Volume 19 (2011): Issue 31 (January 2011)

The submitted article discusses rotational moulding technology and filled plastics. For testing, linear low density polyethylene filled with talc was used. The materials tested varied way of mixing the filler into the polymer. For the prepared samples were evaluated by tensile, elongation, melt flow index, density, Shore hardness and Vicat softening temperature. Experiments showed that, in principle, it is possible to produce rotational moulding technology filled thermoplastics.

The paper deals with the process of building a laboratory-scale biogas plant and verifying its functionality. The laboratory-scale prototype was constructed in the Department of Safety and Environmental Engineering at the Faculty of Materials Science and Technology in Trnava, of the Slovak University of Technology. The Department has already built a solar laboratory to promote and utilise solar energy, and designed SETUR hydro engine. The laboratory is the next step in the Department's activities in the field of renewable energy sources and biomass. The Department is also involved in the European Union project, where the goal is to upgrade all existed renewable energy sources used in the Department.

The paper deals with utilization possibilities of solar energy (photovoltaic systems) and with transformation of this energy to chemical energy as well as its utilization in the surface treatment of metals by electrochemical processes. Surface treatments significantly contribute to the resulting quality of technical equipment. Surface treatments affect lifetime, serviceability, usability, availability and maintenance of equipment. This technology can be widely applied in machine industry in the future due to cheap electrical energy generation. Next advantage of this electrical energy generation is the decrease of negative environmental impact. The whole system is now usable for bright copper plating, but owing to the low capacity, we can use it only for the objects of small areas, around 1.10 dm², 4.39 dm² in ideal conditions.

The aim of this contribution is to measure the effect of the pretreatment of lignocellulosic phytomass utilization for bioethanol production. The first step of bioethanol production from lignocellulosic phytomass is pretreatment of raw material. The next step is hydrolysis, and then the fermentation of sugars follows. The physical (grinding, breaking) and chemical (ozonization) processes were used as pretreatment. Ozone was applied to the aqueous suspension of lignocellulosic phytomass before and during the hydrolysis. Ozone pretreatment did not perform as effectively as expected. The results of study, which are focused on evaluation of reducing sugars are included in this contribution.

The main aim of this study was to evaluate toxicity of metalworking fluids to bacterial consortium of activated sludge according to OECD 209 (STN EN ISO 8192) and a potential of the same sludge to degrade a part of the fluids according to OECD 302B.

Toxic impact can affect different responses, particularly the inhibition of respiration measured from the oxygen consumption in a closed bottle. The degradation rate was calculated from COD according to the authors such as van der Gast and Ian Thompson (1, 2) who tested the degradability of some MWFs in bioreactors by measuring the COD. The lowest toxic MWF's were Cimstar 597 and Emulzin H (the highest tested concentration was below EC₅₀), then Zubora TXS (EC₅₀ - 11 349 mg l^-1), Aquamet LAK-E (EC₅₀ - 5 228 mg l^-1), Adrana D 407 (EC₅₀ - 4 351 mg l^-1) followed, and finally, Hocut 3380 (EC₅₀ - 2 339 mg l^-1) was assessed as the most toxic.

Important in this test (OECD 302B) is that the starting concentration of the tested substance must not decrease below 20% after 3 hours of cultivating. After that, it is impossible to distinguish biological degradation of organic matter from abiotic elimination from the suspension through adsorption. Tested were 8 MWFs of similar concentration and different addition of activated sludge - 0.25 g l^-1, 0.50 g l^-1 and 1.00 g l^-1. The test showed that, after the first 3 hours of cultivating, adsorption grew with the increasing amount of inoculums, except of Akvol B (the decrease of the starting concentration after the first 3 hours of cultivating was the lowest of all and below 20%). It can be stated that, according to the test basic conditions, all the tested MWFs have a potential to ultimate degradation.

The article presents the results of leaching experiments regarding the comparison of chemical and biological-chemical leaching of ores from the Sb-(Au-) base metal deposit Pezinok (Malé Karpaty., the Western Carpathians) under the same conditions in solution. Discussed are the differences between chemical and biological-chemical leaching activity. The extent and the kinetics of the biological-chemical leaching of the technogenous sediments from the setting-pits are significantly higher than those without bacteria.

Top managers are aware of the necessity of open and honest informing about their environmental activities, which is preconditioned by the development, maintenance and subsequent improvement of the system of environmental informing in the enterprise. Environmental reporting is a tool for providing information about organisation's activities and their impact on environment.

The paper shows that environment is one of the basic public assets of a human system, and it must be therefore specially protected. According to our present knowledge, the sustainability is necessary for all human systems and it is necessary to invoke the sustainable development principles in all human system assets. Sustainable development is understood as a development that does not erode ecological, social or politic systems on which it depends, but it explicitly approves ecological limitation under the economic activity frame and it has full comprehension for support of human needs. The paper summarises the conditions for sustainable development, tools, methods and techniques to solve the environmental problems and the tasks of executive governance in the environmental segment.