Elena Bucur

PERFORMANCE EVALUATION OF THE METHODS USED FOR THE DETERMINATION OF SULFUR CONTENT IN FUELS AND BIOFUELS

This paper presents the results of an experimental research study having as objective the development of a routine method based on ion – chromatography technique, used for the sulfur content determination in solid and liquid fuels. The proposed procedure was applied on the determination of total sulfur in samples of coal, fuel oil and biomass with different sulfur content ranging from 0.05 % to 0.6 %. The methodology consists of the sample preparation by Eschka method based on igniting a test portion of coal sample in intimate contact with Eschka mixture at 800C , or by combustion of the fuel oil or biomass sample in a closed system containing oxygen (calorimeter bomb), followed by the selective determinations of sulfur content using ion-chromatography and gravimetric techniques. When ion chromatography technique is used for sulfur content determination in coal and fuel oil, the precision of values expressed as the relative standard deviations (% RSD, n=10), were 1.47 % and 0.61 %, which has been understood as being much lower than those obtained by gravimetric standard methods, more precisely, 3.46 % for coals and 2.46 % for fuel oil. For biomass with a sulfur content about 10 times less than in coals and fuel oil, best results were obtained by ion – chromatography technique with the low limit of the measuring range much smaller than the limit reached by applying the gravimetric technique.

Solid waste laboratory samples homogeneity influence on analytical determination

The paper presents the influence of solid waste laboratory samples homogeneity on the determinations quality of calorific value and carbon content. Laboratory tests were conducted for a sample of mixed solid wastes (biomass, textile, plastic). The waste laboratory sample was prepared for physico-chemical characterisation by using basic methods, mass and particle size-reduction of components. Particle size-reduction of components was carried out using two laboratory mills: Retsch Rotor Beater Mill SR 300, and Retsch Vibratory Disc Mill RS 200. Laboratory sample was prepared in two versions. In the first version (V1) particles size reduction took place by passing a 2 mm sieve through the rotor beater mill Retsch SR 300. The plastic component of the waste was not fully integrated into the sample. In the second version (V2) the waste sample obtained in the first version was first pulverized in the Retsch Vibratory Mill RS 200, followed by a comminution of the particles to diameters passing a 0,5 mm sieve through the Rotor Beater Mill Retsch SR 300. In the second version the sample was visibly homogeneous. Laboratory sample homogeneity influence was highlighted by determining calorific value and carbon content of the waste sample prepared in the two versions. Following laboratory tests the results for carbon content and calorific value were within the repeatability limits imposed by the standardized methods for the second laboratory sample version.

Emissions of greenhouse gases from the livestock sector

In the livestock sector, the livestock activity involves also an air pollution with greenhouse gases, the main pollutants being methane, carbon dioxide and nitrogen protoxide. Depending on the farming system, the animal breed, the food supplied to the animals, and the manure management, various concentrations of gases with greenhouse effect may appear in the gaseous emissions. Emissions of gaseous pollutants from buildings where the animals are kept can pollute the atmosphere and can also affect the health of the farm workers. The natural ventilation of the stables has a major influence on the difficulty of determining the pollutant concentrations in the gaseous emissions, due to the inhomogeneity of the gas flow and the large variations in the pollutant concentrations at different points that are caused by the speed of the air movement through the venting holes and pollutant dispersion inside the building. This study presents the results obtained in a series of measurements of the levels of greenhouse gases at a dairy farm stable with natural ventilation. The equipment used for measurement was a portable gas chromatograph, Varian CP 4900. During the measurements, all the animals have been in the stable (they have not been taken to the pasture during that time).

Characterization of the chemical composition of atmospheric deposition

Atmospheric deposition means the total mass of pollutants which is transferred from the atmosphere to surfaces (e.g. soil, vegetation, water, buildings, etc.) in a given area within a given time. Is considered to be a major process that removes pollutants from the atmosphere and an important source of nutrients and contaminants for ecosystems. Trace elements, especially toxic metals deposited on plants and into soil or water, can cause substantial damage to the environment and human health due to their transfer and accumulation in food chains. This study aimed to determine the amount and the composition of dry deposition in a residential area in Bucharest, organized in summer of 2016, according toDirective 2004/107/EC transposed into Romanian legislation by Law No. 104/2011 regarding the ambient air quality. The dry deposition samples were collected in accordance with SR EN 15841-2010 Standard. The major elements ( Ca, K, Mg) and trace metals (Zn, Fe, Al, Ni, Mn, Cr, Cu, Pb and Cd) were determined by atomic absorption spectrometry equipped with a in graphite furnace and inductively coupled plasma optical emission spectrometry (ICP-OES), after acid digestion. Al and Fe were recorded as the dominant metallic elementsin dry deposition followed by Zn, Ni, Cu, Pb, and Cr. This study suggests that earth crust and anthropogenic activities such as motor vehicles were the main sources of dust fall in the study area.

MATHEMATICAL MODELING OF NOISE LEVEL IN THE WIND PARK AREA

In the actual period the environmental protection is a major problem to humanity. In most countries of the world are set to impose measures to limit pollution. International conventions were signed harmonizing these measures. Economic development entails environmental concerns in general and in particular the noise. In this paper are analyzed in terms of noise emission three wind parks in the county of Constanta. Wind energy has been used since ancient times earning a good tradition. In particular, a broader and widespread use of wind energy has many advantages for both technical nature (safe energy source to natural ecosystems, with a possible high overall efficiency, simplicity of construction and during installation) and economic (financial investment reduced operating costs and relatively low maintenance). Turbines for producing electricity are installed in areas with air currents present almost throughout the year. Also nearby wind parks are rural villages with a potential impact in terms of noise. Measurements were performed on each turbine noise wind parks belonging and the data obtained was performed mathematical modeling and drafting papers on noise dispersion in the areas studied.

RESEARCH ON THE RELATIONSHIP BETWEEN URBAN AIR POLLUTION AND NOISE LEVELS IN AREAS WITH HEAVY TRAFFIC

Despite being a less frequently considered type of environmental pollution, noise has a major negative impact on the quality of life in cities. As seen by an extensive survey of environmental noise, the commonest sources of urban noise are known to be transport, industry. Although many different types of pollution may be expected to show correlations, only a number of studies have focused on examining the relationships between street noise and ambient air quality and their combined impacts on the surrounding environment. Environmental issues are extremely complex and cover all sectors: economic, social and political. Accelerated urbanization of modern cities produced an urban environmental pollution, so that air quality can be affected. The paper presents some preliminary studies regarding the correlation between noise pollution and the concentrations specific pollutants road traffic. The measurements have been conducted at different distances from some very busy roads and crossroads in order to determine a pattern. The data have been processed with a statistical analysis program in order to establish if the noise level can be used to assess the urban air pollution generated by traffic. Most of the results indicate a good correlation between noises, specific pollutants road traffic. Noise level can be a good indicator for air pollution, especially for the situation when there is no need of a precise determination.