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Influence of Different Pretreatments on Anaerobically Digested Sludge Characteristics: Suitability for Final Disposal
2009
Carballa, Marta | Omil, Francisco | Lema, Juan M.
The debate on sludge recycling and disposal has been recently a target of growing interest due to the expressed concern about the potential risks of its agricultural use on human health and the environment. This fact has led to revisions in government policy and regulations and many novel treatment processes have been proposed in order to make the recycling and reuse of sewage sludge sustainable. In this work, the use of some pretreatments (alkaline, thermal, and ozonation) combined with conventional anaerobic digestion has been assessed on digested sludge quality in terms of pathogens, dewatering properties, heavy metals, and organic pollutants. All pretreatments proved to be efficient to reach the requirements proposed in the Working Document on Sludge prepared by the European Commission (CEC, Council Directive of 27 April 2000 on Working Document on Sludge--third draft. Brussels: European Commission DG Environment. Retrieved from http://ec.europa.eu/environment/waste/sludge/pdf/sludge_en.pdf, 2000a) and also those established by the U.S. Environmental Protection Agency (EPA, Standards for the disposal and utilization of sewage sludge, part 503. Retrieved from http://www.epa.state.il.us/public-notices/2004/lincoln-trails-mhp/draft-permit.pdf, 1993).
اظهر المزيد [+] اقل [-]Chemical Composition of PM₁₀ and PM₂.₅ and Seasonal Variation in South Brazil
2009
Teixeira, Elba Calesso | Meira, Lindolfo | Santana, Eduardo Rodrigo Ramos de | Wiegand, Flavio
This paper presents experimental data on particulate matter (PM₁₀ and PM₂.₅) in the atmosphere of Candiota--South Brazil. Samples were collected using stacked filter units equipped with polycarbonate filters, which separate particles into two fractions: coarse 10-2.5 μm and fine <2.5 μm. The particulate matter was collected from January 2003 to September 2004 at three sampling sites: Acegua, 8 de Agosto, and Três Lagoas. The collected material was analyzed for Na, Mg, Al, Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, Br, Mo, Hg, and Pb, using particle-induced X-ray emission technique. Seasonal variation of the chemical elements with the size fraction was assessed. The elements K, Ca, Si, Ti, Fe, and Mn showed similar seasonal variability in the fine and coarse fractions with a low enrichment factor (<1.0) in both fractions, except for Mn and K, indicating common sources (soil dust, fly ash). Chemical species showing seasonal variability and high values of enrichment factor in fine fractions may indicate an anthropogenic origin.
اظهر المزيد [+] اقل [-]A Valuation of the Influence of Particulate Atmospheric Aerosol in Constructions of the Cultural and Architecture Patrimony of the Urban Area of Castellon (NE, Spain)
2009
Jordan, M. M. | Sanfeliu, T. | Gómez, E. T. | Pallarés, S. | Vicente, A. B.
The constructions of Cultural and Architecture Patrimony are influenced by pollutants. Many of degenerative processes in the materials which constitute them have their origin in pollutants. That is the reason why a physical-chemical characterisation of the particulate pollutants in the air has been carried out. The deposition and, as a consequence of that, the interaction of the pollutants with the different materials of the monuments depend on the reactivity of the chemical elements that form the atmospheric particulate. Studies of both, bulk dust deposition and total suspended matter, a mineralogical and chemical characterisation of them have been made. Lastly, starting from these data, it can be established that the interactions and degenerative processes are taking place in the monuments of the studied locations. In the present work, the methodology carried out in the study of the particulate atmospheric pollutants, which are capable of accumulating on monuments and buildings with artistic and historical interest in the area of Castellon, is displayed. By means of a network of captors, important samples of sedimentary and suspension atmospheric pollutants, total suspension particles (TSP) were obtained. Firstly, by gravimetric methods, we have obtained the concentration levels of these kinds of pollutants in milligrams per day in busk dust samples and micrograms per cubic meter in TSP. Due to the fact that the corrosivity of these pollutants fundamentally depends on their compositions, the study has been completed with a mineralogical and chemical characterisation. By X-ray diffraction and scanning electron microscopy, we have analysed the particles of the two kinds of samples. The chemical analysis was carried out by inductively coupled plasma-atomic spectroscopy and inductively coupled plasma-mass spectrometry (multielement analysis techniques) in TSP samples and in the soluble fraction of the depositing particulate matter. The results have shown as main compounds: clay minerals, calcite, and carbonaceous matter coming from non-perfect combustion of vehicles. The chemical analysis indicates a high Ca/S ratio and high levels of concentration in chemical elements associated to this representative industrial cluster of ceramics industry in Europe.
اظهر المزيد [+] اقل [-]Using Factor Analysis to Characterise Historical Trends of Trace Metal Contamination in a Sediment Core from the Tagus Prodelta, Portugal
2009
Mil-Homens, Mário | Branco, Vasco | Lopes, Cristina | Vale, Carlos | Abrantes, Fatima | Boer, Wim | Vicente, Maria
A box-core 3576 (PO287-26-1B) collected from the Tagus Prodelta in 2002 was analysed for organic carbon, ²¹⁰Pb, ²²⁶Ra, major (Al, Fe, Ca, Ti, Mg and Mn) and trace elements (Ba, Hg, Cr, Cu, Li, Ni, Pb, Sb, Sn, Sr, and Zn). Maximum concentrations of contaminants in ²¹⁰Pb-dated samples were reached in the decades between 1960 and 1980, followed by a slightly decrease in up-core metal trends. Trace metal concentrations increased in the bottom of the core (²¹⁰Pb dated as 1925) to maximum values during the 1970s. Factor analysis of geochemical data was used to reduce the 18 variables into four factors that reveal distinct origins or accumulation mechanisms controlling the chemical composition in the study area. Changes in the dominance of these factors through the time indicate not only changes in industrial activity, but also the increase of biological productivity towards the present.
اظهر المزيد [+] اقل [-]The astysphere and urban geochemistry--a new approach to integrate urban systems into the geoscientific concept of spheres and a challenging concept of modern geochemistry supporting the sustainable development of planet earth
2009
Norra, Stefan
Background, aim, and scope In 1875, the geoscientist Walter Suess introduced several spheres, such as the lithosphere and the atmosphere to promote a comprehensive understanding of the system earth. Since then, this idea became the dominating concept for the understanding of the distribution of chemical elements in the system earth. Meanwhile, due to the importance of human beings on global element fluxes, the term anthroposphere was introduced. Nevertheless, in face of the ongoing urbanization of the earth, this concept is not any more adequate enough to develop a comprehensive understanding of global element fluxes in and between solid, liquid, and gaseous phases. This article discusses a new concept integrating urbanization into the geoscientific concept of spheres. Main features No geological exogenic force has altered the earth's surface during the last centuries in such an extent as human activity. Humans have altered the morphology and element balances of the earth by establishing agrosystems first and urban systems later. Currently, urban systems happen to become the main regulators for fluxes of many elements on a global scale due to ongoing industrial and economic development and a growing number of inhabitants. Additionally, urban systems are constantly expanding and cover more and more former natural and agricultural areas. For nature, urban systems are new phenomena, which never existed in previous geological eras. The process of the globe's urbanization concurrently is active with the global climate change. In fact, urban systems are a major emitter for climate active gases. Thus, beside the global changes in economy and society, urbanization is an important factor within the global change of nature as is already accepted for climate, ecosystems, and biodiversity. Results Due to the fact that urbanization has become a global process shaping the earth and that the urban systems are globally cross-linked among each other, a new geoscientific sphere has to be introduced: the astysphere. This sphere comprises the parts of the earth influenced by urban systems. Accepting urbanization as global ongoing process forming the astysphere comprehensively copes with the growing importance of urbanization on the creation of present geologic formations. Discussion Anthropogenic activities occur mainly in rural and urban environments. For long lasting periods of human history, human activities mainly were focused on hunting and agriculture, but since industrialization, urbanized areas became increasingly important for the material and energy fluxes of earth. Thus, it seems appropriate to classify the anthroposphere into an agriculturally and an urban-dominated sphere, which are the agrosphere (Krishna 2003) and the astysphere (introduced by Norra 2007). Conclusions We have to realize that urban systems are deposits, consumers, and transformers of resources interacting among each other and forming a network around the globe. Since the future of human mankind depends on the sustainable use of available resources, only a global and holistic view of the cross-linked urban systems forming together the astysphere provide the necessary geoscientific background understanding for global urban material and energy fluxes. If we want to ensure worth-living conditions for future generations of mankind, we have to develop global models of the future needs for resources by the global metasystem of urban systems, called astysphere. Perspectives The final vision for geoscientific research on the astysphere must be to design models describing the global process of urbanization of the earth and the development of the astysphere with respect to fluxes of materials, elements, and energy as well as with respect to the forming of the earth's face. Besides that, just from the viewpoint of fundamental research, the geoscientific concept of spheres has to be complemented by the astysphere if this concept shall fully represent the system earth.
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