1,721,184 research outputs found
Greenhouse gas emissions and energy balance of biodiesel production from microalgae cultivated in photobioreactors in Denmark: a life-cycle modeling
Full text linkThe current use of fossil fuels is problematic for both environmental and economic reasons and biofuels are regarded as a potential solution to current energy issues. This study analyzes the energy balances and greenhouse gas emissions of 24 different technology scenarios for the production of algal biodiesel from Nannochloropsis cultivated at industrial scale in photobioreactors in Denmark. Both consolidated and pioneering technologies are analyzed focusing on strengths and weaknesses which influence the performance. Based on literature data, energy balance and greenhouse gas emissions are determined in a comparative 'well-to-tank' Life Cycle Assessment against fossil diesel. Use of by-products from biodiesel production such as glycerol obtained from transesterification and anaerobic digestion of residual biomass are included. Different technologies and methods are considered in cultivation stage (freshwater vs. wastewater; synthetic CO2 vs. waste CO2), harvesting stage (flocculation vs. centrifugation) and oil extraction stage (hexane extraction vs. supercritical CO2 extraction). The choices affecting environmental performance of the scenarios are evaluated. Results show that algal biodiesel produced through current conventional technologies has higher energy demand and greenhouse gas emissions than fossil diesel. However, greenhouse gas emissions of algal biodiesel can be significantly reduced through the use of 'waste' flows (nutrients and CO2) but there are still technical difficulties with both microalgae cultivation in wastewater as well as transportation and injection of waste CO2. In any way, a positive energy balance is still far from being achieved. Considerable improvements must be made to develop an environmentally beneficial microalgae biodiesel production on an industrial scale. In particular, different aspects of cultivation need to be enhanced, such as the use of wastewater and CO2-rich flue gas from industrial power plants. (C) 2015 Elsevier Ltd. All rights reserved
X Convegno dell'Associazione Rete Italiana LCA 2016. Life Cycle Thinking, sostenibilità ed economia circolare. Ravenna 23-24 giugno 2016
Full text linkLa Rete Italiana LCA è stata lanciata nel 2006 con l’obiettivo di favorire la diffusione della metodologia di Life Cycle Assessment attraverso la creazione di un network nazionale e l’organizzazione di convegni e seminari. Nel 2012 la Rete si è costituita in Associazione scientifica rafforzando il suo impegno per lo
sviluppo e l’adozione dell’approccio del ciclo di vita nell’implementazione dello sviluppo sostenibile.
Tra le iniziative intraprese dalla Rete Italiana LCA, particolarmente rilevante è il Convegno nazionale annuale al quale prendono parte le più importanti realtà del settore operanti sul tema del Life Cycle Assessment. Il Convegno quest’anno si svolge con il patrocinio di Ministero dell’Ambiente e della Tutela del Territorio e del Mare, SETAC Italian Branch, Società Chimica Italiana, Università degli Studi di Bologna Campus di Ravenna e Fondazione Flaminia per l’Università in Romagna; usufruisce,
inoltre, della sponsorizzazione di Cassa di Risparmio di Ravenna, Thinkstep e YARA Italia.
Il tema del Convegno annuale 2016 è il ruolo del Life Cycle Thinking nel supportare l’adozione di scelte operative e strategiche efficaci nella definizione e valutazione di prodotti/processi/servizi ambientalmente e socialmente sostenibili e nell’implementazione dell’economia circolare. In tal senso il Convegno fa il punto sulle iniziative internazionali e sui più recenti sviluppi nazionali connessi all’evoluzione metodologica e all’applicazione dell’approccio del ciclo di vita, con un particolare focus sulle novità legislative di recente approvate in Italia. In particolare, lo schema nazionale volontario Made Green in
Italy (art. 21 Legge 221/15) e le linee guida attuative in materia di offerta economicamente più vantaggiosa (art. 95 del Codice degli Appalti e delle Concessioni, D.lgs n. 50/16) rafforzano il ruolo del “Life Cycle Thinking” nel panorama nazionale
Modern accumulation rates and sources of organic carbon in the NE Gulf of Cadiz (SW Iberian Peninsula)
No full textOrganic carbon (OC) content, elemental (C/N) and isotopic (d13C) composition of organic matter (OM) constrain relative contributions from both marine and terrestrial sources to modern sediments in the NE Gulf of Cadiz (GoC) shelf. C/N and (d13C) indicate a transition from a dominantly marine to a terrestrial input of OM deposited in Bay of Cadiz and the Guadalquivir prodelta. OC and mass accumulation rates (MARs, based on bulk density and 210Pb-derived sediment MAR) suggest that labile OM from primary productivity accounts for the low OC content and burial rates in sediments in the NE GoC shelf
Life Cycle Assessment of biodiesel production from microalgae: a case study in Denmark
No full textThis study provides different scenarios on the eco-sustainability of the implementation of biodiesel production from microalgae cultivated in PBRs and located in Denmark on an industrial scale. LCA is the tool used to perform the assessment. The best available technologies for algal biodiesel production in PBRs were analyzed and compared. Each scenario has been compared also with diesel production performances. Finally, an evaluation of the parameters which most affect biodiesel production has been performed. The processes of algal biodiesel production taken into account are: cultivation, harvesting, the drying phase, oil extraction, transesterification, anaerobic digestion of residual biomass and the use of glycerol obtained from transesterification
Waste management in Forlì-Cesena province: Life Cycle Assessment (LCA) of Forlì incinerator
No full textThis work assesses the environmental impact of a municipal solid waste incinerator with energy recovery situated in Forlì-Cesena province (Emilia-Romagna region, Italy). The methodology used is Life Cycle Assessment (LCA). This plant, opened in 2008, is able to submit 120000 t/year of waste. It uses dry flue gas abatement equipment, composed of a couple of fabric filters and lime and activated carbon spraying. It also includes a cogeneration plant, i.e. it simultaneously generates heat and power by a heat engine. As the plant tries to produce as few residues as possible, and it recovers a significant amount of energy, it already applies the best technologies available in waste treatment. This is why this study focuses mainly on the fate of the solid residues produced during incineration
Environmental assessment of wheat and maize production in an Italian farmers' cooperative
No full textStandard ISO Life Cycle Assessment methodology was applied to the production of wheat and maize in an Italian farmers' cooperative, with the aim to assess the potential environmental impacts throughout the life cycle of these crops as well as to identify the hotspots in the production chains. The functional units were 1 tonne of wheat and maize, respectively and system boundaries were from cradle to cooperative's gate, including the agricultural production, the transport to the cooperative, and the cleaning as well as storage phases. Specific primary data collected both at farm and cooperative's premises, were used in the study. The results, according to ILCD impact assessment methods, show that the major hotspot for both cereals in all impact categories is the agricultural phase, due to fertilizers and pesticides use. Finally, a sensitivity analysis was performed, using different methods for the calculation of on-field nitrogen and pesticides emissions, in order to assess their effects on LCA results
A dose calculation model application for indoor exposure to two-layer walls gamma irradiation: The case study of ceramic tiles
No full textA calculation model for determining the indoor dose due to building materials with significant concentration of radioactivity has been applied to the case study of ceramic tiles; the model allows the contribution of bearing walls and wall covering materials to be calculated. The model is implemented in FORTRAN 77 and provides a quantification of the gamma radiation field (in terms of external dose rate in air, nGyh-1) inside a room with known dimensions. Application model results have been validated both by comparison with the results obtained by other authors and by experimental measurements. Model sensitivity and performances have been analysed and lastly the case studies focused on ceramic tiles have been proposed
Freshwater ecotoxicity characterisation factor for metal oxide nanoparticles: A case study on titanium dioxide nanoparticle
Full text linkThe Life Cycle Assessment (LCA) methodology is widely applied in several industrial sectors to evaluate the environmental performance of processes, products and services. Recently, several reports and studies have emphasized the importance of LCA in the field of engineered nanomaterials. However, to date only a few LCA studies on nanotechnology have been carried out, and fewer still have assessed aspects relating to ecotoxicity. This is mainly due to the lack of knowledge in relation on human and environmental exposure and effect of engineered nanoparticles (ENPs). This bottleneck is continued when performing Life Cycle Impact Assessment, where characterization models and consequently characterization factors (CFs) for ENPs are missing. This paper aims to provide the freshwater ecotoxicity CF for titanium dioxide nanoparticles (nano-TiO2). The USEtox™ model has been selected as a characterisation model. An adjusted multimedia fate model has been developed which accounts for nano-specific fate process descriptors (i.e. sedimentation, aggregation with suspended particle matter, etc.) to estimate the fate of nano-TiO2 in freshwater. A literature survey of toxicity tests performed on freshwater organism representative of multiple trophic levels was conducted, including algae, crustaceans and fish in order to collect relevant EC50 values. Then, the toxic effect of nano-TiO2 was computed on the basis of the HC50 value. Thus, following the principle of USEtox™ model and accounting for nano-specific descriptors a CF for the toxic impact of freshwater ecotoxicity of 0.28PAFdaym3kg-1 is proposed
Combining life cycle assessment and qualitative risk assessment: The case study of alumina nanofluid production
No full textIn this paper the authors propose a framework for combining life cycle assessment (LCA) and Risk Assessment (RA) to support the sustainability assessment of emerging technologies. This proposal includes four steps of analysis: technological system definition; data collection; risk evaluation and impacts quantification; results interpretation. This scheme has been applied to a case study of nanofluid alumina production in two different pilot lines, "single-stage" and "two-stage". The study has been developed in the NanoHex project (enhanced nano-fluid heat exchange). Goals of the study were analyzing the hotspots and highlighting possible trade-off between the results of LCA, which identifies the processes having the best environmental performance, and the results of RA, which identifies the scenarios having the highest risk for workers. Indeed, due to lack of data about exposure limits, exposure-dose relationships and toxicity of alumina nanopowders (NPs) and nanofluids (NF), the workplace exposure has been evaluated by means of qualitative risk assessment, using Stoffenmanager Nano. Though having different aims, LCA and RA have a complementary role in the description of impacts of products/substances/technologies. Their combined use can overcome limits of each of them and allows a wider vision of the problems to better support the decision making process
Biorefining of high ligno-cellulosic waste biomass via pyrolysis coupled with anaerobic digestion. An LCA study
No full textThe sustainable processing of biomass into a spectrum of products and energy is the goal of a biorefinery. Sustainability is key in this process and all biorefineries should be designed for sustainability along the entire value chain.
A laboratory-scale plant has been built by the University of Bologna, coupling pyrolysis and anaerobic digestion, in order to treat high ligno-cellulosic waste biomass.
This technology set can bring a wider range of exploitable residual biomasses in anaerobic digestion.
A life cycle assessment has been conducted on the use of corn stover in this experimental plant. The assessment included changes in land-use and soil carbon stock, biochar application to agricultural soils, biomass collection and pre-treatment, and biochar valorization as fertilizer and for carbon storage.
The system is compared to a fossil reference system providing the same set of products.
Results show that the process can yield a net energy gain and reduce GHG emissions, but high variability affects some key parameters, such as the energy required by the pyrolyzer and the biogas output from the anaerobic digester. As for the carbon balance, a relevant contribution is given by carbon storage in biochar
- …
