Phenol is a major pollutant in the waste waters coming from coal processing. Hydrodynamic cavitation presents a novel technology for phenol removal from waste waters. Hydrodynamic cavitation device with a cavitator of Ventury type for waste water purification was constructed. The hydraulic characteristic of the device were determined: the dependences of flow and cavitation number on inlet pressure. The effects of cavitation number, phenol concentration, pH, temperature, time, and quantity of added H202 on the degree of phenol reduction in the waste water was investigated. The optimal technological parameters of the investigated cavitation purification process of waste waters from phenol were determined.

Advancements in computer capabilities enable predicting process outcomes that earlier could only be assessed after post-process analyses. In aerospace and automotive industries it is important to predict parts properties before their formation from liquid alloys. In this work, the logistic function was used to predict the evaporation rates of the most detrimental impurities, if the temperature of the liquid aluminum alloy was known. Then, parameters of the logistic function were used to determine the transition points where the reaction order was changing. Samples were heated to 610 °C, 660 °C, 710 °C, and 760 °C for one hour, after which the chemical analyses were performed and evaporation rates were calculated for Cd, Hg, Pb and Zn elements. The pressure inside the encapsulated area was maintained at 0.97 kPa. Whereas parameters that define the evaporation rate increase with the temperature increase, the maximum evaporation rates were deduced from the experimental data and fitted into the logistic function. The elemental evaporation in liquid-aluminum alloys is the best defined by the logistic function, since transitions from the first to zero-order-governed evaporation reactions have nonsymmetrical evaporation rate slopes between the lowest and the highest evaporation rate point.

The more economically viable and environmentally sustainable approach for treating the by-products of coal combustion from thermal power plants entails their collective disposal as opposed to individual disposal methods. This aligns with pertinent EU directives and domestic regulations, ensuring compliance with established standards while optimizing resource utilization and minimizing environmental impact. This study evaluated the resistance to wind erosion of the binding properties of a mixture (fly ash (FA), bottom ash (BA), and additives) using an indoor wind tunnel under simulated ambient conditions. Investigations of the mutual impact of ash, bottom ash, and additives (CaO and Ca(OH)₂) with a certain percentage of water were carried out with eighteen samples. The samples consisted of the water at six addition rates 5, 8, 10, 15, 20, and 25% (w/w), and additive at three addition rates (1, 2, and 3% (w/w). Based on the obtained results, the optimal ratios of additives (3% (w/w)) and water (15% (w/w)) were determined. Prior to the wind tunnel experiments, and according to the different addition rates of additives and water, eight samples were prepared with different addition rates of ash. The mass concentrations of suspended particles (PM₁₀) and total suspended particles (TSPs) in these samples were measured at three distinct wind velocities: 1 m/s, 3 m/s, and 5 m/s, respectively. The results indicate that the samples containing the optimal content of additives and water demonstrate a maximum increase in PM₁₀ emission zero values of no more than 1.9 times. This finding can be considered satisfactory from the standpoint of environmental protection.

Flue Gas Desulphurisation (FGD) technologies play a pivotal role in mitigating environmental pollution stemming from coal-fired power plants, with wet limestone FGD standing out for its high desulphurisation performance and cost-effectiveness. The urgent need to reduce SO2 emissions underscores the significance of wet limestone FGD systems, which have demonstrated remarkable efficacy in mitigating these emissions while maintaining relatively low operating costs. Flue gas desulfurization gypsum (FGDG) is a by-product of the flue gas desulfurization process in coal-fired power plants. Its chemical and physical properties make it suitable for various applications. However, despite its increasing production, its beneficial usage has declined over the past decade due to the presence of hazardous elements like arsenic, mercury, cadmium, lead, and selenium. Recent advancements in flue gas desulfurization technology have led to a reduction in these elements in "modern" FGDG, making it more attractive for reuse in other products. This paper presents results from a new FGD plant meeting guaranteed values and explores novel and traditional FGDG applications with minimal environmental impact. The quality of the by-product gypsum, wastewater, and disposal gypsum was meticulously analyzed at the flue gas desulfurization plant situated at TPP 'Nikola Tesla A', on units DC2 and DC1. Specifically, the paper discusses the recycling of FGD gypsum for the removal of Pb(II), Cd(II) and other hazardous trace elements from wastewater. By highlighting these applications and addressing research gaps, the aim is to promote greater reuse of FGDG and mitigate environmental concerns.

Optimization of field geological, geotechnical exploration and laboratory tests in order to design solar power plants in areas larger than 10 ha and in anthropogenic environments (mine waste dumps or flotation waste dumps) is imposed as a primary goal for researchers, explorers and designers. How to cover with the required number of exploration and laboratory works, the exploration area for the construction of a solar power plant, which is in most cases heterogeneous, in terms of lithological composition, physical and mechanical properties and chemical characteristics? In these cases, geotechnical studies are very complex, with a multidisciplinary approach to the analysis of the subject site for construction, in compliance with the current legislation, regulations, norms and standards. In order to optimize the designed methods in exploration areas intended for the construction of photovoltaic plants, and bearing in mind the fact that thermal conductivity depends on the type of soil, humidity and temperature, the obtained results of geophysical tests were correlated with the results of chemical analyses performed on soil samples from exploration boreholes (pH and SO4 2 -) performed at mining waste dumps. The paper presents correlative analyses of the results of geophysical tests and chemical analyses from 5 locations of mine waste dumps in the vicinity of Bor and Majdanpek, which are intended for construction of solar power plants.