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The sustainable disposal of high-moisture municipal sludge (MS) has received increasing attention. Thermochemical conversion technologies can be used to recycle MS into liquid/gas bio-fuel and value-added solid products. In this review, we compared energy recovery potential of common thermochemical technologies (i.e., incineration, pyrolysis, hydrothermal conversion) for MS disposal via statistical methods, which indicated that hydrothermal conversion had a great potential in achieving energy recovery from MS. The application of machine learning (ML) in MS recycling was discussed to decipher complex relationships among MS components, process parameters and physicochemical reactions. Comprehensive ML models should be developed considering successive reaction processes of thermochemical conversion in future studies. Furthermore, challenges and prospects were proposed to improve effectiveness of ML for energizing thermochemical conversion of MS regarding data collection and preprocessing, model optimization and interpretability. This review sheds light on mechanism exploration of MS thermochemical recycling by ML, and provide practical guidance for MS recycling. © 2023 Elsevier Ltd

In the context of advocating carbon neutrality, there are new requirements for sustainable management of municipal sludge (MS). Hydrothermal carbonization (HTC) is a promising technology to deal with high-moisture MS considering its low energy consumption (without drying pretreatment) and value-added products (i.e., hydrochar). This study applied machine learning (ML) methods to conduct a holistic assessment with higher heating value (HHV) of hydrochar, carbon recovery (CR), and energy recovery (ER) as model targets, yielding accurate prediction models with R2 of 0.983, 0.844 and 0.858, respectively. Furthermore, MS properties showed positive (e.g., carbon content, HHV) and negative (e.g., ash content, O/C, and N/C) influences on the hydrochar HHV. By comparison, HTC parameters play a critical role for CR (51.7%) and ER (52.5%) prediction. The primary sludge was an optimal HTC feedstock while anaerobic digestion sludge had the lowest potential. This study provided a comprehensive reference for sustainable MS treatment and industrial application.

In order to realize the harmless treatment and resource utilization of municipal sludge, the effect of volatile-char interaction on the properties of sludge pyrolysis products was investigated using a two-stage pyrolysis reactor. The experimental results show that volatile-char interaction promotes the decomposition of organic compounds into small molecular gases, which increases the gas yield and reduces the liquid and oil yields. Under the experimental conditions, the volatile-char interaction increases the mass yields of H2, CO and CO2 to varying degrees, and the yield of H2 increases maximum by 55.7–114.5% compared to that without interaction. The effect of interaction on the composition of bio-oil occurs mainly at low temperature range of 400–600 ℃ by reducing the content of oxygen-containing compounds except for aldehydes/ketones. The physical and chemical structure of solid char changes dramatically with the interaction. The enhanced removal of O-containing groups occurs and the degree of aromaticity of the char is increased due to the strengthened dehydrogenation and polycondensation of hydrocarbons. Meanwhile, the transformation of non-hydroxyapatite phosphorus to hydroxyapatite phosphorus in solid phase products is greatly promoted at high temperature of 700–800 ℃, increasing the potential utilization of char as carbon-based phosphate fertilizer in agriculture.

Sewage sludge management and treatment can represent up to approximately 30% of the overall operational costs of a wastewater treatment plant. Microwave (MW) drying has been recognized as a feasible technology for sludge treatment. However, MW drying systems exhibit high energy expenditures due to: (i) unnecessary heating of the cavity and other components of the system, (ii) ineffective extraction of the condensate from the irradiation cavity, and (iii) an inefficient use of the microwave energy, among others issues. This study investigated the performance of a novel pilot-scale MW system for sludge drying, specifically designed addressing the shortcomings previously described. The performance of the system was assessed drying municipal centrifuged wasted activated sludge at MW output powers from 1 to 6 kW and evaluating the system's drying rates and exposure times, specific energy outputs, MW generation efficiencies, overall energy efficiencies, and specific energy consumption. The results indicated that MW drying significantly extends the duration of the constant rate drying period associated with the evaporation of the unbound sludge water, a phase associated with low energy input requirement for evaporating water. Moreover, the higher the MW output power, the higher the sludge power absorption density, and the MW generation efficiency. MW generation efficiencies of up to 70% were reported. The higher the power absorption density, the lower the chances for energy losses in the form of reflected power and/or energy dissipated into the MW system. Specific energy consumptions as low as 2.6 MJ L−1 (0.74 kWh L−1) could be achieved, well in the range of conventional thermal dryers. The results obtained in this research provide sufficient evidence to conclude that the modifications introduced to the novel pilot-scale MW system mitigated the shortcomings of existing MW systems, and that the technology has great potential to effectively and effic, BT/Environmental Biotechnology

Sewage sludge management and treatment can represent up to approximately 30% of the overall operational costs of a wastewater treatment plant. Microwave (MW) drying has been recognized as a feasible technology for sludge treatment. However, MW drying systems exhibit high energy expenditures due to: (i) unnecessary heating of the cavity and other components of the system, (ii) ineffective extraction of the condensate from the irradiation cavity, and (iii) an inefficient use of the microwave energy, among others issues. This study investigated the performance of a novel pilot-scale MW system for sludge drying, specifically designed addressing the shortcomings previously described. The performance of the system was assessed drying municipal centrifuged wasted activated sludge at MW output powers from 1 to 6 kW and evaluating the system's drying rates and exposure times, specific energy outputs, MW generation efficiencies, overall energy efficiencies, and specific energy consumption. The results indicated that MW drying significantly extends the duration of the constant rate drying period associated with the evaporation of the unbound sludge water, a phase associated with low energy input requirement for evaporating water. Moreover, the higher the MW output power, the higher the sludge power absorption density, and the MW generation efficiency. MW generation efficiencies of up to 70% were reported. The higher the power absorption density, the lower the chances for energy losses in the form of reflected power and/or energy dissipated into the MW system. Specific energy consumptions as low as 2.6 MJ L−1 (0.74 kWh L−1) could be achieved, well in the range of conventional thermal dryers. The results obtained in this research provide sufficient evidence to conclude that the modifications introduced to the novel pilot-scale MW system mitigated the shortcomings of existing MW systems, and that the technology has great potential to effectively and effic, BT/Environmental Biotechnology

Electrodewatering consists on the application of both pressure (mechanical effect) and electrical current (electrokinetic phenomena) to colloidal systems, such as municipal sludge, in order to achieve higher solid content (also designated by dryness). The influence of metal cations and its salts on the electrodewatering characteristics was systematically studied for municipal sludge and for two potential synthetic sludges, one composed of kaolin and the other of kaolin plus xanthan gum. The effect of the size, charge and concentration of the metal cations were studied in the three types of sludge. The effect of pH was also briefly addressed. The results were explained by the selective adsorption of metal cations to the surface of the dispersed particles. The adsorption was studied by ICP-AES (Inductively Coupled Plasma with Atomic Emission Spectrometer) metal analysis. This project was performed in collaboration with Ovivo. The first type of synthetic sludge was prepared by mixing kaolin powder with an electrolyte, where the nature of the salt and its concentration (from 0.0 to 0.2 M) were varied. In the presence of deionized water, the dryness of the sludge increases by 20%, from 62 to 74%. In general, the addition of salts of monovalent cations, such as MCl, where M=Li⁺, Na⁺, K⁺ and Rb⁺, causes an increase of the amount of water extracted from the sludge as long as the salt concentration is below 0.1 M. In the case of CsCl, the amount of water extracted decreases constantly with an increase in concentration. At the same concentration, the volume of water extracted is highest for cations with the largest hydrated radius: Li⁺> Na⁺ > K⁺ > Rb⁺ > Cs⁺. This series represents the opposite trend observed for the relative adsorption affinity of cations for the surface of the kaolin: Li⁺ < Na⁺ < K⁺ < Rb⁺ < Cs⁺. Therefore, electrodewatering is favored in the presence of poorly adsorbed metal cations as a direct result of improvement of the electromigration. M

QC 20101116

Biodegradable thermoplastics, polyhydroxyalkanoares (PHAs), were produced from municipal sludge in a two-stage bioprocess; anaerobic digestion of sludge by thermophilic bacteria in the first stage and production of PHAs from soluble organic compounds in the supernatant of digested sludge by Alcaligenes eutrophus in the second stage. Local municipal sludge of 0.3-5 wt \% dry solids containing 50-70\% volatile solids was digested under thermophilic (50-65 degrees C) and anaerobic conditions producing a mixture of fatty acids and other minor fermentation products. The residual sludge contains about 50\% of the original volatile solids. Volatile solids reduction and formation of soluble organic compounds from sludge were investigated under different temperature, pH, hydraulic (solid) retention times. More soluble organic compounds were produced at high temperature (65 degrees C) and pH (> 5.5) with little change in volatile solids reduction. In the second stage, harvested from a nutrient-rich culture, A. eutrophus produced PHAs from the soluble organic compounds in the supernatant of digested sludge under aerobic and nitrogen-limited conditions. The amount of PHAs accumulated in A. eutrophus accounted for 34\% of cell mass, comparable to the amount of PHAs produced from pure volatile fatty acids (33\% of cell mass). About 78\% of the total organic carbon in the supernatant was consumed by A. eutrophus. The conversions of four major acids in the supernatant by A. eutrophus were found to be 87.6\% (acetic acid), 62.6\% (propionic acid), 56.8\% (butyric acids) and 32.0\% (valeric acids), respectively. The sludge PHA is a co-polymer containing mainly C-4 monomers (74 wt \%) and has a melting point of 167 degrees C which is 9 degrees C lower than that of poly-3-hydroxybutyrate (PHB). The sludge thermoplastic and PHB had a similar biodegradability in soil, 22-27\% in 5 weeks. In sludge suspensions, 70\% of sludge plastic was decomposed and utilized by anaerobic and aerobic ba

Biodegradable thermoplastics, polyhydroxyalkanoares (PHAs), were produced from municipal sludge in a two-stage bioprocess; anaerobic digestion of sludge by thermophilic bacteria in the first stage and production of PHAs from soluble organic compounds in the supernatant of digested sludge by Alcaligenes eutrophus in the second stage. Local municipal sludge of 0.3-5 wt \% dry solids containing 50-70\% volatile solids was digested under thermophilic (50-65 degrees C) and anaerobic conditions producing a mixture of fatty acids and other minor fermentation products. The residual sludge contains about 50\% of the original volatile solids. Volatile solids reduction and formation of soluble organic compounds from sludge were investigated under different temperature, pH, hydraulic (solid) retention times. More soluble organic compounds were produced at high temperature (65 degrees C) and pH (> 5.5) with little change in volatile solids reduction. In the second stage, harvested from a nutrient-rich culture, A. eutrophus produced PHAs from the soluble organic compounds in the supernatant of digested sludge under aerobic and nitrogen-limited conditions. The amount of PHAs accumulated in A. eutrophus accounted for 34\% of cell mass, comparable to the amount of PHAs produced from pure volatile fatty acids (33\% of cell mass). About 78\% of the total organic carbon in the supernatant was consumed by A. eutrophus. The conversions of four major acids in the supernatant by A. eutrophus were found to be 87.6\% (acetic acid), 62.6\% (propionic acid), 56.8\% (butyric acids) and 32.0\% (valeric acids), respectively. The sludge PHA is a co-polymer containing mainly C-4 monomers (74 wt \%) and has a melting point of 167 degrees C which is 9 degrees C lower than that of poly-3-hydroxybutyrate (PHB). The sludge thermoplastic and PHB had a similar biodegradability in soil, 22-27\% in 5 weeks. In sludge suspensions, 70\% of sludge plastic was decomposed and utilized by anaerobic and aerobic ba

Biodegradable thermoplastics, polyhydroxyalkanoares (PHAs), were produced from municipal sludge in a two-stage bioprocess; anaerobic digestion of sludge by thermophilic bacteria in the first stage and production of PHAs from soluble organic compounds in the supernatant of digested sludge by Alcaligenes eutrophus in the second stage. Local municipal sludge of 0.3-5 wt \% dry solids containing 50-70\% volatile solids was digested under thermophilic (50-65 degrees C) and anaerobic conditions producing a mixture of fatty acids and other minor fermentation products. The residual sludge contains about 50\% of the original volatile solids. Volatile solids reduction and formation of soluble organic compounds from sludge were investigated under different temperature, pH, hydraulic (solid) retention times. More soluble organic compounds were produced at high temperature (65 degrees C) and pH (> 5.5) with little change in volatile solids reduction. In the second stage, harvested from a nutrient-rich culture, A. eutrophus produced PHAs from the soluble organic compounds in the supernatant of digested sludge under aerobic and nitrogen-limited conditions. The amount of PHAs accumulated in A. eutrophus accounted for 34\% of cell mass, comparable to the amount of PHAs produced from pure volatile fatty acids (33\% of cell mass). About 78\% of the total organic carbon in the supernatant was consumed by A. eutrophus. The conversions of four major acids in the supernatant by A. eutrophus were found to be 87.6\% (acetic acid), 62.6\% (propionic acid), 56.8\% (butyric acids) and 32.0\% (valeric acids), respectively. The sludge PHA is a co-polymer containing mainly C-4 monomers (74 wt \%) and has a melting point of 167 degrees C which is 9 degrees C lower than that of poly-3-hydroxybutyrate (PHB). The sludge thermoplastic and PHB had a similar biodegradability in soil, 22-27\% in 5 weeks. In sludge suspensions, 70\% of sludge plastic was decomposed and utilized by anaerobic and aerobic ba

Mikrovlnná pyrolýza představuje možné řešení problému likvidace vodárenských kalů. Jedním z výsledných produktů pyrolýzy je biouhel, amorfní porézní uhlíkatý materiál, který stále více nalézá uplatnění v zemědělství jako půdní kondicionér. Biouhel obvykle vykazuje hydrofobní charakter, nicméně jeho použití často vede ke zvýšení zádrže vody v půdách. Důvody tohoto zlepšení proto nelze vysvětlit pouze vysokou porozitou biouhlu. Tato práce se snaží přispět k pochopení interakce vody a biouhlu za různých environmentálně relevantních podmínek, tj. přímého přídavku vody do biouhlu a adsorpce vody při různých relativních vlhkostech vzduchu. Častými metodami, které se používají k pochopení vztahu mezi organickými materiály a vodou, jsou metody termické analýzy. Mezi ty patří i technika DSC, která byla v této práci využita. První experiment zahrnoval měření entalpie tání mrznoucí vody v pórech biouhlu, jehož výsledky poukazovaly na strukturu ledu odrážející povahu pórů v biouhlu. Dále se experiment zaměřil na stanovení množství tzv. nemrznoucí vody, která odráží především mikroporozitu systému. Nemrznoucí voda byla zjištěna extrapolací na nulovou měrnou entalpii tání a její množství činilo 0,13–0,15 mg na mg sušiny. Druhý experiment se zaměřil na výparnou entalpii vody z biouhlu, která poukazuje na to, jak silně je celková voda vázaná. Také nepřímo vede k pochopení, jakým způsobem a jak snadno se voda z biouhlu uvolňuje a naopak přijímá. Srovnáním výsledků pro vázanou a čistou vodu lze dedukovat, že vazba vody v biouhlu je asi o 10–20 % slabší. To vede k závěru, že výměna vody mezi biouhlem a půdou je poměrně rychlá i přes relativní hydrofobicitu biouhlu., Microwave pyrolysis represents a possible solution of municipal sludge disposal. One of the final products of pyrolysis is amorphous porous carbon material called biochar, which can be used in agriculture as a soil amendment. As a rule, biochar is hydrophobic, but its addition can lead to an increase in water holding capacity. However, reasons of this improvement cannot be explained only by its high porosity. This thesis aims to contribute to the understanding the interactions between biochar and water under various environmental-relevant conditions such as direct water addition method and water adsorption from ambient air at different relative humidity. The thermo-analytical methods are common for investigation of the relationship between water and organic materials. One of these methods, differential scanning calorimetry, was used in this thesis. The first experiment was focused on measuring of melting enthalpy of freezable water in biochar pores. The results reflect the influence of pore size and properties of ice structure. The extrapolation of concentration dependence to zero enthalpy was used to determine non-freezing water (0,13–0,15 mg·mg-1 biochar), which reflects microporosity of the biochar. The second experiment was focused on the determination of evaporation enthalpy of water from biochar, which is a measure of the strength of water binding in biochar. This value indirectly reflects the mechanisms of the intake and release of water by biochar. Comparing the results for bound and pure water showed that in biochar is water bound weaker about 10–20 %. This led to conclusion that biochar binds water relatively weakly and the water exchange between biochar and soil is fast, despite the biochar hydrophobicity.

Mikrovlnná pyrolýza představuje možné řešení problému likvidace vodárenských kalů. Jedním z výsledných produktů pyrolýzy je biouhel, amorfní porézní uhlíkatý materiál, který stále více nalézá uplatnění v zemědělství jako půdní kondicionér. Biouhel obvykle vykazuje hydrofobní charakter, nicméně jeho použití často vede ke zvýšení zádrže vody v půdách. Důvody tohoto zlepšení proto nelze vysvětlit pouze vysokou porozitou biouhlu. Tato práce se snaží přispět k pochopení interakce vody a biouhlu za různých environmentálně relevantních podmínek, tj. přímého přídavku vody do biouhlu a adsorpce vody při různých relativních vlhkostech vzduchu. Častými metodami, které se používají k pochopení vztahu mezi organickými materiály a vodou, jsou metody termické analýzy. Mezi ty patří i technika DSC, která byla v této práci využita. První experiment zahrnoval měření entalpie tání mrznoucí vody v pórech biouhlu, jehož výsledky poukazovaly na strukturu ledu odrážející povahu pórů v biouhlu. Dále se experiment zaměřil na stanovení množství tzv. nemrznoucí vody, která odráží především mikroporozitu systému. Nemrznoucí voda byla zjištěna extrapolací na nulovou měrnou entalpii tání a její množství činilo 0,13–0,15 mg na mg sušiny. Druhý experiment se zaměřil na výparnou entalpii vody z biouhlu, která poukazuje na to, jak silně je celková voda vázaná. Také nepřímo vede k pochopení, jakým způsobem a jak snadno se voda z biouhlu uvolňuje a naopak přijímá. Srovnáním výsledků pro vázanou a čistou vodu lze dedukovat, že vazba vody v biouhlu je asi o 10–20 % slabší. To vede k závěru, že výměna vody mezi biouhlem a půdou je poměrně rychlá i přes relativní hydrofobicitu biouhlu., Microwave pyrolysis represents a possible solution of municipal sludge disposal. One of the final products of pyrolysis is amorphous porous carbon material called biochar, which can be used in agriculture as a soil amendment. As a rule, biochar is hydrophobic, but its addition can lead to an increase in water holding capacity. However, reasons of this improvement cannot be explained only by its high porosity. This thesis aims to contribute to the understanding the interactions between biochar and water under various environmental-relevant conditions such as direct water addition method and water adsorption from ambient air at different relative humidity. The thermo-analytical methods are common for investigation of the relationship between water and organic materials. One of these methods, differential scanning calorimetry, was used in this thesis. The first experiment was focused on measuring of melting enthalpy of freezable water in biochar pores. The results reflect the influence of pore size and properties of ice structure. The extrapolation of concentration dependence to zero enthalpy was used to determine non-freezing water (0,13–0,15 mg·mg-1 biochar), which reflects microporosity of the biochar. The second experiment was focused on the determination of evaporation enthalpy of water from biochar, which is a measure of the strength of water binding in biochar. This value indirectly reflects the mechanisms of the intake and release of water by biochar. Comparing the results for bound and pure water showed that in biochar is water bound weaker about 10–20 %. This led to conclusion that biochar binds water relatively weakly and the water exchange between biochar and soil is fast, despite the biochar hydrophobicity.

Mikrovlnná pyrolýza představuje možné řešení problému likvidace vodárenských kalů. Jedním z výsledných produktů pyrolýzy je biouhel, amorfní porézní uhlíkatý materiál, který stále více nalézá uplatnění v zemědělství jako půdní kondicionér. Biouhel obvykle vykazuje hydrofobní charakter, nicméně jeho použití často vede ke zvýšení zádrže vody v půdách. Důvody tohoto zlepšení proto nelze vysvětlit pouze vysokou porozitou biouhlu. Tato práce se snaží přispět k pochopení interakce vody a biouhlu za různých environmentálně relevantních podmínek, tj. přímého přídavku vody do biouhlu a adsorpce vody při různých relativních vlhkostech vzduchu. Častými metodami, které se používají k pochopení vztahu mezi organickými materiály a vodou, jsou metody termické analýzy. Mezi ty patří i technika DSC, která byla v této práci využita. První experiment zahrnoval měření entalpie tání mrznoucí vody v pórech biouhlu, jehož výsledky poukazovaly na strukturu ledu odrážející povahu pórů v biouhlu. Dále se experiment zaměřil na stanovení množství tzv. nemrznoucí vody, která odráží především mikroporozitu systému. Nemrznoucí voda byla zjištěna extrapolací na nulovou měrnou entalpii tání a její množství činilo 0,13–0,15 mg na mg sušiny. Druhý experiment se zaměřil na výparnou entalpii vody z biouhlu, která poukazuje na to, jak silně je celková voda vázaná. Také nepřímo vede k pochopení, jakým způsobem a jak snadno se voda z biouhlu uvolňuje a naopak přijímá. Srovnáním výsledků pro vázanou a čistou vodu lze dedukovat, že vazba vody v biouhlu je asi o 10–20 % slabší. To vede k závěru, že výměna vody mezi biouhlem a půdou je poměrně rychlá i přes relativní hydrofobicitu biouhlu., Microwave pyrolysis represents a possible solution of municipal sludge disposal. One of the final products of pyrolysis is amorphous porous carbon material called biochar, which can be used in agriculture as a soil amendment. As a rule, biochar is hydrophobic, but its addition can lead to an increase in water holding capacity. However, reasons of this improvement cannot be explained only by its high porosity. This thesis aims to contribute to the understanding the interactions between biochar and water under various environmental-relevant conditions such as direct water addition method and water adsorption from ambient air at different relative humidity. The thermo-analytical methods are common for investigation of the relationship between water and organic materials. One of these methods, differential scanning calorimetry, was used in this thesis. The first experiment was focused on measuring of melting enthalpy of freezable water in biochar pores. The results reflect the influence of pore size and properties of ice structure. The extrapolation of concentration dependence to zero enthalpy was used to determine non-freezing water (0,13–0,15 mg·mg-1 biochar), which reflects microporosity of the biochar. The second experiment was focused on the determination of evaporation enthalpy of water from biochar, which is a measure of the strength of water binding in biochar. This value indirectly reflects the mechanisms of the intake and release of water by biochar. Comparing the results for bound and pure water showed that in biochar is water bound weaker about 10–20 %. This led to conclusion that biochar binds water relatively weakly and the water exchange between biochar and soil is fast, despite the biochar hydrophobicity.

Mikrovlnná pyrolýza představuje možné řešení problému likvidace vodárenských kalů. Jedním z výsledných produktů pyrolýzy je biouhel, amorfní porézní uhlíkatý materiál, který stále více nalézá uplatnění v zemědělství jako půdní kondicionér. Biouhel obvykle vykazuje hydrofobní charakter, nicméně jeho použití často vede ke zvýšení zádrže vody v půdách. Důvody tohoto zlepšení proto nelze vysvětlit pouze vysokou porozitou biouhlu. Tato práce se snaží přispět k pochopení interakce vody a biouhlu za různých environmentálně relevantních podmínek, tj. přímého přídavku vody do biouhlu a adsorpce vody při různých relativních vlhkostech vzduchu. Častými metodami, které se používají k pochopení vztahu mezi organickými materiály a vodou, jsou metody termické analýzy. Mezi ty patří i technika DSC, která byla v této práci využita. První experiment zahrnoval měření entalpie tání mrznoucí vody v pórech biouhlu, jehož výsledky poukazovaly na strukturu ledu odrážející povahu pórů v biouhlu. Dále se experiment zaměřil na stanovení množství tzv. nemrznoucí vody, která odráží především mikroporozitu systému. Nemrznoucí voda byla zjištěna extrapolací na nulovou měrnou entalpii tání a její množství činilo 0,13–0,15 mg na mg sušiny. Druhý experiment se zaměřil na výparnou entalpii vody z biouhlu, která poukazuje na to, jak silně je celková voda vázaná. Také nepřímo vede k pochopení, jakým způsobem a jak snadno se voda z biouhlu uvolňuje a naopak přijímá. Srovnáním výsledků pro vázanou a čistou vodu lze dedukovat, že vazba vody v biouhlu je asi o 10–20 % slabší. To vede k závěru, že výměna vody mezi biouhlem a půdou je poměrně rychlá i přes relativní hydrofobicitu biouhlu., Microwave pyrolysis represents a possible solution of municipal sludge disposal. One of the final products of pyrolysis is amorphous porous carbon material called biochar, which can be used in agriculture as a soil amendment. As a rule, biochar is hydrophobic, but its addition can lead to an increase in water holding capacity. However, reasons of this improvement cannot be explained only by its high porosity. This thesis aims to contribute to the understanding the interactions between biochar and water under various environmental-relevant conditions such as direct water addition method and water adsorption from ambient air at different relative humidity. The thermo-analytical methods are common for investigation of the relationship between water and organic materials. One of these methods, differential scanning calorimetry, was used in this thesis. The first experiment was focused on measuring of melting enthalpy of freezable water in biochar pores. The results reflect the influence of pore size and properties of ice structure. The extrapolation of concentration dependence to zero enthalpy was used to determine non-freezing water (0,13–0,15 mg·mg-1 biochar), which reflects microporosity of the biochar. The second experiment was focused on the determination of evaporation enthalpy of water from biochar, which is a measure of the strength of water binding in biochar. This value indirectly reflects the mechanisms of the intake and release of water by biochar. Comparing the results for bound and pure water showed that in biochar is water bound weaker about 10–20 %. This led to conclusion that biochar binds water relatively weakly and the water exchange between biochar and soil is fast, despite the biochar hydrophobicity.