The article presents a classification methodology of regional development in Romania (41 counties and Bucharest) using a set of data registered in 2019 by the National Institute of Statistics. Several indicators cover information related to the population (the migration, permanent residence, and education), local investments, private turnover, and investments in water supply and sewerage systems, including waste management. After applying the statistical tests, the separation of the counties was done in three classes, the delimitation indicating a high percentage of 59.5% of regions that have low values of the selected indicators. These regions require major investments that will lead to rising living standards, and the emergence of new jobs, driving down the average age of the population. 21.4% of the regions present an average level of the analyzed indicators while only 19% registered the highest values of the parameters, indicating urban agglomerations and a high level of industrial development.
Absorption of methylene blue from aqueous solutions on activated coal CAN-9: kinetics and equilibrium studies
Authors: TUDOR LUPASCU, MIHAIL CIOBANU, ELENA CULIGHIN
The adsorption of methylene blue and the kinetics of adsorption of aqueous solutions on activated carbon CAN-9, obtained from walnut shells by chemical activation with orthophosphoric acid were studied. It has been shown that the adsorption isotherm of methylene blue from aqueous solutions on CAN-9 in the linear coordinates of the Langmuir model is a straight line (R = 0.99427) and is of the Langmuir type. The kinetics of adsorption of methylene blue on CAN-9, measured at two initial concentrations, showed an increase in Kint and C values with the increase of the initial concentrations. The process of intra-particular diffusion occurs in only one stage and takes place in the mesopores.
New tool for Gram-negative and Gram-positive bacterial strains differentiation through GC-MS direct identification of exogenous VOC metabolites in headspace vials
In this paper, a chromatographic method for the determination of volatile organic compounds (VOCs) as a tool for Gram-positive and Gram-negative bacterial strains identification was described. Direct Headspace gas chromatography coupled with mass spectrometry (Headspace-GC-MS) has been used for the qualitative determination of VOCs emitted by certain bacterial strains (Salmonella Typhimurium, Escherichia coli, Serratia rubidae, Staphyloccocus aureus, Enterococcus casseliflavus, and Enterococcus faecalis). In the first stage of the study, pathogenic bacteria were cultured in broth-specific liquid culture medium directly (lauryl sulfate broth) into headspace vials. Subsequently, the VOC emissions were analyzed by airborne screening in the headspace vials. Thus, the objective was to analyze all the resulting volatile organic compounds in order to select only those compounds which can be exclusively associated with specific pathogenic bacteria. Qualitative analysis by Headspace-GC-MS has proven to be a non-invasive, accurate, and fast method for identifying certain bacterial strains, based on VOCs emission. A considerable number of volatile organic compounds have been determined in the headspace air, a significant difference being observed between the VOCs emitted by bacterial cultures compared to the culture medium but also between the types of bacterial cultures themselves.
The study presents preliminary results, which prove that the identification of the studied pathogenic bacteria is possible, based on the determination of certain types of VOCs in the headspace air of these cultures. This method can be used successfully for the rapid identification of bacterial culture types compared to classical methods.
Mineral precipitates from mine water as adsorbents -Part I- Site-specific characterization of natural deposits
Authors: LAURENTIU RAZVAN DINU, VALERIU ROBERT BADESCU, GABRIELA GEANINA VASILE, IONUT CRISTEA, NICOLETA MIRELA MARIN, ECATERINA ANCA SERBAN
Secondary minerals, and mixtures of Fe-Al compounds such as oxohydroxy and hydroxosulfates can be naturally generated from mine water in response to oxidation /bio-oxidation, mixing, evaporation and neutralization processes. Deposits observed in significant quantities, with very high iron content, from the mining perimeters of Certej-Coranda, Rosia Montana, and Boita Hateg were sampled and characterized. Schwertmannite and Goethite can function as adsorbents after drying or further processing. In both cases, the chemical analysis of the product is important in order to promote it to potential users. A preliminary evaluation of the adsorption capacity for As(III) was performed for the original material and for products obtained after calcination. Depending on calcination temperature, adsorption capacity decreases, and a leveling effect can be observed, most probably due to pore sinterizing and transformation to hematite, irrespective of the initial mineral.
Lanthanides as impurities in the Bayer production cycle of the aluminum hydroxide
from Sierra Leone bauxite
Authors: LIDIA KIM, GHEORGHE DOBRA, RALUCA ISOPESCU, SORIN ILIEV, LUCIAN COTET, ALINA BOIANGIU, GINA ALINA CATRINA, LAURENTIU FILIPESCU
This paper is describing a careful study on content and distribution of rare elements in the fluid and solid phases involved in dry and classified aluminum hydroxide production through Bayer process at Alum SA, Tulcea, Romania. The source of rare elements in Bayer process is the bauxite from Sierra Leone, a particular type of aluminous goethite-lateritic bauxite, not fully studied yet. Rare earths elements are fairly abundant in the nature, but their distribution is very large, encompassing hundreds of types of minerals where rare element appears as minor crystalline and amorphous compounds, solid solutions, or as ions adsorbed on the surface of common natural rocks. This study data show that Sierra Leone bauxite has only a small content in rare elements. Mainly, only the scandium and cerium concentrations (44.84 mg/kg and 11.49 mg/kg in bauxite residue) may reach the expected values required for eventually valorization. On the Bayer cycle, the rare metals enter with bauxite and concentrate in bauxite residues. Solubility of the rare element compounds in the Bayer process fluid phases is close to zero. In the final product, the aluminum hydroxide dried, milled and classified grades, the rare metals appear only as occlusion contaminants.
Physical mechanical and acoustic properties for composite materials made from construction and demolition waste
Authors: MIHAI BRATU, CORNEL DAN, VALENTIN STANCU, DANIEL CIOROIANU, COSMIN DUMITRESCU, DORIN BABEU, VALERIU DANCIULESCU
Environmental protection is an essential human problem and that is why most countries in the world are taking measures to limit it. As we know, pollution is contamination with materials that damage health, quality of life, or the natural functioning of ecosystems. Although some environmental pollution is a result of the action of nature, most are caused by human activity. The disposal of waste from various industrial processes affects the quality of the environment. A particular current problem with environmental pollution is waste as a whole, including construction and demolition waste. Another current problem is noise pollution with negative effects on humans. In this paper, these two problems are addressed through the valorization of these types of waste and the production of composite materials with sound-absorbing properties. Six types of construction and demolition wastes are used and subjected to physical-chemical analysis to determine their moisture content, particle size, and chemical composition. Through an optimized technological process, composite materials were obtained and their sound absorption capacity was determined.
Concentration versus number of particles in the assessment of air pollution with particulate matters
Authors: VALERIU DANCIULESCU, ANDREEA COZEA, ELENA BUCUR, GHEORGHITA TANASE, MIHAI BRATU
In this paper, an assessment study was performed regarding air pollution with particulate matters including submicron particles. The evaluation of the contamination level was performed at a textile production unit in Pascani, Romania, which produces polyester knitwear. In the study, automatic determinations of total suspended particulate matters (TSP), PM 10, PM 2.5 and PM 1 (particle with nominal diameter <10 µm, <2.5 µm and <1 µm), and submicron particulate matters (0.25, 0.35, 0.50 and 0.70) were performed both outdoor, in the ambient air, and indoor (workplace) in the area of the knitting machines. The correlation between the mass concentrations of submicronic particles (µg/m 3) and the numerical concentrations (number of particles/m3) was study, too, for establish the most appropriate expression of the air pollution level with particulate matter. The results of the performed tests showed a level of ambient air pollution with particulate matters that exceed the limit values in the case of PM 2.5 and PM 10, the total suspended particulates still falling within the limits established by law. Likewise, in the case ofworkplace air, the level ofinhalable particulate matters (particles with nominal diameter <100 µm), the concentration is below the limit values. Regarding the way of expressing the concentration of air particles, in µg/m3 or in no. particles/m3 the tests indicated better representativeness of the pollution level if the concentration in µg m3 is expressed for the dimensional fractions with diameter ≥ 1 µm and in no. particles/m3 for particles with a diameter of ≤1 µm.
Geochemical assessment of soil and water in two protected areas from Valcea and Dolj Counties
The purpose of this paper was to assess the quality of environmental factors such as soil and water in some protected areas in Romania. The chosen case studies were the Preajba-Facai lake system from Dolj County and the Vanturarita Buila National Park from Valcea County. Highlighting the evolutionary aspects of the analyzed quality parameters (20 physical-chemical indicators) on a spatial-temporal scale aiming at establishing geochemical thresholds, is the final result of a larger project. The results presented in this article were obtained through seasonal monitoring involving water and soil sampling and laboratory analysis. All the results were interpreted in relation to the values in the specific environmental legislation, and following the field visits, additional information was brought, which contributed to a good knowledge of these regions. The areas, although protected, are influenced by the anthropogenic factor, which has a negative impact on the environment. In some cases, non-compliances were identified and validated by the analysis performed.
Comparative assessment of influent wastewater organic fractions
Authors: ELENA ELISABETA MANEA, COSTEL BUMBAC, VALERIU ROBERT BADESCU, LAURENTIU RAZVAN DINU, OLGA TIRON
Organic fractions assessment in influent wastewater is essential for designing the biological wastewater treatment plant. The characteristics of the influent organic load (readily biodegradable, biodegradable, or inert) and form of distribution (soluble/suspended) may induce the design and operational parameters of primary settlers and biological treatment step. The current work presents the comparative assessment of organic fractions in three wastewater samples evaluated experimentally through three different fractionation methodologies, respectively modified ATV-A131 guidelines, IWA methodology, and the Łomotowski-Szpindor methodology. The wastewater samples were collected from the influent of two municipal wastewater treatment plants. In all wastewater samples tested the biodegradable fractions SS or XS had the highest share in the total COD. This is consistent with the biodegradable character of municipal influents and the suitability for organic and advanced nutrient removal through biological processes. The amount of non-biodegradable fractions SI and XI, varied from 18 to 54% of total organic load, on momentary grab samples of studied influents.