). The authors of Ghosh et al. (1999) determined that organic waste composted using earthworms emit a larger amount of P-Bray 1. They attributed this to the fact that earthworms use P as a nutrient in their bodies for synthesis and release. the remaining P in mineralized form, and came to the conclusion that composting using earthworms can be an effective way to produce better P top dressing from organic waste. This result differs from other studies in which soluble P content decreases after composting (Vuorinen and Saharinen, 1997) and composting using earthworms (Ndegwa and Thompson, 2001).

The concentration of N in composted waste materials is one of the most important research factors in determining their agronomic value, while the content of NH ₄ and NO ₃ is most interesting, since these compounds can be directly absorbed by plant root systems (Sanchez-Mondero et al., 2001) . The NH ₄ content in all treatments involving the use of SS showed a significant decrease (P <0.05) in the range from 92.57 -> 100%, while treatment using WC showed an increase of more than 100% with the actual the final value of 1.77 ± 0.80 mmol l ^-1 . The NO ₂ content showed a significant increase (P <0.05) for all treatments, including SS, and a non-significant (P> 0.05) change was observed when processing using WC. According to a publication by Sanchez-Mondero et al. (2001), the presence of NO ₂ in a compostable material is an obvious indication of anaerobic conditions during composting. Such conditions can be formed due to the high moisture content in the material, which leads to the development of anaerobic microenvironment. All treatment groups showed a significant increase (P <0.05) NO ₃ in excess of 100%. This can be explained by the fact that during composting the formation of nitrogen-containing compounds occurs as follows:

2NH ₄ ⁺ + 3O ₂ → NO ₂ ^- + 4H ⁺ + 2H ₂ O (Nitrosomonas spp.)

2NO ₂ ^- + O ₂ → 2NO ₃ ^- (Nitrobacter spp.)

However, there are differences between different types of processing with the following ranges of significance (P <0.05); SS + WC + e / w and SS + WC + EM + e / w> SS + WC and SS + WC + EM> WC.

At the end of the study, the concentration of NO ₃ was higher than the concentration of NH ₄ , which indicates the correct course of the composting process (Finstein and Miller, 1985). In addition, the NH ₄ : NO ₃ ratio (Table 3.2) was below 0.16, which indicates compost ripening (Zucconi and de Bertoldi, 1987), in all treatments its value was in the range from 0.011 to 0.0016, except processing using WC (0.27). At the same time, there were no significant differences (P> 0.05) between the values of this ratio in treatments involving SS, which indicates that there is no difference in the development of nitrogen-containing products between composting, sowing of microorganisms and composting using earthworms.

The physical parameters (TS, VS, Ash,% HPB,% lignin and% cellulose) and pH for various treatments at the beginning of the experiment are shown in Table 3.3, without significant differences (P> 0.05) between different groups. The average percentage changes in these parameters after composting and composting using earthworms are presented in Table 3.4, with no significant changes (P> 0.05) when processing using WC. After 112 days of composting and composting using earthworms, the pH value for WC showed a decrease of 5.75% (P> 0.05), while when processing with sewage sludge, its value showed an increase in the range of 13.67 up to 26.47%, and all these values were statistically significant (P <0.05). This corresponds to the main tendency of pH change during composting, when the initial decrease is observed due to the formation of organic acids, after which its value increases as a result of the release of ammonium (Tuomela et al., 2000). The content of TS and ash showed a general increase, and the value of VS and lignin showed a general decrease, but only when composted using earthworms were these changes statistically significant (P <0.05).

According to Neuhauser et al. (1988), an increase in ash content and a decrease in VS are indicators of stabilization of compostable materials. The increase in TS is probably due to the fact that the material that is composted using earthworms is physically destroyed, and therefore its density increases, and also due to the fact that the moisture content (as a function of TS) of the material is significantly lower. A decrease in the volume of material is also observed, although quantitative characteristics have not been obtained for this indicator. Such a decrease in volume and a decrease in moisture content contribute to lower processing and transportation costs.

The percentage of% NRB and% cellulose significantly decreased (P <0.05) in all treatments containing SS, without a significant difference (P> 0.05) between different treatments. Cellulose degradation correlates with microbiomass (Entry and Bachman, 1995); cellulose can also be used by surface earthworms as a direct food source (Zhang et al., 2000). The digestive channels of earthworms, however, reduce the biomass of microbes in the soil (Zhang et al., 2000), which may explain why the degree of cellulose destruction during treatments without earthworms was slightly higher, although it was statistically unreliable (P> 0.05). A significant decrease (P <0.05)% of lignin was observed in only two treatments with composting using earthworms. This may be due to the fact that the destruction of lignin is regulated by the thickness of the material (Tuomela et al., 2000), and earthworms eat, grind and digest organic waste, transforming them into much smaller materials (Aranda et al., 1999).

Entry and Bachman (1995) also concluded that cellulose degradation rather than lignin correlates with the biomass of microorganisms, while Faure and Deschamps (1991) found that inoculation of organic waste by cellulolytic and ligninolytic bacteria does not affect degradation. In addition, earthworms can consume material with a high lignin content, resulting in a stable population size (Senpati et al., 1999).

The particle size analysis results are shown in Table 3.5, where it is expressed as the geometric mean of the size and geometric standard deviation, as well as the percentage change. Composting using earthworms with EM sowing results in the largest reduction in particle size, followed by composting using earthworms without sowing microorganisms. These two groups also showed less heterogeneity, which resulted in a larger value of the observed geometric standard deviation. This is possibly due to the presence of a biologically inactive material, such as plastic (by-products of explosives used in mining), present in wood chips.

Thus, we can conclude that wood chips and sewage sludge, treated on an industrial scale by composting using earthworms, have better qualities compared to materials that simply underwent composting, in view of the decrease in TS and VS, and increase in the content ashes. It was also shown that only composting using earthworms showed a significant decrease in the lignin content and that the addition of microbial culture does not increase the rate of destruction of the material.

EXAMPLE 4

In this example, reference is made to the following accompanying drawings, in which:

4 is a graph of mean body weight (g) ± SD of earthworms (E. fetida) after 84 days (n = 150). * Significantly different (P <0.05). (SS - sewage sludge; WC - wood chips; EM - sowing by microorganisms).

Materials and methods

Air dried wood chips (WC) and SS wastewater sludge were again obtained from platinum mines.

Again used earthworms (e / w) of the species E. fetida ("tiger worm"). For seeding in experiments, a commercially available microorganism preparation (EM ™) is used, which mainly consists of the bacterial species Pseudomonas, Lactobacillus and Saccharomyces, ssp.

Substrates Used

Use a mixture of WC and SS in a ratio of 3: 1 (dry weight kg ^-1 ). The dry ingredients are mixed and moistened with distilled water to 70% (wt.) Moisture content. Two treatment groups with three repetitions in each are examined; treatments include the use of mixtures WC + SS and WC + SS + EM. The substrate is placed in plastic containers (60 × 40 × 30 cm) and installed in an artificial climate chamber (25 ° C), and composted for 28 days. After 28 days of composting, 100 sexually mature worms are introduced. The worm entry delay is used to exclude the effect of possible high temperatures on the worms during the initial thermophilic phase of composting.

Growth and reproduction

Every 14 days for 94 days, after a composting period of 28 days, the biomass of earthworms and the moisture content of the monitored substrates are determined. Biomass is determined by removing 50 worms from each container, washing them in distilled water and drying on paper towels. The worms are then weighed in a water-filled weighing boat using a Sartorius scale. This prevents the worms from being dehydrated, which affects their weight.

The viability of the cocoons is determined by randomly selecting 72 cocoons from each container and placing them in many plates filled with distilled water. Water in trays is replaced every third day to prevent the growth of bacteria, which can adversely affect the results. The number of hatched cocoons and the number of hatchings per cocoon are recorded for four weeks.

Heavy metal analysis

Nine earthworms per group are removed from the substrate before and after the experiment. After this, the worms are placed on wet filter paper in Petri dishes for a period of 24 hours, to cleanse the contents of their intestines. This is done to avoid distortion of the results with respect to the actual content of heavy metal in the tissues of the worm due to the presence of heavy metals in the contents of the intestine. After this period, at 24 hours, the worms are washed in distilled water, dried on paper towels and killed by freezing. They are individually weighed and frozen (-74 ° C) in multifaceted tubes to analyze for the presence of heavy metals in subsequent steps. Substrate samples are also taken, placed in plastic bags and cooled until analysis for the content of heavy metals. Samples of worms and compost insist, as prescribed by Katz and Jennis (1983). The samples are individually dried and ground, after which they are burned at a temperature of 550 ° C. After that, they are individually placed in test tubes and add 10 ml of nitric acid (HNO ₃ ) with a concentration of 55%. Samples are left overnight at room temperature to begin the infusion process. The next day, the samples are heated to a temperature of 40-60 ° C for two hours and then to a temperature of 120-130 ° C for an hour, after which they are left to cool. Then add 1 ml of perchloric acid (HclO) with a concentration of 70%, and this mixture is reheated to a temperature of 120-130 ° C for one hour. After cooling the samples add 5 ml of distilled water. The samples are then reheated to a temperature of 120-130 ° C until steam is released. After the final cooling of the samples, they are microfiltered.

The solutions are filtered through Whatman No. 6 filter paper into 20 cm ³ volumetric flasks using Sartorius microfilter holders and plastic syringes. The filtered solution is diluted with distilled water to 20 cm ³ . Microfiltrate these solutions with a volume of 20 cm through 0.45 μm Sartorius Cellulose Nitrate filter paper into polyvinyl containers and analyze using inductively coupled plasma spectroscopy (ICP-AES) to determine the presence of various metals.

Statistical Data Analysis

The data in this study is analyzed using the SigmaStat® computer software package, and all values are presented as mean ± SD (standard deviation). The probability levels used for statistical significance are P <0.05, and parametric or nonparametric tests are used to compare groups.

results

No mortality cases were observed at any of the stages of the study, and the average values of the change in the biomass of E. fetida are presented in Figure 4. Before introducing into the mixture for processing the average biomass of earthworms when processing SS + WC was 0.44 ± 0.01 g and 0 , 43 ± 0.02 g when processing SS + WC + EM. No significant (significant) differences were observed between these two values (P> 0.05). On day 14, the average biomass of earthworms reached a maximum value of 0.81 ± 0.02 g and 0.77 ± 0.02 g in the groups SS + WC and SS + WC + EM, respectively, so both of these values are significant (P < 0.05) exceeded the initial biomass value. From 14 to 84 days, the average biomass decreased to 0.49 ± 0.03 g in SS + WC and 0.51 ± 0.01 g in SS + WC + EM, a significant difference (P <0.05) between the two values. Both of these values were significantly (P <0.05) higher than the initial biomass value.

The average hatching of cocoons produced in the SS + WC group was 46.8 ± 2.4% (n = 216), which was significantly lower than 68.0 ± 2.8% (n = 216) in the SS + WC + group EM. The average number of hatchings per cocoon was 2.7 ± 0.1 for SS + WC and 3.0 ± 0.2 for SS + WC + EM groups, and there was no significant difference (P> 0.05) between the two values.

The content of heavy metals in two mixtures of the substrate for Al, As, Cu, and Ni is given in Table 4.1, and it was determined that for the selected metals there were no significant differences (P> 0.05). The initial and final dose loads of heavy metals, manifested in the tissues of earthworms, are presented in Table 4.2. Initially, there was no statistical difference (P> 0.05) between the concentrations of heavy metals in the tissues of earthworms in the two groups. After the experiment, the content of heavy metals in the tissues of earthworms using SS + WC was significantly higher (P <0.05) than at the beginning for all heavy metals that were measured, with the exception of As, the content of which was below the sensitivity limit 0 05 mcg g ^-1 . In the tissues of earthworms, which were used in the SS + WS + EM group, the content of heavy metals did not significantly change after 84 days (P> 0.05). The bioconcentration index (BCF) for various heavy metals in earthworm tissues after 84 days of the composting period using earthworms is shown in Table 4.3. Obviously, the earth worm PBC in the SS + WC group was almost twice as high as in the SS + WC + EM groups for Al, Cu, and Ni.

Discussion

From these results (Figure 4 and Tables 4.1-4.3) it is obvious that earthworms in both treatment groups are exposed to a mixture of pollutants, among other things, Al, Cu and Ni. This makes it difficult to assess the effect of toxic substances, since the actual risk of the organism was determined by the presence of these toxic substances. The effects of Cu (Spurgeon and Hopkin, 1995; Van Gestel et al., 1991) and Ni (Lock and Janssen, 2002; Scott-Fordsmand et al., 1998) on growth and reproduction are well documented, but little information is currently available. about the effect of aluminum, or no such data at all. In addition, there is no literature on the effects of these metals in mixtures on E. fetida worms. Regarding the harm that these metals can cause in land cover restoration programs, Al, Cu and Ni are more dangerous than the ranges proposed by DWAF (1996) for use in agriculture. This should be taken into account when choosing the types of plants used to restore the vegetation cover, as well as when tracking the amount of these metals that seep into the groundwater.

Growth data were compared with previous studies where it was determined that E. fetida worms reached an average biomass of ± 0.45 g under optimal conditions (Reinecke et al., 1992). The fact that the average "biomass of worms in the SS + WC groups was significantly lower (P <0.05) than that shown for SS + WC + EM treatments can directly affect the bioavailability of heavy metals in these substrates. However, both groups showed a decrease in biomass after 14 days (Figure 4), which can be attributed to the presence of elevated concentrations of heavy metals. Therefore, growth can be considered as a sensitive parameter in assessing the effects of Al, Cu and Ni for E. fetida. This is consistent with the results of previous studies on the effect of Cu in the form of CuNO ₃ on growth (Reinecke and Reinecke, 1996), as a result of which it was determined that a negative effect on the growth of E. fetida affects at concentrations of 200 μg g ^-1 .

Thus, regarding growth as an endpoint, it can be concluded that composting wood chips and sewage sludge using earthworms of E. fetida is economically acceptable. Considering the fact that earthworms in a mixture containing microorganism inoculation developed better, by choosing the average biomass as the endpoint, it can be expected that better results can be obtained for full-scale composting technologies using earthworms.

The average hatching value, which can be considered as the endpoint for reproductive development, was significantly higher (P <0.05) for the SS + WC + EM group than for the SS + WC group, although there was no difference (P> 0, 05) the average number of hatching between these types of processing.

Venter and Reinecke (1988) concluded that the average hatchability of cocoons produced by E. fetida was 73%, and that each cocoon produced an average of 2.7 hatched larvae. A hatching level of 68% of the worms in the SS + WC + EM mixture was preferable when compared with the 73% value set by Venter and Reinecke (1988), although the hatching rate of cocoons using the SS + WC mixture was significantly lower, at 45%. Data related to hatching in the SS + WC substrate with high concentrations of Ni (551 μg · g ^-1 ) and Cu (315 μg · g ^-1 ) were consistent with the results of the authors of previous studies. Lock and Janssen (2002) note that EC ₅₀ for Ni, based on cocoon production, is 362 μg · g ^-1 , while Spurgeon and Hopkin (1995) found that the reproduction of earthworms is significantly reduced when copper is contaminated with soil. Reinecke and Reinecke (1996) determined that E. fetida did not produce cocoons at a Cu concentration of 200 μg · g ^-1 . An increase in hatchability is therefore a much more sensitive parameter than growth when assessing the potential for using E. fetida in composting wood chips or sewage sludge using earthworms.

The fact that the increase in hatchability in groups seeded with microorganisms was higher can probably be related to the fact that Ni and Cu, which have a negative effect on reproduction, are less accessible to earthworms in this case. Microorganisms allow active (bioaccumulation) and passive (biosorption) concentration of metals (Unz and Shuttleworth, 1996). It was experimentally shown that Saccharomyces (Simmons et al., 1995) and Pseudomonas (Churchill et al., 1995), both of which were present in seeding, show wide changes in metal biosorption. This may explain the differences in growth and reproductive data between the two groups. This fact can be verified by the level of dose loading with heavy metals determined in the tissues of earthworms, when the worms in the substrate containing microorganism inoculated had significantly lower (P <0.05) levels of Al, Cu, and Ni, which also reflected in the calculated values PBC.

findings

It can be concluded that the growth of worms of the species E. fetida does not slow down when used for composting using earthworms from industrially produced wood chips and sewage sludge, or when microorganism inoculates it. The reproductive development of earthworms in the treatment groups SS + WS decreased, and bioconcentration of Al, Cu, and Ni was observed in their tissues. Earthworms in the treatment group with the addition of inoculation with microorganisms, in contrast, did not show bioconcentration of heavy metals in their tissues and had a significantly higher reproductive development than in the treatment groups without inoculation of microorganisms. This indicates that the microorganisms present in the sowing make heavy metals present in mixtures of wood chips and sludge sewage, inaccessible as a result of their biosorption and bioaccumulation.

Thus, we can conclude that the most economically feasible method of bioconverting wood chips and sewage sludge using E.fetida worms is a method with the addition of seeding by microorganisms.

EXAMPLE 5

In this example, reference is made to the following accompanying drawings, in which:

figure 5 shows a perspective view of a shaft for composting, and composting using earthworms medium for processing the mass of waste mining, in accordance with the present invention.

According to the results of experimental studies, it was concluded that for successful composting of wood chips (WC) and sewage sludge (SS), it is necessary to use them in a ratio of 3: 1 when mixing and to carry out the composting / composting process using worms for 4-6 months .

In the commercial embodiment of the method in accordance with the present invention, the first step is to compost the WC and SS mixture for 30 days with the construction of a shaft, an example of which is shown in figure 5. After that, the material is covered with a net (to prevent the extermination of worms by birds) and composted using earthworms (Eisenia fetida) for 4-5 months with a ratio of 25 g of worms per kg of material.

The optimal shaft dimensions were determined as 2 tons of compost mixture per meter length at a height of 1 m and a width of 2 m, as shown in Figure 5. This implies the use of 50 kg of earthworms per shaft.

The compost medium obtained and the earth composted using earthworms are then mixed with the waste, as described above in Examples 1 and 2.

It has been determined that a composting environment and an earthworm composting environment, in accordance with the present invention, are a preferred alternative and / or addition to using a topsoil to improve soil, as well as to treat wood chips waste and sewage sludge that represent are the main sources of organic carbon and nitrogen and are significant sources of nutrients and organic matter in bioprocessing in accordance with this image eteniem. Wood chips are also preferred for use as a source of organic matter used to cultivate the soil during restoration of the vegetation cover, and this is the main argument in favor of introducing wood chips to improve cation exchange, which decreases base saturation and improves the ability sludge to absorb excess salts. Wood chips also improve the physical properties of the growth medium by increasing the ability to retain water. Organic material also stimulates biological activity, which is essential for restoring the nutrient medium.

Another advantage of the present method is that mining waste in mines, such as sludge, wood chips and wastewater, is used to recover dumps and to reduce soil, groundwater and air pollution.

It should be understood that in relation to the composition and method in accordance with the present invention, various variations are possible in the details when processing dumps formed during mining, without departing from the scope of the attached claims.

APPENDIX A: TABLES

Table 1.1 Macronutrients Sample No. Sa Mg K Na P SO ₄ NO ₃ NH ₄ Cl NSO ₃ mmol l ^-1 Wood chips 1,08 0.95 1.95 0.56 0.02 2.26 0.67 0.27 0.82 0.55 Dumps 5.22 3.28 0.55 3.15 0,03 8.59 1.49 0.08 3.25 0.33

Trace elements and other data P-BRAY I ppm Sample No. Fe Mn Cu Zn AT PH The EU F mol l ^-1 ms cm ^-1 Wood chips 31.24 0.52 0.05 0.36 fifteen 6.68 0.69 1.71 Dumps 1,57 37.60 0.28 2.44 eleven 5.62 2.09

Heavy metals Sample No. Al Pb Cr Ni Co Cd Se As mg l ^-1 Wood chips 8.52 0.00 0.09 0.00 0.00 0.00 0.00 0.39 Dumps 6.10 0.00 0.04 32.28 1,58 0.01 0.05 1,03

Table 1.2 Macronutrients Sample No. Sa Mg K Na P SO ₄ NO ₃ NH ₄ Cl NSO ₃ mmol l ^-1 T500 C100 4,51 2.93 0.46 3.02 0.02 8.19 0.23 0.06 2.93 0.10 T500 C200 3.91 2.60 0.42 2.74 0.04 6.91 0,07 0.05 3.10 0.20 T500 C300 3.21 2.16 0.37 2,34 0.02 5.73 0.08 0.05 2.44 0.20 T500 C400 3.44 1.94 0.39 2.04 0,03 5.53 0.22 0.04 2.24 0.29 T500 C500 2.45 1.12 0.30 1.17 0,03 3.37 0.31 0.04 1.20 0.52

Trace elements and other data Sample No. Fe Mn Cu Zn AT pH The EU F mol l ^-1 ms cm ^-1 T500 C100 0.35 34.48 1.27 2.01 0 5.65 1.85 T500 C200 0.48 23.51 0.51 0.98 0 6.41 1,63 T500 C300 0.00 16.80 0.43 0.83 0 6.44 1.36 T500 S400 0.78 15.38 0.39 0.69 0 5.52 1.34 T500 C500 0.91 4.18 0.20 0.31 0 7.17 0.87

Heavy metals Sample No. Al Pb Cr Ni With Cd Se As mg l ^-1 T500 C100 0.09 0,000.00 0,090,06 33.59 2,39 0.01 0.36 0.70 T500 C200 0.00 0,000.00 0,060,06 28.50 1.35 0,000 0.46 1.10 T500 C300 0.00 0.00 0.06 23.42 0.89 000.00 0.83 1.14 T500 S400 0,000.00 22.66 0.84 0.00 1.18 1.40 T500 C500 11.24 0.29 1.28 1,66

Table 2.1 Types of plants used in the mixture during processing 6 Kinds Kg / ha Types of grasses first sowing Enneapogon cenchroides 2 Melinis repens one Chloris virgata one Urochloa brachyura one Eleusine coracana one Types of perennial herbs Cenchrus ciliaris variety Molopo 2 Cenchrus ciliaris variety Gayndah 2 Eragrostis lehmanniana one Panicum maximum 3 Digitaria eriantha 3 Types of Creeping Grasses Cynodon dactylon four Chloris gayana one Bothriochloa insculpta 2 Total 24

Table 2.2 The average number of plants by species included in the main coating, determined during March 2001 and February 2002 at experimental sites on platinum sludge treated with 5.15 and 30 tons ha ^{-1 of} wood chips, and using three different ways to restore vegetation. Processing 1 Processing 2 Processing 3 Processing 4 Processing 5 Processing 6 Control plot Empty ground 76.71 ± 2.05 74.76 ± 2.47 84.98 ± 2.19 66.58 ± 7.34 75.47 ± 2.56 76.18 ± 2.32 70.82 ± 2.98 Cenchrus ciliaris (gayndah) 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 12.98 ± 4.65 2.76 ± 1.84 Cenchrus ciliaris (Molopo) 2.84 ± 1.07 0.00 ± 0.00 0.00 ± 0.00 4.00 ± 1.12 13.51 ± 1.38 7.11 ± 3.10 0.82 ± 0.38 Chloris gayana 1,07 ± 0.87 1.42 ± 0.82 1.16 ± 0.88 0.18 ± 0.18 0.53 ± 0.38 0.00 ± 0.00 0.98 ± 0.55 Chloris virgata 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.44 ± 0.44 0.04 ± 0.04 Cynodon dactylon 13.16 ± 1.26 14.04 ± 1.76 5.96 ± 1.69 0.18 ± 0.18 0.44 ± 0.19 0.53 ± 0.53 13.87 ± 3.22 Cynodon nlemfuensis 6.04 ± 1.33 8.89 ± 1.44 7.73 ± 2.29 0.00 ± 0.00 0.27 ± 0.27 0.00 ± 0.00 8.58 ± 2.24 Eleusine coracana 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 2,58 ± 1.30 1.24 ± 0.64 0.09 ± 0.09 Enneapogon cenchroides 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.36 ± 0.36 0.27 ± 0.13 0.09 ± 0.09 Eragrostis chloromelas 0.00 ± 0.00 0.00 ± 0.00 0.09 ± 0.09 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 Eragmstis curvula 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 9.24 ± 2.22 0.80 ± 0.46 0.00 ± 0.00 0.53 ± 0.44 Eragrostis lehmanniana 0.00 ± 0.00 0.00 ± 0.00 0.09 ± 0.09 19.82 ± 8.78 3.91 ± 1.22 0.98 ± 0.51 1.42 ± 0.95 Panicum maximum 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 2.04 ± 1.33 0.00 ± 0.00 0.00 ± 0.00 Urochloa mosambicensis 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.27 ± 0.27 0.00 ± 0.00

Table 2.3 The average number of plants by species included in the main coating, determined during March 2001 and February 2002 at experimental sites on platinum sludge treated with 5, 15 and 30 tons ha ^{-1 of} wood chips, and using three different ways to restore vegetation. Processing 1 Processing 2 Processing 3 Processing 4 Processing 5 Processing 6 Control plot Cenchrus cilliaris (gayndah) 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 1.78 ± 0.79 0.44 ± 0.28 Cenchrus cilliaris (molopo) 0.36 ± 0.14 0.00 ± 0.00 0.00 ± 0.00 0.36 ± 0.27 2.04 ± 0.44 1.42 ± 0.72 0.14 ± 0.08 Chloris gayana 0.18 ± 0.12 0.62 ± 0.32 0.27 ± 0.19 0.00 ± 0.00 0.09 ± 0.09 0.00 ± 0.00 0.22 ± 0.13 Chloris virgata 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.09 ± 0.09 0.00 ± 0.00 Cynodon dactylon 2.40 ± 0.60 1.24 ± 0.46 1.16 ± 0.36 0.00 ± 0.00 0.00 ± 0.00 0.09 ± 0.09 1,69 ± 0.54 Cynodon nlemfuensis 0.89 ± 0.39 1,60 ± 0.38 1.16 ± 0.52 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.62 ± 0.21 Eleusine coracana 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.36 ± 0.19 0.09 ± 0.09 0.00 ± 0.00 Eragrostis curvula 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 1,69 ± 0.51 0.09 ± 0.09 0.00 ± 0.00 0.11 ± 0.11 Eragrostis lehmanniana 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 3.11 ± 1.24 0.36 ± 0.19 0.18 ± 0.12 0.36 ± 0.27 Panicum maximum 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.27 ± 0.19 0.00 ± 0.00 0.00 ± 0.00 Urochloa mosambicensis 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.09 ± 0.09 0.00 ± 0.00 Total 3.82 3.47 2,58 5.16 3.20 3.73 3,59

Table 2.4 The average biomass value of plant species collected during March 2002 in experimental platinum sludge plots treated with 5, 15, and 30 tons ha ^{-1 of} wood chips and using three different methods of plant cover restoration. Treatment Processing 1 Processing 2 Processing 3 Processing 4 Processing 5 Processing 6 Control plot Bothriochloa insculpta ^NS 0.00 0.00 0.00 0.00 0.00 0.00 3.83 ± 3.83 Cenchms ciliaris ^NS 374.70 ± 239.33 52.37 ± 50.18 0.00 317.97 ± 58.12 301.43 ± 78.66 503.67 ± 206.15 105.67 ± 70.94 Chloris gayana ^NS 0.00 0.00 0.00 0.00 0.00 0.00 23.80 23.80 Cynodon dactylon * 40.90 ± 20.97 155.30 ± 51.91 61.23 ± 20.71 0.00 0.00 0.00 63.85 ± 30.06 Cynodon nlemfuensis ^NS 51.13 ± 30.88 26.03 ± 20.69 93.37 ± 40.69 0.00 0.00 0.00 35.03 ± 21.14 Eragrostis chloromelas ^NS 0.00 0.00 0.00 0.00 ± 10.50 0.00 0.00 0.00 Eragrostis echinochloidea ^NS 0.00 0.00 0.00 0.00 ± 15.68 0.00 0.00 0.00 Eragrostis lehmanniana ^NS 0.00 0.00 7.97 ± 4,59 68.60 ± 37.56 19.37 ± 17.94 0.90 ± 0.90 36.17 ± 33.70 Panicum maximum 0.00 0.00 0.00 0.00 50.07 ± 30.38 13.87 ± 13.62 17.60 ± 17.60 Total ^ns 466.73 ± 204.04 233.70 ± 36.24 162.57 ± 16.35 412.73 ± 73.08 370.87 ± 61.61 518.43 ± 196.12 285.95 ± 70.43 *, **, *** Significance shown at a probability level of 0.05, 0.01 and 0.001

Table 2.5 Chemical properties of soil based on platinum sludge and wood chips obtained by processing minerals at the Impala Platinum platinum mine, where experiments on the introduction of wood chips were recorded. Macronutrients Sample No. Sa Mn K Na P SO ₄ NO ₃ NH ₄ Cl NSO ₃ mmol dm ^-3 Dumps 3,51 3.45 1.23 6.54 0,03 3.21 2.93 3.04 9.50 1.77 Wood chips 1,08 0.95 1.95 0.56 0.02 2.26 0.67 0.27 0.82 0.55 Trace elements and other data Sample No. Fe Mn Cu Zn AT pH EC μmol dm ^-3 msm m ^-1 Dumps 1,50 0.35 0.05 0.20 7 7.71 2.17 Wood chips 31.24 0.52 0.05 0.36 fifteen 0.68 6.68 Heavy metals Sample No. Al Pb Cr Ni Co Cd Se As mg dm ^-3 Dumps 0.23 0.02 0.08 0.04 0,03 0.00 0.48 0.50 Wood chips - - - - - - - -

Table 2.6 The averaged chemical properties of growth medium samples collected at platinum sludge treatment sites fertilized with 5, 15, 30 tons ha ^-1 wood chips and using three methods of restoration of vegetation cover. The average error value (Mean) and the standard error value (St. st.) Were combined for all sections (All), data for treatments 1-6 and control sections (C) are shown. Processing All one 2 3 four 5 6 FROM Recommended Value Sa mmol dm ^-3 Average 0.693 0.713 0.530 1,097 1,090 0.937 0.323 0.425 1,08 St.osh. 0,071 0.147 0,120 0,075 0.156 0,110 0,044 0,095 Mg Average 0.418 0.343 0.360 0.643 0.557 0.617 0.217 0,303 0.64 St.osh. 0,043 0,044 0,026 0,047 0.139 0,096 0,064 0,089 K Average 0.375 0.433 0.333 0.540 0.403 0.490 0.223 0.290 0.8 St.osh. 0,027 0,066 0,060 0,075 0,030 0.056 0,037 0,032 Na Average 0.329 0.187 0.287 0.337 0.397 0.380 0.287 0.380 St.osh. 0,037 0,083 0.056 0.013 0.198 0,044 0,089 0,096 R Average 0.007 0.005 0.017 0.014 0.005 0.010 0.004 0,000 0.02 St.osh. 0.002 0.005 0.017 0.007 0.005 0.005 0.004 0,000 SO ₄ Average 0.884 0.925 0.485 1,497 1,478 1,488 0.273 0.462 St.osh. 0.136 0.156 0.211 0.165 0.436 0.278 0,084 0.263 NO ₃ Average 0,031 0.014 0,080 0,040 0,021 0.011 0,026 0,030 2.1 St.osh. 0.006 0.008 0,030 0.015 0.009 0.006 0.003 0.004 NH ₄ , Average 0,030 0,038 0,026 0,036 0,039 0.011 0,020 0,034 0,03 St.osh. 0.003 0.006 0.003 0.003 0.005 0.011 0.004 0.006 Cl Average 0.142 0,066 0,132 0.153 0.138 0.179 0.138 0.164 St.osh. 0.012 0.014 0.014 0,038 0,045 0.019 0,026 0,028 NSO ₃ Average 0.976 0,800 1,167 1,033 1,043 0,800 0.867 1,050 0.8 St.osh. 0,043 0,076 0,067 0,101 0.106 0,029 0.136 0.104 Fe μmol dm ^-3 Average 4,362 1,120 4,050 3,420 3,307 6,913 7,677 4,203 178.57 St.osh. 0.552 0.555 1,282 1,947 0.875 0.569 0.928 1,027 Mn Average 0.873 0.010 0.913 0.580 0.930 1,320 1,350 0.940 72.73 St.osh. 0.119 0,000 0.446 0.059 0.462 0.153 0,087 0.210 Cu Average 0.562 0.420 0.603 0.477 0,600 0.733 0.827 0.418 0.94 St.osh. 0,039 0.104 0,091 0,086 0.059 0,023 0,069 0.059 Zn Average 0.014 0.013 0.013 0,020 0.013 0.010 0.013 0.015 6.12 St.osh. 0.002 0.003 0.003 0.010 0.003 0,000 0.003 0.005 AT Average 2,873 1,384 0.478 7,411 2,340 2,246 5,259 1,934 92.59 St.osh. 0.516 0.384 0.239 1,042 1,340 0.623 1,042 0.558 pH Average 7,824 7,777 7,867 7,763 7,730 7,803 7,803 7,925 6.5-7.2 St.osh. 0,025 0,029 0,094 0,052 0.051 0.018 0,087 0,060 The EU msm m ^-1 Average 0.296 0.277 0.243 0.440 0.413 0.400 0.163 0.217 0.4-0.8 St.osh. 0,027 0,039 0,038 0,021 0,079 0.051 0,033 0,050 SPN Average 0.456 0.260 0.429 0.362 0.412 0.431 0.536 0.610 <1 St.osh. 0,040 0.107 0,070 0,021 0.174 0,022 0.142 0,070

Table 2.7 Significant correlation between nutrients in a growth medium solution taken from experimental plots treated with wood chips during March 2002 at Impala Platinum mine. Sa Mg K Na SO ₄ NH ₄ Cl Fe Mn Cu 0.896 *** Mg K 0.825 *** 0.735 *** Na 0.412 * 0.670 *** 0.261 SO ₄ 0.958 *** 0.949 *** 0.783 *** 0.578 ** NH ₄ 0.166 0.167 0,089 0.137 0.190 Cl 0.220 0.504 ** 0.248 0.840 *** 0.364 -0.062 Fe -0.346 -0.157 -0.190 0,034 -0.310 -0.511 ** 0.340 Mn -0.171 0,049 -0.225 0.316 -0.102 -0.217 0.443 * 0.622 *** Cu 0.051 0.122 0,083 0.222 0,052 -0.410 * 0.3253 0.607 ** 0.651 *** EC 0.966 *** 0.972 *** 0.817 *** 0.606 *** 0.980 *** 0.177 0.425 * -0.249 -0,052 0.106 *, **, *** Significance at 0.05, 0.01 and 0.001

Table 3.1 Nutrient parameters (± SD) in the proportions of the mixture at the time of loading (n = 9). SOU P _sum P-brayl NH ₄ NO ₂ NO ₃ Process g kg ^-1 mg l ^-1 WC 93.40 ± 6.82 ^a <0.01 ^a 7.18 ± 0.08 ^a 0.74 ± 0.12 ^a 1.03 ± 0.24 ^a 0.90 ± 0.32 ^a SS + WC 63.00 ± 0.87 ^a 132.06 + 66.85 ^b 440.72 ± 22.79 ^b 278.46 ± 20.03 ^b 5.90 ± 0.75 ^b 8.06 ± 2.60 ^b SS + WC + EM 67.20 ± 1.29 ^a 65.30 ± 6.61 ^b 421.49 ± 49.4 ^b 356.31 ± 47.68 ^b 6.10 ± 1.62 ^b 8.87 + 2.82 ^b SS + WO + e / w 68.50 + 1.79 ^a 100.57 ± 37.58 ^b 422.89 ± 37.92 ^b 331.59 ± 32.45 ^b 4.76 + 2.76 ” 7.45 + 5.63 ^b SS + WO + EM + e / w 79.30 ± 0.79 ^a 112.03i15.65 ^b 369.40 ± 12.84 ^b 220.80 ± 24.99 ^b 6.92 ± 0.18 ^b 10.06 + 7.70 ^{b a, b The} average values with the same letter index did not differ significantly (P <0.05) SDA, the total content of organic carbon; P-Bray 1, extracted from soil P; SS, sewage sludge; WC, wood chips; EM, inoculated with microorganisms; e / w earthworms

Table 3.2 The average percentage change in the amount of nutrients during composting and composting using earthworms after 112 days (n = 9) depending on the different types of treatment ^a and the ratio of NH ₄ : NO ₃ . Process Change (%) ^b NH ₄ : NO ₃ ratio SOU P (sum) P-Bray 1 NH ₄ NO ₂ NO ₃ WC -90.40 Nd 3.57 ^a > 100 ^{* a} -11.65 ^a > 100 ^{* a} 0.27 SS + WC 15.60 > 100 ^{* a} 24.81 ^{* b} -99.23 ^{* b} 55.11 ^{* b} > 100 ^{* b} 0.0016 SS + WC + EM 12.15 78.60 ^{* a} 21.06 ^{* b} -> 100 ^{* b} 39.34 ^{* b} > 100 ^{* b} 0.0018 SS + WC + e / w 4.35 > 100 ^{* a} 19.28 ^c -92.57 ^{* b} > 100 ^{* a} > 100 ^{* c} 0.011 SS + WC + EM + e / w -3.46 > 100 ^{* a} 19.44 ^s -98.31 ^{* b} 76.41 ^{* b} > 100 ^{* c} 0.0025 Significantly different (P <0.05) from the initial content ^and a, b, c - Average values with the same letter index did not differ significantly (P> 0.05) ^b Change (%) = [(Initial value-final) / Initial] × 100 ND: Not detected; СОУ, total content of organic carbon; P-Bray 1, amount of P extracted from the soil; EM, inoculated with microorganisms; e / w earthworms; SS, sewage sludge; WC, wood chips

Table 3.3 Physical parameters (± S.D.) in the proportions of the mixture at the time of loading (n = 9). Process pH TS VS Ash NRV Lignin Cellulose g kg ^-1 WC 6.79 + 0.06 520.53 ± 7.28 ^a 493.17 ± 6.67 ^a 267.02 ± 6.87 ^a 986.68 + 1.30 ^a 266.34 + 3.33 720.34 + 4.59 ^a SS + WC 5.21 ± 0.03 485.00 + 1.44 ^a 246.18 ± 0.98 ^a 365.68 ± 1.57 ^a 975.92 ± 1.35 ^a 223.24 ± 1.41 ^a 752.67 + 0.63 ^a SS + WC + EM 5.49 ± 0.08 468.90 ± 2.22 ^a 237.39 ± 3.52 ^a 358.11 ± 3.35 ^a 973.92 + 0.57 ^a 247.49 + 2.09 ^a 726.42 + 1.55 ^a SS + WC + e / w 5.21 ± 0.06 421.57 ± 1.99 ^a 244.66 ± 0.10 ^a 322.83 ± 2.25 ^a 968. 11 ± 0.85 ^a 259.79 + 3.50 ^a 708.32 + 4.30 ^a SS + WC + EM + e / w 5.30 ± 0.11 403.33 ± 0.52 ^a 251.54 + 0.31 ^a 301.88 ± 0.41 ^a 928.71 ± 5.95 ^a 225.29 + 1.58 ^a 703.41 ± 5.05 ^{a a, b The} mean values with the same letter index did not differ significantly (P <0.05) TS, total solids content; VS, volatile solids content; NRV, neutral loosening fiber; EM, inoculated with microorganisms; e / w earthworms; SS, sewage sludge; WC, wood chips

Table 3.4 Comparison of the average percentage change in physical parameters depending on various types of processing ^a (n = 9). Process Change (%) ^b pH TS VS Ash HPB Lignin Cellulose WC -5.75 ^a -4.04 ^a -7.19 ^a 1.43 ^a -0.40 ^a -2.38 ^a -0.33 ^a SS + WC 25.99 ^{* b} 0.81 ^b -10.48 ^b 4.34 ^b -28.11 * ^b -13.14 ^b -32.55 ^{* b} SS + WC + EM 13.67 ^{* b} 7.29 ^b -10.72 ^b 9.92 ^b -31.55 ^{* b} -9.77 ^b -41.10 * ^b SS + WC + e / w 26.47 * ^b 18.81 ^{* c} -14.91 ^{* c} 21.30 ^{* c} -29.08 ^{* b} -26.09 ^{* c} -28.29 * ^b SS + WC + EM + e / w 18.93 ^{* b} 30.58 ^{* c} -28.12 ^{* c} 42.94 * ^c -28.55 ^{* b} -16.78 ^{* c} -31.37 * ^b Significantly different (P <0.05) from the initial content ^and a, b, c - Average values with the same letter index did not differ significantly (P> 0.05) ^b Change (%) = [(Initial value - final) / Initial] × 100 TS, total solids content; VS, volatile solids content; NRV, neutral loosening fiber; EM, inoculated with microorganisms; e / w earthworms; SS, sewage sludge; WC, wood chips

Table 3.5 Particle size characteristics (geometric mean ± geometric standard deviation) for the products of the corresponding processes at the beginning and at the end of the percentage change. Treatment Day 0 Day 112 % Change WC 5.08 + 1.66 4.60 ± 1.87 -9.45 SS + WC 2.74 ± 2.80 4.11 ± 2.04 -33.33 SS + WC + EM 4.16 ± 2.09 2.33 ± 2.94 -43.99 SS + WC + e / w 4.26 ± 2.00 1.42 + 3.27 -66.67 SS + WC + EM + e / w 1.05 + 3.23 4.41 ± 1.91 -76.19` EM, inoculated with microorganisms; e / w earthworms; SS, sewage sludge; WC, wood chips
Day 0 refers to the initial mixing time of the waste before decomposition.

Table 4.1 The content of heavy metals in compost and in compost obtained using earthworms after 112 days (n = 9). Treatment Al (g 100 g ^-1 ) As (μg g ^-1 ) Cu (μg g ^-1 ) Ni (μg g ^-1 ) SS + WC 335.33 ± 19.91 <0.05 315.40 ± 51.56 551.33 ± 28.09 SS + WC + EM 223.67 + 79.98 <0.05 362.00 + 71.59 493.33 + 56.89 Significantly different (P <0.05) SS, sewage sludge; WC, wood chips; EM, seeded with microorganisms Table 4.2 The content of heavy metals in the tissues of earthworms before and after composting using earthworms (n = 9). Time (days) Al (g 100 g ^-1 ) As (μg g ^-1 ) Cu (μg g ^-1 ) Ni (μg g ^-1 ) Al (g 100 g ^-1 ) SS + WC 0 9.50 ± 3.94 ^a <0.05 ^a 84.95 ± 11.61 ^a 46.62 + 4.22 ^a SS + WC + EM 0 13.17 ± 4.58 ^a <0.05 ^a 97.15 ± 3.99 ^a 50.87 + 9.58 ^a SS + WC 94 33.83 ± 17.20 ^{* b} <0.05 ^{* a} 147.55 ± 14.67 ^s 89.97 + 7.56 ^{* b} SS + WC + EM 94 11.17 ± 5.46 ^a <0.05 ^a 105.33 ± 20.29 ^a 51.00 + 28.21 ^a Significantly different (P <0.05) from the initial content ^{a, b} - Average values with the same letter index did not differ significantly (P> 0.05) SS, sewage sludge; WC, wood chips; EM, seeded with microorganisms Table 4.3 PBC (an indicator of bioconcentration) in the tissues of earthworms after composting using earthworms for 84 days. Al (g 100 g ^-1 ) As (μg g ^-1 ) Cu (μg g ^-1 ) Ni (μg g ^-1 ) SS + WC 0.10 Nd 0.47 0.16 SS + WC + EM 0.05 Nd 0.29 0.10 ^{a, b} - Mean values with the same letter index did not differ significantly (P> 0.05) PBC = ^{[e / w]} / _[substrate] ND: Not detected; SS, sewage sludge; WC, wood chips; EM, seeded with microorganisms

Claims (20)

1. A method of processing the mass of a dump formed as a result of mining, including the step of introducing wood chips obtained from waste wood extracted from the wooden supports of the mine, destroyed during blasting, and which are a byproduct of mining, into the mass of the blade, by processing the mass of the blade with wood chips to a level of up to 30 cm below the outer surface. 2. The method according to claim 1, in which wood chips are pre-treated with acid. 3. The method according to claim 2, in which nitric acid (HNO ₃ ) is used as the acid. 4. The method according to any one of claims 1 to 3, in which wood chips are applied to the existing mass of the blade formed in the form of an embankment, to restore this embankment. 5. The method according to any one of claims 1 to 3, in which wood chips are introduced into the mass of the blade periodically during its formation. 6. The method according to any one of claims 1 to 3, in which wood chips are applied in an amount of 60-90 tons per hectare of surface of the tail dump. 7. The method according to any one of claims 1 to 3, which includes the step of composting wood chips, performed before the step of introducing chips into the mass of the blade. 8. The method according to claim 7, in which the step of composting wood chips includes the step of composting wood chips using earthworms. 9. The method of claim 8, wherein the step of composting the wood chips further comprises the step of mixing the chips with another source of organic material. 10. The method according to claim 9, in which waste water is used as another source of organic material. 11. The method according to claim 10, in which wood chips and wastewater are mixed and composted from them, after which the compost is seeded with worms and an environment composted using earthworms is formed, 12. The method according to claim 11, in which the worms are selected from a species of Eisenia fetida. 13. The method according to claim 11, in which wood chips and wastewater are mixed with a ratio of from 3: 1 to 3: 2. 14. The method according to any one of claims 1 to 3, which includes the step of planting selected plants on the treated mass of the blade. 15. The method according to 14, in which the plants are selected from the group consisting of Cenchrus ciliaris species Molopo; Cenchrus ciliaris species Gayndah; Eragrostis lehmanniana (Lehmann's love grass); and Eragrostis curvula and mixtures thereof. 16. The mass of the blade processed in accordance with the method according to any one of claims 1 to 15. 17. An environment for treating the mass of the blade resulting from mining by treating the mass of the blade with wood chips up to 30 cm below the outer surface of the blade, containing a composted mixture of wood chips obtained from waste wooden mine supports destroyed during blasting, and which are a byproduct of mining, and another source of organic material. 18. The environment of claim 17, wherein wastewater is used as another source of organic material. 19. The environment of claim 18, wherein the mixture is further composted using earthworms. 20. The medium according to claim 19, which further comprises in a certain way selected microorganisms.

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