Environmental contamination of rubber from waste tyres poses a risk to the environment. Rubber particles from tyres enter the environment due to the abrasiveness of the road surface. The aim of the scientific work was to observe the biological degradability of waste tyres in aquatic environment and its ecotoxicity. Biodegradability was observed under aerobic and anaerobic conditions that simulate both aerobic and anaerobic conditions in the aquatic natural environment. Aerobic conditions in the aquatic environment take place in flowing fresh water, sea water, lakes. Leachate was prepared to simulate the behaviour of tyres in an aqueous environment. Aerobic degradability was evaluated through complete biodegradability using a 301 F manometric respirometry test. Anaerobic biodegradability was evaluated by measuring biogas production using OECD 311 Anaerobic Biodegradability of Organic Compounds in Digested Sludge. For a better simulation of the natural environment, the pH of the leachates from the tyres was adjusted to a neutral range. It should be noted that standard degradability tests were extended by 7 days due to low biodegradability. Adjusting the pH during the biodegradability test is also a modification of the original test. This modification was used to better simulate biodegradability when the pH of tyres in the natural environment is reduced by acid rain. An essential part of monitoring the behaviour of waste tyres was the assessment of ecotoxicity using standard tests. The contribution of the scientific article lies in the evaluation of the course of decomposition in aerobic and anaerobic conditions with and without pH adjustment and in the use of modified biodegradability tests. The benefit of the scientific work is in the determination of the biodegradability of waste tyres with and without pH treatment, which simulate a comparison of the degradability of tyres in an acid rain environment. Another benefit of the scientific work is the depiction of biodegradation using 3D modelling with calculations of 100% degradability at different input concentrations of waste tyres. Modelling was used for the time for the absolute decomposition of tyres without pH adjustment (outside the acid rain environment) and with pH adjustment (in the acid rain environment). By monitoring, it is possible to determine whether acid rain as an anthropogenic activity influences the degradability of waste tyres in the natural environment. Biodegradability tests confirmed the low biological degradability of waste tyres. The highest average rate of biological degradability—15% was recorded at the input concentration of waste tyres of 350 mg/L. The aerobic degradability test confirmed the improvement of tyre decomposition when adjusting the pH to the level of 6.5–7.5. On the contrary, the anaerobic degradability test confirmed the improvement of the decomposition in the alkaline region compared to the neutral pH values of the mixture. By mathematical–statistical evaluation of aerobic decomposition with preservation of degradability trends at three input concentrations, the time of absolute decomposition of waste tyre particles at a concentration of 370 mg/L was found to be approximately 336 days. By adjusting the pH to the neutral range during aerobic decomposition, the total decomposition time was reduced to 126 days. The ecotoxicity tests performed confirmed the toxic effect of tyre leachate on selected tested organisms. In the future, the authors propose to focus on a more detailed assessment of the ecotoxicity of the waste conditions and to modify the biodegradability tests by changing the conditions (wider range of input pH value, longer biodegradability time, temperature) for a better simulation of different types of environments. Adjusting the pH to a neutral environment increased aerobic degradability but had no significant effect on anaerobic degradability. Therefore, it is important to focus future research on the adjustment of various conditions to support the degradability of tyres, of which pH has clearly been confirmed as an important factor.

This review is focused on various possibilities of application of foundry sands. The evaluation was performed by summarizing available resources. The application of waste sand as an admixture in concrete brings with it economic advantages compared to the use of exclusively natural sand in the production of concrete. On the other hand, due to the mechanical properties, only a 10–20 % substitution of natural material with waste sand appears to be optimal. Road construction works provide an opportunity to reuse large amounts of surplus material, including foundry sand waste. High demands on the properties of the embankment (low internal deformation, sufficient shear strength, homogeneity, erosion resistance) are required for this application. Waste sands are a suitable substitute for clay cladding material. It is necessary to consider various criteria for the application of waste sand – economic, technical or environmental benefits. In the future, research should focus on evaluating the use of waste foundry sands in grasslands. There is currently insufficient knowledge to evaluate this application.

Mine water is one of the factors threatening the environment. The aim of the review article is to discuss and critically evaluate individual strategies for the remediation of neutral mine water. A critical evaluation is an essential tool to determine an appropriate remediation strategy. A wetland system is the preferred method of metal removal. However, the disadvantage is that it takes up more space compared to other methods and has a lower metal removal efficiency compared to active metal removal methods. When creating a suitable strategy, it is also necessary to assess the conditions of the mining site, which partially or completely prevent the use of the selected remediation strategy. The benefit of this review article is the processing of suitable combinations of treatment methods for the removal of potentially hazardous elements and their subsequent recovery. Future research in the field needs to focus on the analysis of the negative aspects of the environment that may disrupt or support the implementation of the selected method of remediation.

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Organic waste from production processes is unutilised potential for the production of energy from renewable sources. The submitted paper studies the conditions of anaerobic degradation of selected waste from food industry (diary and distillery) when biogas is produced. Both types of organic waste have low pH values. Ash form municipal incineration as a material for the treatment of pH of waste was used. Except for the pH increase during anaerobic degradation, ash also serves as a source of macroelements for inoculum microorganisms. Kinetics of anaerobic biological digestion of organic material based on the change of pressure and biogas production depending on the ash addition (change of pH) of input samples was observed. Beside these tests, degradability of the waste was assessed by limiting biologically degradable ratio, BR and specific speed of degradability, q. pH values were adjusted with different amounts of ash (0.5; 1.8; 2.7 g/g of dry matter of organic material). Results of the research confirmed that the addition of optimum amount of ash has a positive effect on anaerobic degradation of organic materials.