196,182 research outputs found
Ecosustainable biomethane and fertilizerproduction through anaerobic co-digestionof animal manure and energy crops
No full textIn Italy and many European countries energy production from biomass is encouraged by strong economic subsidies so that renewable energy plants, anaerobic digestion plant producing biogas in particular, are getting large diffusion. Nevertheless, it is necessary to define the environmental compatibility as well as technological and economic issues dealing with the emerging renewable energy scenario. This evaluation should take into account global parameters as well as environmental impacts at regional and local scale coming from new polluting emissions. The environmental balances regarding new energy plants are of primary importance within very polluted areas such as Northern Italy where air quality limits are systematically exceeded, in particular for PM10, NO2 and ozone. The most important environmental shortcomings that should be solved or at least minimized as far as biogas production and utilisation are concerned are: 1. macro-pollutants emissions from biogas engine at the local scale and low fuel utilization index (biogas plants generally don't recover all thermal energy at disposal); 2. indirect GHG emissions, mainly involving post-methanation emissions from the digestate storage; 3. ammonia emissions from the storage and land spreading of digested materials, low fertilising efficiency of manure and digestate, nitrate contamination of groundwater. The described emissions and energy inefficiency could involve negative environmental balances at the local scale, conflicting with the possible benefits arising from biomass energy production. An alternative technological choice for biogas valorisation could be biomethane production (also called green gas) through biogas purification and upgrading processes in order to remove CO2 and trace components. Biomethane production and its injection into natural gas grid (or its use as a transport vehicle fuel) could bring about strong energy and environmental benefits such as higher energy efficiencies and lower specific emissions (district heating CHP units, combined cycle gas turbines, methane powered vehicles). The present study mainly aims at analysing biogas upgrading techniques under the aspects of energy consumptions and environmental sustainability, with a specific focus on minimizing methane losses from the process by means of suitable design and operative choices (temperature, pressures, sorbents, recirculation strategies, etc.) that are fully described and simulated. The considered upgrading techniques are based on the principles of physical and chemical absorption and pressure/vacuum swing adsorption (PSA). The analysis highlights that there are strong differences among the examined upgrading techniques, as far as specific sorbent flows, absorbing tower dimensions, methane losses, power required, recoverable heat and environmental impacts (use of resources, gaseous releases of odorous and polluting molecules, GHG balances) are concerned. In particular, all the analysed upgrading techniques could be designed in order to achieve very low methane slip, below 0.1%, except PSA for which methane losses are hardly reducible below 2%, even at very high energy consumptions. The actual range of methane slip for the considered technologies is 0.1÷5% whereas the energy consumption to upgrade biogas lies in the range 0.05÷0.54 kWhe/m3 of raw biogas. The following analysis reports also some economic evaluations including electric energy costs, thermal energy requirements, biomethane sale incomes and external costs due to environmental impacts of biogas production+upgrading techniques. Within the described cost-benefit approach, the best overall balances seems to be assured by absorption with DEPG and chemical absorption with MEA. Finally, the last part of the present work shows a technical analysis of a specific digestate treatment process that could help reaching both the reduction of GHG and ammonia emissions and, at the same time, the production of fertilizers. The present analysis therefore confirms that biogas/biomethane technology is absolutely ready and suitable to reach very high levels of productivity, efficiency and environmental performances at sustainable costs and the right technological approach could solve many environmental problems regarding nitrate contamination of groundwater, ammonia emissions and global warming issue
La grotte du Farné, près Bologne (Italie)
No full textBrizio M., Miniggio E. La grotte du Farné, près Bologne (Italie) . In: Bulletin de la Société d'anthropologie de Lyon, tome 2/1, 1883. pp. 123-132
Results of atmospheric dispersion model for the localization of a MSW incinerator
No full textThe present study reports the attempt to localize a MSW incinerator, starting from three proposed sites, on the basis of the atmospheric transport and dispersion modelling. The considered area, around Turin, in North-Western Italy, is characterized by a high percentage of hours of calm wind, so the choice of the atmospheric model is very important in order to have reliable and convincing results. In the present study we used the AERMOD model by the U.S. EPA, that is a hybrid atmospheric dispersion model which can treat the calm hours within a more restrained computational time with respect to Eulerian or Lagrangian models. The investigated issue is generally a very delicate and thorny argument because of the natural opposition of the people against this kind of plant. The first thing to do to treat the localization of a MSW incinerator is to calculate the concentrations at the ground level due to the emitted pollutants and to compare them to the air quality regulations; secondly, one can think about the possibility of building a district heating system or distributing technological vapour service to industrial users, avoiding the respective emission of pollutants. In practice, the concentrations at the ground level when the incinerator is placed in the three proposed sites are very comparable and, for each site, much smaller than the air quality regulations and the measured levels of the area. The best localization is then determined by the possibility of realising a large district heating system
The influence of different mixing heights on the ECOSENSE model results at a local scale
No full textThe ECOSENSE software has been created and applied as part of the European long term project called ExternE, a research program devoted to the assessment of external costs due to electricity production. The ECOSENSE model starts from the emission rates of a facility, calculates the yearly mean concentrations of the pollutants at the ground level on the basis of atmospheric dispersion models and characterises the subjects exposed to the pollutants in the considered area. After this, proper epidemiological exposure-response and toxicological dose-response functions are applied to determine the impact on the receptors. Finally, the methodology can monetise the calculated physical impact on the basis of selected economic evaluations. The aim of this study is to apply the software to real cases at a local scale and to compare the results based on different mixing height inputs, since the determination of this meteorological parameter is quite complex. Such a study is useful to have an idea of the sensitivity of the ECOSENSE model and make it a user-friendly instrument for administrations; this can help to create a harmonic approach to the problem of atmospheric pollution and impact evaluation. For specified facilities and meteorological conditions and, in particular, for a 100,000 t/y MSW incinerator, the mixing height can be approximated by a constant value of 1000 m throughout the year and the final results will have deviations that are lower than 10%
LCA of bioenergy chains in Piedmont (Italy): a case study to support public decision makers towards sustainability
No full textGiven the booming of bioenergy plants under construction in Piedmont, in Northern Italy, Life Cycle Assessment (LCA) was used in order to assist public decision-makers during the evaluation of new bioenergy projects. Local administrators are in fact worried that public incentives granted to bioenergy producers, regardless of the overall environmental performance, might not encourage technological innovation and eco-efficiency, or bring unwanted indirect environmental effects. A detailed LCA of bioenergy production from dedicated crops (maize, sorghum, triticale and miscanthus) and manure through anaerobic digestion and combined heat and power generation was carried out. The LCA model was particularly focused on the end-of-life of digestate and site-specific data related to the impact of adopted energy conversion technologies. It was confirmed that bioenergy is not automatically synonymous with sustainable energy, as the differences in terms of environmental performance can be remarkable. EROI (Energy Return on Investment) index was estimated to be 3-5. The potential in terms of GHG saving depends on several factors and it is heavily influenced by the reference non-renewable energy to be substituted. End-of-life of digestate was found to be crucial for acidification and eutrophication, but also for GHG emissions. Finally, particulates equivalent emissions were found to be very large in comparison to modern natural gas power plants
A study of melanoma in Eastern European migrants in Italy.
No full textCancer survival rates are lower in Eastern Europe. To describe, based on a single-centre database in northern Italy, clinical, histopathological, and prognostic features of melanoma in a migrant population from Eastern Europe.
MATERIALS & METHODS:
We retrospectively analysed data from 18,190 consecutive foreign patients who visited our institution, with 49 cases of melanoma from Eastern Europe. The control group was represented by 1,003 Italian melanoma patients diagnosed and followed at our centre during the same time period. Patients from Eastern Europe were mainly females with lower median age, without significant differences regarding primary melanoma site, relative to the control group. Diagnosis was made at the place of birth in 30.6% and in our centre for the remainder. Median Breslow thickness was greater (p = 0.0178), and aggressive histotypes (p = 0.0017) and ulcerated melanomas (p = 0.002) were significantly over-represented, particularly when diagnosed in the patients' native country. Disease was more advanced at diagnosis (p = 0.0001), regardless of the place of initial diagnosis (51% had a progressive disease within one year which rose to 80% if diagnosed before admission to our centre), and the percentage of patients who died within one year was significantly higher (p = 0.022), relative to the control group. Our study shows a poor prognosis for melanoma patients diagnosed in Eastern Europe. Moreover, for migrant populations moving from Eastern to Western European countries, financial difficulties, poor social integration, and language barriers, with consequent late access to healthcare facilities, may account for a worse prognosis
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