International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Soil contamination with radionuclides poses a serious threat to the health of the population. It can occur in radioactive incidents and accidents and improper management of radioactive waste. The mobile and bioavailable forms of radioactive contaminants are critical in predicting their transfer through food chains. This study presents the influence of soil organic matter on the leaching of 241Am, 60Co and 137Cs by distilled water from soils, taken from six regions in Bulgaria. The experiment was carried out by Chromic Cambisol, Eutric Fluvisol, two Calcaric Chernozem soils, Gleyic Fluvisol and Vertisol, taken from the surface soil layer 0-10 cm. The initial soil samples did not contain radionuclides and were contaminated by radioactive solution in the laboratory. The soil organic matter was removed from aliquot of the samples by treatment with 6 % NaClO and heating at 96 oC. The investigation aimed to examine the water-soluble forms of the radionuclides in soils, containing aliquots with removed organic substances as well as in natural soils. The contaminated soils were stored at 18 oC and water extraction of the radionuclides was performed after 75 min and 3 weeks after radioactive pollution. The radioactivity of the samples was measured by gamma spectrometry. The results showed that removing soil organic matter has different effects on the watersoluble forms of radiocesium and radiocobalt. No changes in the water-soluble forms of americium were measured. Adding soil with removed organic matter to Calcaric Chernozem soil was found to be an efficient approach to decrease the water-soluble forms of 60Co in the first three weeks after contamination.

The present study uses the method of soil crops to study the fertilization of the soil, changes in the content and forms of nutrients, the effectiveness of various forms of nutrients introduced by the resulting of soil improver – a mixture of waste – wood ash and poultry litter, by means of a vegetation experiment. Sweet pepper Capsicum annuum subsp. macrocarpum L. was selected for the experiment, variety of gate type – Gold medal 7. The results of the study prove the ability to use soil improvers, good resistance of the leaves to sudden intense changes in climatic conditions. The root systems of all mixtures are well developed and strong, stable with good agrochemical parameters compared to that of the zero sample.

The present study examines the possibilities for reclamation of soils contaminated with heavy metals from the extraction of polymetallic ores with soil improvers mixture of waste – sludge from WWTP and ash from thermal power plants, through a vegetation experiment. Two herbaceous species of the genus Rumex were selected for the experiment – R. acetossela and R. patienta known for their ability to accumulate heavy metals and in particular copper. The results of the study prove the ability to use the improvers in biological reclamation of old embankments.

The basic radionuclides that cause natural radiation – potassium, uranium, radium, thorium, radon, thorom. Is described their content in different soils and rocks, as given more attention to potassium because it is the most widespread in the earth’s crust and its influence is strongest. An analysis of radiological monijoring of soils in Bulgaria in the past two years, which show that there is no deviation from the normal background values.

We offer a multi-functional operating element of rotary type for a channel cleaner, which is capable of performing the entire cycle of cleaning household water reservoirs (ponds), in particular:1. due to the compound rotor:1.1. mow and chop the crop;
2. due to the implementation of detachable body:2.1. mill and transport “dry” soils using a jet of air;2.2. pump water;2.3. extract and transport the soil from under the water;

3. due to the installation of the teeth on the lower movable part of the body:3.1. work as a clamp grapple to remove garbage from water reservoirs (ponds).

The basis of multifunctionality of this invention is in the principle of implementation of the maximum number of hidden abilities of the initial technical system, its rotor, framing, manipulator parts, which implies the subsequent creation of a reclamation robot.