ON INFLUENCE OF MAGNETIC STRUCTURE ON THE ELECTRIC CHARGE TRANSPORT IN SAMARIUM AND THULIUM THIN FILMS

The temperature dependence of the electrical resistivity of samarium and thulium thin films has been studied in the temperature range from 4.2 K to 300 K. The influence of magnetic structure on the resistivity is clearly seen on the obtained resistivity vs. tem- perature dependences of Sm films prepared by evaporation in high vacuum as well as that of Tm films prepared in UHV. The obtained values of Néel temperatures are lower than those of bulk samples and decrease with decreasing film thickness. Residual resistance ratio exhibits similar behaviour as Néel temperature

Removal of BTX Contaminants with O3 and O3/UV Processes

The legal basis for the monitoring of priority and priority hazardous substances in water, sediment, and biota follows from Directive 2008/105/EC which defines the good chemical status to be achieved by all Member States together with the Water Framework Directive 2000/60/EC. The BTX compounds are considered to be the most toxic components of gasoline. Thus, organic petroleum components can induce a serious problem to public health and the aquatic environment. The effect of ozone and ozone/UV on degradation of the BTX in a model water was studied. The results indicate that the highest BTX removal rates were observed during the first 5 min of the process for all investigated pollutants. The treatment efficiencies above 90% were observed in all investigated pollutants after 40 min of ozonation. The results show a significant proportion of stripping in the removal of BTX components. Higher overall efficiency was observed by O3/UV process after abstracting share of stripping process. Application of investigated processes appears to be a promising procedure for removal of petrol aromatic hydrocarbons from aquatic environment. However, for practical application, an improvement of process removal efficiency and investigation of impact of ozonation intermediates and products on aquatic microorganisms are required

Influence of Phosphorus Precipitation on Wastewater Treatment Processes

Phosphorus stimulates aquatic plant growth and contributes to eutrophication process in rivers, lakes and the ocean. A large part of phosphorus is discharged into the receiving waters by wastewater. One of the solutions of this problem is represented by chemical precipitation. Simultaneous precipitation of phosphorus from wastewater with metal salts is commonly applied. Metal salts are dosed directly into aeration tank, and produced precipitates are wasted as a part of the secondary sludge. Thus, not only aerobic and anoxic processes of wastewater treatment plant are carried out in the presence of precipitant metals and precipitates but also the precipitates are, in many cases, accumulated in anaerobic sludge digesters. Operational research of phosphorus precipitation in lab‐scale encompasses the impact of Fe2+, Fe3+ and Al3+ salts on biological nitrification and denitrification processes, sedimentation and thickening characteristics of sludge as well as anaerobic sludge stabilisation processes. The measurements of specific oxygen uptake rate, nitrification and denitrification tests and monitoring of effluent values of quality standards were applied to evaluate the processes performance. Other objective of our research is to contribute to methodology for examination of thickening and dewatering characteristics of sludge with tested precipitation agents. Mathematically processed experimental results are used to compare sedimentation, precipitation and dewatering characteristics of activated sludge cultivated in the presence of selected precipitation agents. Better description of the experimental results was obtained with three parameters model of particles mass flow density curve. Comparison of minimum sedimentation tank size necessary for gravitational separation of individual sludge was used to examine sedimentation characteristics of activated sludge. Thickening characteristics of sludge were evaluated based upon thickening area needed to maintain the required sludge concentration in activated sludge model, which corresponds to maximum surface load in undissolved substances. Chemical precipitation of phosphorus produces metal precipitates. These are transported with the waste sludge to the digestion tanks. Impact of the precipitates on the anaerobic sludge stabilisation process as well as on the sludge water quality was tested in the work. The main aim of the research and proposed chapter submission is a pursuit of decision making regarding selection of type of precipitating agent and strategy of chemical phosphorus precipitation

Influence of magnetic field on electric charge trasport in Holmium thin film at low temperature

High precision electrical resistance measurements were performed in the low temperature range from 4.2 K up to room temperature on a holmium bulk sample, and on holmium thin films in magnetic field. The X-ray diffraction of Ho films confirmed their preferential crystal orientation and revealed diffraction peaks originating from the h.c.p. structure of Ho and those from inessential holmium dihydrid content. The TN value of these films decreased with decreasing film thickness. Magnetic field applied parallel to the thin film plane caused an increasing suppression of the TN value up to 5 K with increasing flux density value up to 5 T

Design, Scale-Up, and Construction of Drinking Water Recarbonization Fluidized Bed Reactor System

The lack of calcium and magnesium in drinking water affects people’s health, especially cardiovascular and oncologic diseases, and causes corrosion problems. The aim of this paper is to present the methodology of the design, scale-up, and construction of a fluidized bed reactor (FBR) system for drinking water recarbonization with biogenic elements in real conditions. Half-calcined dolomite (HCD) in combination with CO2 was identified as a suitable source of Mg2+ and Ca2+. The experimental results confirmed that an FBR reactor with a water tank is an efficient system for Mg and Ca2+ ion concentrate production. The main process parameters and dimensions of the equipment were determined based on the experimental data and the data obtained showed that the system can be used in real conditions to produce Mg2+ and Ca2+ ions concentrate, which is mixed with soft water in required proportions. The FBR with an internal diameter of 0.16 m and a total height of 3.7 m was designed. The proposed methodology of the recarbonization process design was used in a further system scale-up for a ten times larger capacity. Long-term experiments indicate that the HCD recarbonization process is robust and can return to the steady state even after significant changes in the process parameters for providing the desired concentration of Mg2+ and Ca2+ ions in drinking water

Removal of micropollutants by ozone-based processes

Micropollutants and emerging substances pose a serious problem to environmental sustainability and remediation, due to their widespread use and applications in everyday life. This group of chemicals is diverse but with common toxic and harmful properties. Their concentration in the environment is often very lowhowever, due to their recalcitrant nature, they are persistent in air, water, and soil. From an engineering point of view, the challenge is not straightforward. It is difficult to remove these contaminants from complex mixtures of substances by conventional methods used in wastewater and drinking water treatment. Ozonation and ozone-based AOPs are accepted processes of degradation of resistant substances or at least enhancement of their biodegradability. The aim of this review paper is to present research trends aimed at solving problems in the research and application of ozone-based processes in the removal of micropollutants from wastewater, thus preventing leakage of harmful substances into surface water, soil, and groundwater and facilitating the reuse of wastewater. Priority substances, micropollutants and emerging pollutants, as well as processes and technologies for their transformation and elimination, are briefly specified. Results obtained by the authors in solving research projects that were aimed at eliminating selected micropollutants by ozonation and ozone-based AOPs are also presented. This review focuses on selected alkylphenols, petroleum substances, and organochlorine pesticides