Gigel Paraschiv

A Review Regarding the Biogas Production Through Anaerobic Digestion of Organic Waste

Globally, the pollution prevention goals transposed in the Kyoto Protocol, require sustainable solutions regarding the management of organic waste from both agricultural, and livestock farms. Biogas production by anaerobic digestion of organic wastes and residues provides a range of socio-economic benefits, but also environmental, thus contributing to monitoring the complex relationship between human health and the environment. The European Union policies regarding renewable energy systems (Europe 2020 Strategy – A strategy for smart, sustainable and inclusive growth and Green Paper „Towards a European strategy for the security of energy supply“), highlights that the production of renewable energy, reducing greenhouse gas emissions and a sustainable waste management, are essential for sustainable development in the future. In this context, this paper will review aspects of biogas production by anaerobic digestion of organic waste, stages of anaerobic digestion process and concepts of biogas plants used in European countries.

FEM Modeling of Stress Distribution and Displacement in Clayey Soils during Artificial Compaction

Knowledge of soil behavior under compressive loads is important in order to prevent or minimize the impact of soil compaction on the environment and agricultural production. The aim of this study was to simulate the behavior of a clayey soil under wheel loads applied by an agricultural trailer. For known characteristics of the soil, wheel loads of 4.5 kN and 21 kN and tire inflation pressures of 180, 240 and 300 kPa, were obtained the models of stress distribution and soil displacement. For 300 kPa tire inflation pressure and 21 kN wheel load, were obtained: maximum stress of 175 kPa concentrated in the topsoil at about 140 mm depth, with smaller significant values distributed to 380 mm, and maximum soil displacement of 28.1 mm.

A COMBINED METHOD FOR THE ANALYSIS AND ASSESSMENT OF RISKS AND INDUSTRIAL SAFETY

Risk can be defined as the probability that an existing hazard could turn into an accident. It can be evaluated through the potential losses in the manufacturing process or the harmful level of accidents with an impact on human health, caused by unpredictable technical events. Romanian authorities have not found yet a nationwide method for evaluating the risks in the establishments that fall under the scope of the SEVESO Directive. Starting from the potential risk that an accident might occur in the establishments where dangerous substances are used in the processing activities, with serious consequences for both the establishments themselves and their immediate surroundings, it is necessary that a combined, complex method be found in order to consider the appropriate protective/intervention measures/actions for limiting and eliminating the consequences of potential major accidents. After the implementation of the EU legislation, in Bacau County, there were identified five operators in 2015 that fall under the scope of SEVESO II Directive as presenting major-accident risks, and six exposed to minor risks the establishments being located nearby highly vulnerable populated areas. For these establishments, risk analyses must be done in order to prevent technological accidents and manage emergencies (accidents have already occurred at some of the establishments). The results of these analyses could be used to inform, instruct, and prepare the population to act adequately in case of accidents. These aspects led us towards the decision to study the already existing risk and industrial safety assessment methods in order to develop a new method that will meet the requirements of the Romanian establishments that use dangerous substances. This paper proposes a new risk assessment method to establish the risks associated to the use of dangerous substances in manufacturing processes. It is based on a combination of the strengths of the already existing risk assessment methods at the international level. It is aimed at determining, both quantitatively and qualitatively, the risk or safety level for the installations/technologies used in the manufacturing process, which can lead to major accidents with serious consequences for man and environment. The most common risk assessment methods currently used are: Mosar, Aramis, Checklist, Octave, and Mehari methods. By combining the strong points of these methods, this paper proposes a new risk assessment method called CARMIS/DS: Combined Analysis Risk Method and Industries Security/Dangerous Soubstances.

MATHEMATICAL MODELLING OF SOUND PRESSURE LEVEL ATTENUATION TRANSMITTED BY AN ACOUSTIC SCREEN IN INDUSTRIAL ENVIRONMENT

This paper presents a three-dimensional mathematical model which characterizes the variation of sound pressure level propagation and the variation of attenuation of the sound pressure level propagated in an enclosed space. The variable taken into consideration both in the experiments and in the mathematical modeling were: the positions of the acoustic screen to noise source; the height of the microphone to record the sound pressure level for a variable number of walls. The mathematical model is based on the experimental data obtained in laboratory, using an experimental setup, which comprises a variable number of walls as acoustic screen.

SYSTEM FOR DYNAMIC MONITORING AND WARNING IN CASE OF ECOLOGICAL RISK FOR SURFACE WATERS

The dynamic monitoring system continuously performs the monitoring of physicochemical quality indicators of water quality in investigated areas. In case of ecological risk due to accidental pollution situations, the system alarms in real time the decision factors for the diminution of the environmental impacts and other negative effects. The distributed networks of the system are composed of floatable structures of Buoys Monitoring (BM) type, autonomous and adaptable to the environmental conditions specific to a continental climate. They are able to work with reduced maintenance in isolated locations. The BM floatable structure incorporates the sensors and the hardware-software system of data acquisition, processing and transmission. So equipped, BM becomes operational instrument in the infrastructure of the networks of surface waters quality monitoring. The BM model developed allows the continuous in situ evaluation of the health status of the monitored surface water with the scope of warning in case of ecological risk.

Method for preventing air pollution: Methane oxidation by two types of catalysts

Abstract Methane oxidation using different catalysts is an useful process for preventing air pollution. This study presents the methane oxidation by two types of catalysts: Pd-Sn/Al2O3 and spinel mixed oxide, CuFe2O4. The Pd-Sn/Al2O3 was successfully prepared by sol-gel method and CuFe2O4 by co-precipitation method. The catalysts obtained have been characterized structurally, morphologically and texturally by X-ray diffraction (XRD), scanning electron microscopy (SEM) and specific surface area (BET). The catalytic activity tests regarding methane oxidation were also performed.