The present work is an account of an ongoing work on biogas production from animal wastes at LEREA (Laboratoire d’enseignement et de recherche en énergétique appliquée) in Mamou, Guinea. The work consists of biogas production from anaerobic digestion and co-digestion of cow dung and droppings. We focus in this report on the determination of the physico-chemical characteristics of the experimental setup. We have carried out three experiments of anaerobic digestion each one lasting 45 days at mesophilic temperature (temperature was maintained in the range 27°C - 28°C). Biogas - 28.4 liters have been obtained from droppings, 22.6 liters from cow dung and 38.7 liters from co-digestion of the previous two wastes. The following physico-chemical characteristcs were observed for cow dung: humidity 43%, dry matter 20.83%, organic matter 57%, density 625kg/m3, carbon content 31%, nitrogen content 1.46%, nitrogen-carbon ratio 21/30. For droppings we measured: humidity 35%, dry matter 65%, organic matter 62%, density 250 kg/m3, carbon content 36%, nitrogen level 1.83%. This characterization was carried out on a sample of 3 g of each type of substrate. These results agree with those of the literature that we were able to compare with. Keywords: anaerobic digestion; anaerobic co-digestion; physico-chimical characterization; cow dung weste; droppings weste; methanation; animal waste

This study reveals the selection of a yeast strain, possessing inulinase activity and finding the optimal conditions of cultivation. Intra- and extracellular activity assay was performed after cultivation on media, containing inulin as a sole source of carbon. Optimization of the cultivation conditions was carried out for establishing the favorable conditions for biosynthesis of inulinase. Modifying the physicochemical and nutritional parameters of a cultivation process lead to major improvement of the enzyme activity. Highest intra- and extracellular inulinase activity was registered when 1.5% inulin was used, 5 % inoculum, temperature 28°C, pH=6.5 and agitation of 200rpm. The selected strain Kluyveromyces sp. C showed higher values for the intracellular inulinase activity, making it suitable for immobilization and further use. Key words: Kluyveromyces sp., inulinase activity, parameters optimization

The paper presents results of landscape planning and investigation on Fluvisols. The object is “Koriata” sand and gravel quarry, Bulgaria. Soil samples were taken from seventeen soil profiles at a depth of 0-20 cm, 20-40 cm, 40-60 cm, 60-80 cm, and 80-100 cm. There were significant correlations between the physical and chemical soil properties in 40 out of 48 cases. Statistically significant high correlation coefficients (> ±0.6) have been calculated: for example, there is a negative correlation between bulk density on the one hand and soil organic matter (SOM) and nutrients on the other; there is a high positive correlation between total porosity and SOM and nutrients. The correlations between the clay fraction and SOM, total Kjeldahl nitrogen (TKN) and K2O are also high. Formulating a landscape plan for the territory of “Koriata” sand and gravel quarry will improve the quality of life of residents, will result in at least a sevenfold increase in plant diversity and will meet the demand for themed waterparks within the city limits of Sofia.

In this paper a possibility of applying anaerobic digestion for reduction and stabilization of the organic fraction of solid wastes generated during piloted spacecraft flights is discussed.The culture of Trihoderma viridae, capable of utilizing cellulose-containing substrates under mesophilic conditions, was studied.The strain was isolated from the internal environment of the ISS.The main purpose of the work was to test the ability of Trihoderma viridae culture to consume the products of anaerobic decomposition of gauze tissue under space flight conditions, i.e. substrate for the cultivation of the fungus served as liquid media, formed after the decomposition of thermophilic clostridia gauze wipes.Under conditions of space flight, the culture of Trihoderma viridae reduced the total concentration of volatile organic impurities remaining after the biodegradation of gauze from 34 mg / m 3 to 5 mg / m 3 .The number of detectable volatile compounds decreased almost twice.The carried out researches have shown that the post-cleaning of liquid products of hydrolysis of gauze fabric with the help of cellulolytic fungi can be an effective component of utilization of cosmonaut hygiene items with the help of microbial communities in space flight conditions.Also under terrestrial conditions, the liquid products of biodegradation of plant wastes were further purified with the help of a community of aerobic bacteria.Chromatomass-spectrometric analysis showed that the consortium composed of aerobic mesophilic bacteria actively consumed products present in vegetable homogenates.

Microbial fuel cells (MFC) are an environmentally friendly way of generating electricity, which is often accompanied by the decomposition of organic waste. A common problem for these devices is the low power generated by the electric current. In nature, the decomposition of organic waste, coupled with oxidation-reduction reactions, i.e. the transfer of electrons and protons formed during the decomposition is carried out by microbial communities, which, in their optimal state for this process, are called active sludge (AS). A mature active sludge consists of a so-called flocculium - round formations in the size from 30 to 100 and more microns, inside of which microorganisms carrying out various reactions of decomposition of organic substances are contained. It is easy to see that the MFC design is topologically similar to the active sludge flocculant. We tried to check how the presence of microorganisms in the water chamber affects the productivity of the MFC by filling the anode and cathode chambers with the same sludge mixture, and the test cells were shaken on a shaker to create favorable conditions for the formation of microbial communities. The active sludge cell in both chambers shaken on the shaker, over time, generated the highest voltage in the external circuit as compared to the control samples. The obtained data confirm the legitimacy of the assimilation of MFC flocculine AS. The evolution of the microbial community of the silt mixture in two directions - in the aerobic and anaerobic MFC chambers - apparently leads to the formation of two different communities mutually complementing each other as part of the MFC and improving the operation of the MFC, subject to additional dynamic provision (shaking). The effect of the addition of peptone to the anode chamber on the productivity of MFC was also investigated. The periodic addition of peptone significantly increased the output power of the MFC cell. Apparently, substrates of protein nature, representing a nutrient medium for electrogenic bacteria, can be used to stimulate the electrogenic activity of the microflora of late anaerobic silt.

Marine ecosystems are under increasing anthropogenic pressures from marine and terrestrial activities. Shipping forms a network that spans the globe and introduces many economically and environmentally harmful invasive species, including human diseases such as cholera. Ship traffic, the major cause of change in the open ocean, and its temporal evolution are still largely unknown. Since the 1960s the Black Sea has undergone dramatic environmental changes. These changes are considered as result from a complex interaction of different pressures, the most important being eutrophication, overfishing and introduction of alien species. Some nations, and the International Maritime Organization, are moving towards requirements for managing ballast water to reduce the number of alien species transported and released.

39 mountains are situated on the territory of Bulgaria, 8 of which have peaks higher than 2000 m a.s.l. Mountain areas refer hypsometrically to territories above 600 m altitude (from 600 m up to 2925 m) with a total area of 30,608 km2 or 27.6% of the country. Within this range are situated the resources of forests, pastures, spring waters, game, mountain agriculture and livestock-breeding, as well as tourism and sport facilities. Some small towns, villages and hamlets in the mountains are however depopulated due to migration processes. Mountain forest resources are spread all over the following vegetation belts: 1. Carpinus betulus L.-Quercus petraea Liebl. belt, 2. Fagus sylvatica L. belt, 3. Coniferous forests belt, 4. Sub-alpine thin forests, Pinus mugo Turra and Juniperus sp. formations belt. The forests by-products include the returns of hay, foliage, forest fruits, different kind of nuts, lime-blossoms, medical herbs and mushrooms. The national parks, the bigger part of nature parks and reserves are distributed mainly in the mountains, where they preserve the biodiversity and the genetic resources of plants and animals. Mountain agriculture and livestock-breeding are directed to traditional bio-products and food security. Many monasteries, churches and mosques, as part of the cultural-historical heritage, are situated in mountain regions.

In this review, the dissemination of bacterial pathogens in natural waters and the mechanisms of their transmission in drinking water, and the role of water-associated biofilms for their survival or growth are discussed. The current state of the studies on biofilm-formation potential of the emerged pathogens in drinking water and the role of interspecies interactions for attachment and survival of pathogenic bacteria in the biofilm community is summarized. The contribution of the biofilms for increasing antimicrobial resistance of pathogens is discussed.

The paper proposes a methodology for developing information model or database of waste disposal sites /WDS/ or landfill sites, applying received remotely and in-situ data from Earth surface monitoring, especially including procedures of morphological processing, data normalization and visualization models. The overall structure and composition of the information model, described subsystems, classes, objects, and attributes (properties) of the data, are presented. The possibility of formation of new information relations, that arise between different kinds of information, through morphological (in particular, the morphemic) processing “raw” information at the input, for example, between the classifiers (waste products, settlements, economic activities, etc.), is described. The paper used methods of system analysis, methods of mathematical linguistics, space monitoring methods. For example a structure of constructing the database, the archive and the classifier of unauthorized waste disposal facilities (solid waste landfills, waste piles, municipal landfills, and others) is presented. The scheme of data model describes the components (tables) as part of the model: general information, geometric and geographic parameters of geo-referenced data, including data for adjacent territorial-administrative facilities, etc.

The presented paper proposes a method for estimating parameters and characteristics of the chemical processes in large municipal landfills and solid waste disposal sites according to the waste monitoring from space. The model of chemical transformations in the waste disposal sites is described based on the idea of waste biochemical degradation in the form of the “transformations tree”. The presentation of chemical transformations in the form of statistical integrated chemical equations allows us to describe the chemical system "a waste disposal facility" in the analytical form. The paper presents the main types of physical (volume and mass, thermal) and chemical (filtrate) characteristics which assessment could be made by data from satellite images. As an example the obtaining of the volume and mass characteristics of landfills in their 3D-models is described. Results of the algorithm on the example of a polygon of solid municipal and industrial waste in Salaryevo (Leninsky district of the Moscow region) are presented. As an example the assessment of volume and mass of landfill gas and its main component – methane is shown. An airborne image from year 2000 is compared with the satellite images in visible spectral range closed to its date. The main sources of errors in the evaluation of volume and mass characteristics are defined. The error which source is the spatial and spectral resolution of the satellite image is calculated.