IFIP Advances in Information and Communication Technology, 2019
The geological-geomorphological features of the river catchments control flood propagation by inf... more The geological-geomorphological features of the river catchments control flood propagation by influencing the surface runoff and its redistribution to surface and underground flow. The paper analyses the geological-geomorphological susceptibility to floods in a part of the river Struma valley – Municipalities Kresna and Strumyani (Bulgaria, EU). The following parameters are considered: lithology (presented by water permeability, capacity and type of rock reservoirs), distance from streams/river, slopes and fluvial landforms. Raster layers for each one of these parameters are created in geographic information system (GIS) environment and susceptibility rates are assigned. The flood susceptibility map is elaborated by spatial weighted sum overlay of the raster layers. The results show that the susceptibility is the highest in the low part of the valley, south of Kresna. The susceptibility of flooding is not equal over the whole area of the floodplain but depends on the retention capacity of the alluvial deposits and the hydro-geomorphological state of the floodplain. The river bank height above the water level and the river bed type are also taken into consideration by application of fuzzy logic. Using the fuzzy logic minimizes some imperfections of the initial data and gives good results in data-scarce areas. The fuzzy logic model is designed as a two-level hierarchical system with three inputs and one output. The output gives the complex assessment for geological-geomorphological flood susceptibility of study area regarding the interaction of the three inputs. The results of the current research aims to direct the attention of planning experts and decision-makers to the importance of geological-geomorphological parameters in flood management and can be considered as a first step of flood hazard assessment.
Natural hazards are existence of natural components and processes, which create a situation that ... more Natural hazards are existence of natural components and processes, which create a situation that could negatively affect people, the economy and the environment. Rising public awareness about natural hazards could improve the quality of life, save financial resources and even save lives. The complicated essence of natural hazards and the interrelations between natural components require a complex analysis of natural hazard factors. In the current research, the factors are analysed by application of analytic hierarchy process. Spatial overlay analysis is done in GIS environment and as a result, landslide susceptibility and flood susceptibility maps are created. Single hazard maps are overlaid in order to receive a complex hazard level. A fuzzy logic with four inputs and one output is designed. This model is used to determine the complex level of hazard considering the factors interaction. The results of the current research and suggested approach could support decision makers in civi...
Current Research Topics in Applied Microbiology and Microbial Biotechnology, 2009
ABSTRACT The microbial strains used for decontamination of different origin wastewater should not... more ABSTRACT The microbial strains used for decontamination of different origin wastewater should not only be highly active to one of the contaminants but they should also be resistant enough to the remainder. Their resistance can be ensured by the degradation activity of the strains used towards most of the waste products present in the wastewater. Trichosporon cutaneum R57 is known as an effective biodegradant able to utilize and thus remove a number of toxic aromatic compounds from the environment. The present paper deals with processes of degradation and utilization of monohydroxyl derivatives of phenol (resorcinol, catechol and hydroquinone), as well as some of the most toxic aromatic pollutants of the environment like 2,6 - dinitrophenol, alpha-methylstyrene and acetophenone. The basic kinetic parameters for the biodegradation of the listed above compounds are reported. The highest initial concentrations which could be degraded by the investigated strain were as follow: resorcinol - 1.6 g/l; catechol - 1.3 g/l; hydroquinone - 1.2 g/l; 2,6-dinitrophenol -0.7 g/l; alpha-methylstyrene and acetophenone - 0.5 g/l. The inhibition coefficients were Calculated according to the Haldane-kinetics. The results obtained certainly proved the ability of strain T. cutaneum R57 to degrade wide range toxic contaminants present in industrial production wastewaters.
Journal of Industrial Microbiology & Biotechnology, 2008
Most industrial wastes contain different organic mixtures, making important the investigation on ... more Most industrial wastes contain different organic mixtures, making important the investigation on the microbial destruction of composite substrates. The capability of microbes to remove harmful chemicals from polluted environments strongly depends on the presence of other carbon and energy substrates. The effect of mixtures of phenol- and methyl-substituted phenols (o-, m-, p-cresol) on the growth behaviour and degradation capacity of Trichosporon cutaneum strain was investigated. The cell-free supernatants were analysed by HPLC. It was established that the presence of o-, m- and p- cresol has not prevented complete phenol assimilation but had significant delaying effect on the phenol degradation dynamics. The mutual influence of phenol and p-cresol was investigated. We developed the kinetic model on the basis of Haldane kinetics, which used model parameters from single-substrate experiments to predict the outcome of the two-substrate mixture experiment. The interaction coefficients indicating the degree to which phenol affects the biodegradation of p-cresol and vice versa were estimated. Quantitative estimation of interaction parameters is essential to facilitate the application of single or mixed cultures to the bio-treatment of hazardous compounds.
The ability of the white rot fungus Trametes versicolor strain 1 to degrade and utilize methylate... more The ability of the white rot fungus Trametes versicolor strain 1 to degrade and utilize methylated phenols (cresols) was established for the first time in a medium not containing any other carbon components. The data obtained demonstrated the better potential of the strain to assimilate p-cresol instead of o- or m- cresol. The 0.5 g/l p-cresol provided was degraded in full after 96 h. The effect of a dual substrate mixture (0.3 g/l phenol + 0.2 g/l p-cresol) on the growth behavior and degradation capacity of the investigated strain was examined. The cell-free supernatants were analyzed by HPLC. It was established that the presence of p-cresol had not prevented complete phenol degradation but had a significant delaying effect on the phenol degradation dynamics. Phenol hydroxylase, catechol 1.2-dioxygenase and cis,cis-muconate cyclase activities were obtained in conditions of single and mixed substrates cultivation. The influence of different phenolic substrates on phenol hydroxylase activity in Trametes versicolor 1 was established. The mathematical models describing the dynamics of single substrates' utilization as well as the mutual influence of phenol and p-cresol in the mixture were developed on the bases of Haldane kinetics. The estimated interaction coefficients (I(ph/cr) = 4.72, I(cr/ph) = 7.46) demonstrated the significant inhibition of p-cresol on phenol biodegradation and comparatively low level of influence of phenol presence on the p-cresol degradation. Molecular 18S RNA gene taxonomy of the investigated strain was performed.
Keywords: Mathematical modeling, Acidithiobacillus ferrooxidans , ferric ions Acidithiobacillus f... more Keywords: Mathematical modeling, Acidithiobacillus ferrooxidans , ferric ions Acidithiobacillus ferrooxidans oxidizes ferrous ions and are used for waste water and tail gas treatment. The application of bacteria in environmentally friendly technologies may fall in surroundings with high concentrations of iron and lead, because these conditions are toxic for the strain. In order to avoid inhibition of the bacterial action, it is necessary to adapt Acidithiobacillus ferrooxidans to high initial concentrations of iron ions. There are scarce literature data for mathematical models of periodic cultivation of this strain. The mathematical model would give a better idea about the processes that take place during adaptation of the strain to higher initial concentrations of substrate.,The purpose of this work is to present the mathematical model describing the first two phases of the batch. Mathematical modeling was based on Haldane model that takes into account sigmoid nature of the depende...
Acidithiobacillus ferrooxidans is among the few microorganisms which take energy from the oxidati... more Acidithiobacillus ferrooxidans is among the few microorganisms which take energy from the oxidation of the ferrous ions in acidic medium. That hemolitoautotrophic bacterium is well known and successfully used in the wastewater treatment of and in all aspects of microbial mediated extraction of metals from minerals or solid wastes and acid mine drainages. The use of bacteria in environmentally friendly technologies may fall in areas with high concentrations of iron and lead, and this is toxic for the strain. In order to avoid inhibition of the bacterial action, it is necessary to adapt Acidithiobacillus ferrooxidans to high initial concentrations of iron ions. The aim of present work is to estimate the processes of substrate oxidation and cells growth in exponential phase of batch cultivation of the strain, loaded higher initial concentration of ferric ions. It was established that there is no in uence of initial substrate concentrations on the strain in the beginning stages of it...
Acidithioacillus ferrooxidans is an autotrophic, acidophilic, mesophile occurring in single or oc... more Acidithioacillus ferrooxidans is an autotrophic, acidophilic, mesophile occurring in single or occasionally in pairs or chains, depending on growth conditions. Among the group of Acidithiobacillus, A. ferrooxidans has emerged as an economically significant bacterium in the field of leaching of sulfide ores. The discovery of A. ferrooxidans leds to the development of a new branch of metallurgical sciences called "biohydrometallurgy," which deals with all aspects of microbial mediated extraction of metals from minerals or solid wastes and acid mine drainage. This work is a part of studies on the bacterial physiology in regimes of cultivation in media with high substrate concentrations. It aims to evaluate with statistical significance similarity, or differences in biomass experimental curves. Three series of experiments were elaborated for studying the influence of high concentrations of ferrous ions. The bacterial growth was studied by samples, taken from the cultural media...
The soil erosion is considered as one of the most serious environmental problem in a global scale... more The soil erosion is considered as one of the most serious environmental problem in a global scale. The development of the process could have negative impact on water, vegetation and ecosystem as a hole, as well as to influence on the quality of life. If the process is not mitigated in long term it could change the topographic surface and to trigger geomorphological hazards. The researches on soil erosion require analyses of large volume of information about soil properties, topographic surface, precipitation and land use. In the current research GIS technology is used for building the data base, spatial analyses and visualization of the results. The Universal Soil Loss Equation (USLE) is applied in Map Algebra and spatial distribution of soil loss is presented. The results are considered in relation to land use, particularly arable lands and vineyards. The application of computer technology provide opportunities for easy processing of data and updating the model by adding new data w...
Microorganisms are dominant form of life on the Earth. It is necessary to enlarge the knowledge a... more Microorganisms are dominant form of life on the Earth. It is necessary to enlarge the knowledge about them for more efficient use in all areas of biotechnology, medicine, ecology. Acidithiobacillus ferrooxidans are acidophilic chemolitoautothropfic bacteria, with capability to oxidize ferrous ions and used in waste water, tail gas treatment and bioleaching technologies. In appropriate conditions it forms solid biofilm structures with high efficiency. Every biofilm starts from suspended culture and it is important to know about activity of suspended cells. This work aims to study on the oxidation dynamics of Fe by Acidithiobacillus ferrooxidans at initial stages of adaptation to high substrate concentrations. The dynamics of substrate degradation and accumulation of the product in terms of periodic cultivation of suspended cell culture have been studied. The oxidative degree and oxidative ratio are calculated. The obtained experimental results show stability in the strains behavior a...
IFIP Advances in Information and Communication Technology, 2019
The geological-geomorphological features of the river catchments control flood propagation by inf... more The geological-geomorphological features of the river catchments control flood propagation by influencing the surface runoff and its redistribution to surface and underground flow. The paper analyses the geological-geomorphological susceptibility to floods in a part of the river Struma valley – Municipalities Kresna and Strumyani (Bulgaria, EU). The following parameters are considered: lithology (presented by water permeability, capacity and type of rock reservoirs), distance from streams/river, slopes and fluvial landforms. Raster layers for each one of these parameters are created in geographic information system (GIS) environment and susceptibility rates are assigned. The flood susceptibility map is elaborated by spatial weighted sum overlay of the raster layers. The results show that the susceptibility is the highest in the low part of the valley, south of Kresna. The susceptibility of flooding is not equal over the whole area of the floodplain but depends on the retention capacity of the alluvial deposits and the hydro-geomorphological state of the floodplain. The river bank height above the water level and the river bed type are also taken into consideration by application of fuzzy logic. Using the fuzzy logic minimizes some imperfections of the initial data and gives good results in data-scarce areas. The fuzzy logic model is designed as a two-level hierarchical system with three inputs and one output. The output gives the complex assessment for geological-geomorphological flood susceptibility of study area regarding the interaction of the three inputs. The results of the current research aims to direct the attention of planning experts and decision-makers to the importance of geological-geomorphological parameters in flood management and can be considered as a first step of flood hazard assessment.
Natural hazards are existence of natural components and processes, which create a situation that ... more Natural hazards are existence of natural components and processes, which create a situation that could negatively affect people, the economy and the environment. Rising public awareness about natural hazards could improve the quality of life, save financial resources and even save lives. The complicated essence of natural hazards and the interrelations between natural components require a complex analysis of natural hazard factors. In the current research, the factors are analysed by application of analytic hierarchy process. Spatial overlay analysis is done in GIS environment and as a result, landslide susceptibility and flood susceptibility maps are created. Single hazard maps are overlaid in order to receive a complex hazard level. A fuzzy logic with four inputs and one output is designed. This model is used to determine the complex level of hazard considering the factors interaction. The results of the current research and suggested approach could support decision makers in civi...
Current Research Topics in Applied Microbiology and Microbial Biotechnology, 2009
ABSTRACT The microbial strains used for decontamination of different origin wastewater should not... more ABSTRACT The microbial strains used for decontamination of different origin wastewater should not only be highly active to one of the contaminants but they should also be resistant enough to the remainder. Their resistance can be ensured by the degradation activity of the strains used towards most of the waste products present in the wastewater. Trichosporon cutaneum R57 is known as an effective biodegradant able to utilize and thus remove a number of toxic aromatic compounds from the environment. The present paper deals with processes of degradation and utilization of monohydroxyl derivatives of phenol (resorcinol, catechol and hydroquinone), as well as some of the most toxic aromatic pollutants of the environment like 2,6 - dinitrophenol, alpha-methylstyrene and acetophenone. The basic kinetic parameters for the biodegradation of the listed above compounds are reported. The highest initial concentrations which could be degraded by the investigated strain were as follow: resorcinol - 1.6 g/l; catechol - 1.3 g/l; hydroquinone - 1.2 g/l; 2,6-dinitrophenol -0.7 g/l; alpha-methylstyrene and acetophenone - 0.5 g/l. The inhibition coefficients were Calculated according to the Haldane-kinetics. The results obtained certainly proved the ability of strain T. cutaneum R57 to degrade wide range toxic contaminants present in industrial production wastewaters.
Journal of Industrial Microbiology & Biotechnology, 2008
Most industrial wastes contain different organic mixtures, making important the investigation on ... more Most industrial wastes contain different organic mixtures, making important the investigation on the microbial destruction of composite substrates. The capability of microbes to remove harmful chemicals from polluted environments strongly depends on the presence of other carbon and energy substrates. The effect of mixtures of phenol- and methyl-substituted phenols (o-, m-, p-cresol) on the growth behaviour and degradation capacity of Trichosporon cutaneum strain was investigated. The cell-free supernatants were analysed by HPLC. It was established that the presence of o-, m- and p- cresol has not prevented complete phenol assimilation but had significant delaying effect on the phenol degradation dynamics. The mutual influence of phenol and p-cresol was investigated. We developed the kinetic model on the basis of Haldane kinetics, which used model parameters from single-substrate experiments to predict the outcome of the two-substrate mixture experiment. The interaction coefficients indicating the degree to which phenol affects the biodegradation of p-cresol and vice versa were estimated. Quantitative estimation of interaction parameters is essential to facilitate the application of single or mixed cultures to the bio-treatment of hazardous compounds.
The ability of the white rot fungus Trametes versicolor strain 1 to degrade and utilize methylate... more The ability of the white rot fungus Trametes versicolor strain 1 to degrade and utilize methylated phenols (cresols) was established for the first time in a medium not containing any other carbon components. The data obtained demonstrated the better potential of the strain to assimilate p-cresol instead of o- or m- cresol. The 0.5 g/l p-cresol provided was degraded in full after 96 h. The effect of a dual substrate mixture (0.3 g/l phenol + 0.2 g/l p-cresol) on the growth behavior and degradation capacity of the investigated strain was examined. The cell-free supernatants were analyzed by HPLC. It was established that the presence of p-cresol had not prevented complete phenol degradation but had a significant delaying effect on the phenol degradation dynamics. Phenol hydroxylase, catechol 1.2-dioxygenase and cis,cis-muconate cyclase activities were obtained in conditions of single and mixed substrates cultivation. The influence of different phenolic substrates on phenol hydroxylase activity in Trametes versicolor 1 was established. The mathematical models describing the dynamics of single substrates' utilization as well as the mutual influence of phenol and p-cresol in the mixture were developed on the bases of Haldane kinetics. The estimated interaction coefficients (I(ph/cr) = 4.72, I(cr/ph) = 7.46) demonstrated the significant inhibition of p-cresol on phenol biodegradation and comparatively low level of influence of phenol presence on the p-cresol degradation. Molecular 18S RNA gene taxonomy of the investigated strain was performed.
Keywords: Mathematical modeling, Acidithiobacillus ferrooxidans , ferric ions Acidithiobacillus f... more Keywords: Mathematical modeling, Acidithiobacillus ferrooxidans , ferric ions Acidithiobacillus ferrooxidans oxidizes ferrous ions and are used for waste water and tail gas treatment. The application of bacteria in environmentally friendly technologies may fall in surroundings with high concentrations of iron and lead, because these conditions are toxic for the strain. In order to avoid inhibition of the bacterial action, it is necessary to adapt Acidithiobacillus ferrooxidans to high initial concentrations of iron ions. There are scarce literature data for mathematical models of periodic cultivation of this strain. The mathematical model would give a better idea about the processes that take place during adaptation of the strain to higher initial concentrations of substrate.,The purpose of this work is to present the mathematical model describing the first two phases of the batch. Mathematical modeling was based on Haldane model that takes into account sigmoid nature of the depende...
Acidithiobacillus ferrooxidans is among the few microorganisms which take energy from the oxidati... more Acidithiobacillus ferrooxidans is among the few microorganisms which take energy from the oxidation of the ferrous ions in acidic medium. That hemolitoautotrophic bacterium is well known and successfully used in the wastewater treatment of and in all aspects of microbial mediated extraction of metals from minerals or solid wastes and acid mine drainages. The use of bacteria in environmentally friendly technologies may fall in areas with high concentrations of iron and lead, and this is toxic for the strain. In order to avoid inhibition of the bacterial action, it is necessary to adapt Acidithiobacillus ferrooxidans to high initial concentrations of iron ions. The aim of present work is to estimate the processes of substrate oxidation and cells growth in exponential phase of batch cultivation of the strain, loaded higher initial concentration of ferric ions. It was established that there is no in uence of initial substrate concentrations on the strain in the beginning stages of it...
Acidithioacillus ferrooxidans is an autotrophic, acidophilic, mesophile occurring in single or oc... more Acidithioacillus ferrooxidans is an autotrophic, acidophilic, mesophile occurring in single or occasionally in pairs or chains, depending on growth conditions. Among the group of Acidithiobacillus, A. ferrooxidans has emerged as an economically significant bacterium in the field of leaching of sulfide ores. The discovery of A. ferrooxidans leds to the development of a new branch of metallurgical sciences called "biohydrometallurgy," which deals with all aspects of microbial mediated extraction of metals from minerals or solid wastes and acid mine drainage. This work is a part of studies on the bacterial physiology in regimes of cultivation in media with high substrate concentrations. It aims to evaluate with statistical significance similarity, or differences in biomass experimental curves. Three series of experiments were elaborated for studying the influence of high concentrations of ferrous ions. The bacterial growth was studied by samples, taken from the cultural media...
The soil erosion is considered as one of the most serious environmental problem in a global scale... more The soil erosion is considered as one of the most serious environmental problem in a global scale. The development of the process could have negative impact on water, vegetation and ecosystem as a hole, as well as to influence on the quality of life. If the process is not mitigated in long term it could change the topographic surface and to trigger geomorphological hazards. The researches on soil erosion require analyses of large volume of information about soil properties, topographic surface, precipitation and land use. In the current research GIS technology is used for building the data base, spatial analyses and visualization of the results. The Universal Soil Loss Equation (USLE) is applied in Map Algebra and spatial distribution of soil loss is presented. The results are considered in relation to land use, particularly arable lands and vineyards. The application of computer technology provide opportunities for easy processing of data and updating the model by adding new data w...
Microorganisms are dominant form of life on the Earth. It is necessary to enlarge the knowledge a... more Microorganisms are dominant form of life on the Earth. It is necessary to enlarge the knowledge about them for more efficient use in all areas of biotechnology, medicine, ecology. Acidithiobacillus ferrooxidans are acidophilic chemolitoautothropfic bacteria, with capability to oxidize ferrous ions and used in waste water, tail gas treatment and bioleaching technologies. In appropriate conditions it forms solid biofilm structures with high efficiency. Every biofilm starts from suspended culture and it is important to know about activity of suspended cells. This work aims to study on the oxidation dynamics of Fe by Acidithiobacillus ferrooxidans at initial stages of adaptation to high substrate concentrations. The dynamics of substrate degradation and accumulation of the product in terms of periodic cultivation of suspended cell culture have been studied. The oxidative degree and oxidative ratio are calculated. The obtained experimental results show stability in the strains behavior a...
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Papers by Plamena Zlateva