The initial part summarizes current knowledge about impact of pesticides on microorganisms and their activity. It also deals with a description and effects of organic fertilization used in the experiment (compost and composted biochar). Based on the literature, we determined the hypothesis: Pesticides have negative effect on soil microbial activity, which was tested in the experimental part. In the experimental part, we carried out a pot experiment. We made two basic versions: a control soil without pesticides and a soil after the application of pesticides. We growed specimens of lettuce (Lactuca sativa) in pots. One version was without organic fertilization, next with amended compost and the last one with composted biochar. In total, we prepared six variants of pots, which were subjected to various measurements. We determined the production of aboveground and underground biomass and the root/shoot ratio. This measurement showed that the variants with pesticides are more suitable for plant growth, plants were bigger in both, aboveground and underground biomass, so they can probably uptake nutrients from soil degraded by pollutants, which can´t hold them back. We also monitored activity of microbial respiration by two methods: by measuring the absorbance of CO2 at soda lime and by the substrate induced respiration. The results showed a decrease in respiration of microorganisms in polluted soil in both of these measurements. Results of mineral nitrogen leaching suprisingly determined, that less nitrogen escaped in soil with pesticides in both forms, amonnia and nitrate, but its amount was generally very low. Cellulose test showed worse total breakdown of cellulose in contaminated variants. Phytotoxicity test revealed, that pesticides may have inhibiting effect on plant germination, but the active substances of pesticides can stimulate growth and development of plant sprouts.

Diploma thesis presents the issue of the impact of the addition of charred plant biomass for vermicomposting. The theoretical section describes the definition of biochar, its production, and application benefits to the soil, and other purposes. In other section, devoted to vermicomposting, there is defined the methodology of domestic vermicomposting. The chapter which is devoted to the own experiment is based on the hypothesis that biochar slows down the process of vermicomposting, reduces odor and emissions produced during the process, and that the combination biochar with vermicompost would be a suitable alternative fertilizer. During the experiment, two bins for vermicomposting were used. Biodegradable waste and biochar were added to the first one, and biodegradable waste were added to the second one. The same type and amount of substrate were added to the bins, and they were placed under certain conditions. The difference was only in the addition of biochar. During the whole process, vermicomposting diversity and the resulting product were studied. Vermicompost was evaluated by the available methods.

The aim of this diploma thesis is to assess the ecotoxicological effect of biochar produced from sewage sludge. In case of application of biochar to agricultural land, both the soil and aquatic ecosystem may be affected therefore contact and aquatic tests were chosen to assess the ecotoxicological effects. Representatives of soil invertebrates were earthworms Eisenia fetida; Daphnia magna and Artemia salina were chosen from aquatic animals and terrestrial plants were represented by Lactuca sativa, Sinapis alba and Allium cepa. The results of contact tests point out how ecosystem could be negatively affected by biochar dose. Through aqueous extract were shown differences in sensitivity of individual organisms in aquatic tests. Dried sewage sludge was found to be the biggest burden for all tested organisms. The pelletized biochar with the addition of an additive showed the lowest negative effect on tested organisms.

This master's thesis deals with the analysis of biochar extracts by separation methods. All analyzed biochar was produced from waterworks sludge by microwave pyrolysis. The aim of the thesis is the optimization of the sample preparation method and its analysis in a laboratory environment. With the ever-growing world population, the problem of a sustainable economy in both agriculture and waste management is becoming increasingly urgent. This fact has led most countries to consider promoting the so-called Circular Economy. The use of sewage sludge as a feedstock for biochar production is perfectly in line with this strategy. So far, however, the short term and the long term benefits and risks of using biochar have not been sufficiently described. Potentially hazardous organic substances were extracted from the biochar extracts by three techniques: liquid-liquid extraction, solid-phase extraction, and solid- phase micro-extraction. The obtained samples were analyzed using the GS-MS/TOF method. The individual methods were compared. Several biochar samples from WWTP Brno and WWTP Drahovice were selected and analyzed to verify the suitability of the selected sample analysis method.

At present, the extraction of biochar and its use is a much-discussed topic in the chemical and research fields. The use of biochar is very often declined in the areas of agriculture, waste management, environmental improvement and the fight against global warming. In addition to these sectors, the topic of biochar is also addressed in the production of bio-diesel and bio-oil. Due to the current use of secondary products during biotechnological processes, the presented theoretical and practical study focused on the issue of obtaining biochar from bran by pyrolysis at different temperatures. Part of the practical part was the extraction of biochar from bran and its subsequent analysis, which could be used to characterize biochar obtained from bran by pyrolysis physically and chemically. The characterization of bran biochar was solved by various analytical methods. These techniques yielded, for example, pH, conductivity, particle distribution, elemental composition of biochar, porosity and content of polycyclic aromatic hydrocarbons. Thanks to this study, the properties of biochar and its possible applications in everyday life were characterized in detail. Given the very promising use of biochar obtained from bran, it can be said that this will be a very desirable topic for the future.

Biochar is created during the pyrolysis of organic biomass. Once added into the soil, it can improve its features. Biochars made from sewage sludge have various compositions. It is because of the vast difference between entrance materials. Organic pollutants can be absorbed into its surface during the cooling proces sof pyrolysis. If released into the enviroment, these compounds can cause inhibition of plant growth, get into food chains and adversely affect living organisms. Organic pollutans are determined most often by GC/MS after organic solvent extraction.

The thesis is focused on a determination of polycyclic aromatic hydrocarbons (PAHs) contained in dried pelletized sewage sludge and pelletized biochar. Biochars were made in mild conditions by microwave torrefaction of prepared sewage sludge. There were analyzed and quantified the 34 of standardized PAHs compounds in two series. The first serie, also called “Sada 1”, has been aimed at comparison of extraction methods for the chosen sample of sewage sludge and the sample of biochar. In serie “Sada 1”, there were compared efficiencies of chosen type of solvent or solvent mixture by comparison of yields for 34 standardized analytes in a sample of biochar and a sample of sewage sludge. There were compared also to total yields of PAHs and to number of quantified compounds in analyzed samples. The most reliable extraction method has been used for the next analyses of samples in the second serie called “Sada 2”. In Sada 2, there were compared different samples of the same type (e.g. biochar, sludge). The origin of sewage sludge (small or big sewage treatment plant expressed as PE) and used additives (cellulose, chaff, hay) as modificators for torrefaction process were variables for different type of sample. The results of analysis were identification of the most suitable sewage sludge and additive to be used as modificator for microwave torrefaction process. The main goal of correctly chosen sludge and additive was to minimize production of PAH’s during torrefaction and in samples of biochar.

This master's thesis deals with the analysis of organic substances, which are present in biochar. Biochar contains a number of organic compounds, that can be toxic and also carcinogenic to living organisms. In order for biochar to be used to improve soil quality or to be used for other applications, its safety must be declared by European or international certifications. Relevant European and international standards have been created for the determination of organic substances, that could be present in biochar. The theoretical part of the thesis was focused on selected organic substances, the process of pyrolysis and thermochemolysis, biochar characterisation and the used analytical methods. The experimental part of the thesis consisted of extraction with toluene and after that the determination of concentration of the 38 polycyclic aromatic hydrocarbons was performed. Qualitative analysis was performed by two-dimensional gas chromatography. Biochar samples were also subjected to thermochemolysis method and then they were analysed on GC-MS again. In both analytical methods, a large number of substances from groups such as PAHs, carboxylic acids, amines, substituted naphthalenes etc. was found, as well as smaller number of eg. polychlorinated biphenyls.