Hydrogen is considered a powerful fuel for the future. Hydrogen production technologies vary widely. Green hydrogen is generated by electrolyzing water with electricity produced from renewable energy sources. According to the stoichiometry reaction, 9 kg of water is consumed to produce 1 kg of hydrogen. The water to be electrolysed has to meet stringent requirements and its preparation generates large quantities of wastewater, which should be managed appropriately. The objective of this research is to examine the methods by which water is prepared depending on its source and to determine the level of wastewater generated by its treatment. The results of the analyses carried out indicate that the water abstraction associated with green hydrogen production is significantly higher than the 9 kg per 1 kg of hydrogen value reported in numerous studies.

Introduction: Analysis of aboveground vegetation and soil seed bank is an important source of data on the state and dynamics of vegetation. It is especially important in landscapes exposed to disturbances, which have lost their functions. For our research, a post-mining area in the region of the Upper Silesian Black Coal Basin was selected, whose relief and ecosystems are strongly disturbed by underground mining and are currently also affected by ongoing climate change.Method: Data collection for our research took place in the territory of two waterlogged subsidence basins in the Karvina region, Czech Republic. We evaluated 30 phytosociological releves using techniques of Zurich – Montpellier school and 540 soil cores using cultivation and extraction method.Results: In the above-ground vegetation, 115 plant species were identified. By cultivating soil samples, we determined 60 species from 1,487 seedlings, by extraction method 66 species from 5,999 seeds. A statistically significant effect of the presence of the tree layer on the number of species obtained by the extraction method was demonstrated. There is also a statistically significant difference between the selected analysis methods in terms of the length of the captured seeds and their seed mass.Discussion: The construction of a rarefaction curve demonstrated that the use of cultivation and extraction methods leads to a greater capture of soil seed bank species. The similarity between the species composition of aboveground vegetation and the soil seed bank correspond to similarities observed in other studies from degraded habitats. Very low similarity between the species of the soil seed bank from cultivation and extraction method is probably caused by the highly variable distribution of seeds in the soil in time and space.

This article deals with the possibilities of population management of invasive and in Czech Republic no - native species Helianthus tuberosus. We have chosen study areas in Poodri PLA, it is located near the industrial city Ostrava (Moravian-Silesian region). Invasive Helianthus tuberosus forms monodominant vegetation, excludes the original and often rare plant species and reduces biodiversity. It is a risk for the further development of the landscape of Poodri PLA. There is no known effective way to dispose of invasive Helianthus tuberosus so far. We have applied the proposed management works on 15 monitoring areas and then evaluated their effectiveness. We have used chemical (herbicides) and mechanical (mowing, digging up) methods and their combinations. The most effective was the combination of 3 interventions: manual mowing - spraying – mowing by mechanization, just mowing itself rather promotes the spread of the population. We can say this is a pilot study from a long-term project dealing with the effectiveness of different ways of invasive plants management.

Overall amount and quality of seeds reaching the area is an important factor in the development of plant communities in each habitat. It can be a significant source of diversity in anthropogenically disturbed areas. This study is focused on the survey of seed rain in habitats of waterlogged subsidence basins of the Karviná region, induced by deformations of overlying rocks in the area of deep coal mining. The density, species composition and dispersal strategies of captured seeds were monitored using funnel traps with a 35 cm diameter, fixed at a height of 0.5 m. A vegetation study was conducted to compare seed rain with above-ground vegetation using the Jaccard similarity index. Over 11 000 seeds of 27 plant species were captured in total. Seed rain was dominated by Salix alba species. Seed density varied significantly within individual sampling plots (7–12380 seeds/m2) with the average richness of four species. The diversity of above-ground vegetation was also low, with an average of 15 species per plot (100 m2). Similarity between seed rain and above-ground vegetation of subsidence basins is 27.6 % and 52 % within the woody species community. It is evident that the seed rain of waterlogged subsidence basins contains species of floodplain forests and wetland vegetation. On the other hand, invasive and expansive species identified both in seed rain and above-ground vegetation can potentially endanger the development of the succession of these habitats. The analysis of seed dispersal also shows a significant proportion of species of arid and mesic habitats. Keywords: Dispersal strategy; Karviná; Seed rain; Subsidence basin.

Along with the current increase in the number of biogas plants, huge amounts of digestate, i.e. waste products, are being generated. The common practice in the Czech Republic is to plough the digestate into the land. In our field trial, we compared the fertilizing effects of standard fertilizers applied in the Czech Republic with digestate as the only fertilizer (e.g. digestate fibre and digestate liquor) in real agricultural conditions to find out whether a comparable amount of nitrogen is used in accordance with European legislation. The impact of separated digestate fibre and separated liquor on the soil fertility and quality was observed on the basis of the distribution of macro- and micronutrients in maize. The evaluation of growth increments in maize suggests that the fertilizing effects of digestate liquor or digestate fibre do not match the standard fertilizer in agriculture, but especially digestate liquor is comparable with other mineral fertilizers. Our field trial also shows that digestate liquor is a better fertilizer than digestate fibre, which may be explained by more appropriate ratios of available nutrients in digestate liquor. Digestate fibre may be recommended mainly for the aeration of clayey soil, but is not sustainable as fertilizer.

This study evaluates the feasibility of using pretreated domestic wastewater (PDW) for food production in a hydroponic system. In the face of increasing water shortage problems and rising fertilizer costs, PDW combined with a limited amount of fertilizer is evaluated for its effects on plant growth, biomass yield, and product safety. The results showed that lettuce grown with PDW and mineral fertilizers reached a fresh weight of 116, while the use of organic fertilizers increased the yield to 127 g, compared to only 54 g with raw water. Nitrate concentration (NO₃) was higher in lettuce grown with organic fertilizers (1044.33 ± 144.04 mg/kg) than with mineral fertilizers (623.33 ± 85.62 mg/kg), but the values remained well below the acceptable limit of 5000 mg/kg for safe consumption. Analysis of heavy metals confirmed that levels of arsenic, cadmium, mercury, and lead were significantly lower than the maximum permissible values set by FAO and EU regulations. In addition, no phthalates were detected in the lettuce biomass, confirming the safety of the materials used in the hydroponic system. The use of PDW in hydroponic crops significantly reduces dependence on potable water and synthetic fertilizers, contributing to sustainable resource management. This approach not only reduces production costs, but also reduces the water footprint of crops, which is crucial in the context of global water availability problems. The findings support the validity of using PDW in decentralized food production as a sustainable solution for regions facing water and fertilizer shortages. Further research will focus on optimizing nutrient management and environmental conditions to increase system efficiency and food safety.