86,618 research outputs found
Comparison of single-stage and two-stage anaerobic Co-Digestion of food waste and activated sludge for hydrogen and methane production
No full textIn this study, the co-digestion of food waste and activated sludge was evaluated in a two-stage anaerobic system and compared to the traditional single-stage process. The two-stage system was composed by two reactors connected in series able to perform the fermentative and the methanogenic phases separated. Experiments were carried out in semi-continuous mode under mesophilic conditions (37 °C). The two-stage technology achieved an overall improvement of the anaerobic performances. Results highlighted an increase in biogas production and volatile solids degradation of 26% and 9%, respectively. Considering the whole two-stage system, i.e. the sum of the biogas productions of the first and the second digester, these percentages increased up to 35.0%. Concerning gas quality, the two-stage system achieved a hydrogen rich biogas in the first fermentative reactor and an improvement of methane content in the second methanogenic digester. The average methane content shifted from 61.2% to 70.1%. The highest methane production of the two-stage process was due to improved substrate hydrolysis, with increased amounts of volatile fatty acids made readily available in the second stage
Centralization of wastewater treatment in a tourist area: A comparative LCA considering the impact of seasonal changes
No full textNowadays, environmental protection has become a topic of primary importance, and the interest in wastewater treatment plants (WWTPs) has increased due to the need for a paradigm shift from linear to circular economy. The centralization level of wastewater infrastructure is the basis for a successful system. The aim of this study was to investigate the environmental impacts generated from the centralized treatment of wastewater in a tourist area in central Italy. The combined use of BioWin 6.2 simulation software and life cycle assessment (LCA) methodology was implemented to evaluate the potential connection of a small decentralized WWTP to a medium-size centralized facility. Two different scenarios (decentralized system, corresponding to the current situation, and centralized) were evaluated in two separate periods: high season (HS), corresponding to the main tourist season, and low season (LS), which is the period before the main tourist season. Two sensitivity analyses were conducted, assuming different N2O emission factors, and considering the period at the end of tourist season, respectively. Although with modest advantages (up to −6 % in pollutant emissions), WWTP connection was the best management option in 10 out of 11 indicators in HS, and 6 out of 11 categories in LS. The study showed that wastewater centralization was promoted by scale factors in HS, as the most impactful consumptions decreased as the degree of centralization increased; on the other hand, the decentralized system was less penalized in LS, as small WWTP was less stressed and energy consuming in this period. Sensitivity analysis confirmed the results obtained. Site-specific conditions can lead to conflicting circumstances, as key parameters may have different behaviors depending on seasonal variations, and the degree of centralization in tourist areas should be addressed by distinguishing separate periods, based on changes in tourist flows and pollution loads
Biomedical processing of polyhydroxyalkanoates
No full textThe rapidly growing interest on polyhydroxyalkanoates (PHA) processing for biomedical purposes is justified by the unique combinations of characteristics of this class of polymers in terms of biocompatibility, biodegradability, processing properties, and mechanical behavior, as well as by their great potential for sustainable production. This article aims at overviewing the most exploited processing approaches employed in the biomedical area to fabricate devices and other medical products based on PHA for experimental and commercial applications. For this purpose, physical and processing properties of PHA are discussed in relationship to the requirements of conventionally-employed processing techniques (e.g., solvent casting and melt-spinning), as well as more advanced fabrication approaches (i.e., electrospinning and additive manufacturing). Key scientific investigations published in literature regarding different aspects involved in the processing of PHA homo-and copolymers, such as poly(3-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate), and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), are critically reviewed
Planning the centralization level in wastewater collection and treatment: A review of assessment methods
No full textCentralized wastewater treatment has been the favorite wastewater treatment strategy until a few decades ago, in order to exploit each possible scale economy. Nowadays, water stress and resource scarcity, due to population growth and climate change, call for water reuse and resource recovery, and these goals do not often find in centralization the best solution. Today, the reuse of reclaimed water can take place at different levels and rep-resents an option of primary importance; therefore, in some cases, centralized systems may be economically and environmentally unsustainable for this additional purpose, and the search for the optimal infrastructure centralization degree must take into account these goals. This review analyzes studies that investigated the search of the best centralization level of wastewater collection and treatment, focusing on the methodologies applied to take the decision and highlighting strengths and weaknesses of the different approaches and how they have evolved over time. The final goal is to guide planners and decision-makers in choosing and handling the most suitable method to assess the centralization level of wastewater infrastructures, based on the objectives set out. The reviewed studies cover a period of twenty years. The differences found along this time span show an ongoing paradigm shift towards hybrid systems, which combine centralized and decentralized wastewater treatments that promote the storage of treated water and various forms of local water reuse and resource re-covery. The protection of human health and the environment (which primarily promotes water reuse and resource recovery) has become the main challenge of wastewater treatment systems, that will presumably improve further their economic, social and environmental sustainability to achieve urban development in the context of the water-energy-food security nexus
Rumen-protected choline supplementation in periparturient dairy goats: effects on liver and mammary gland
No full textThe current study investigated the effects of supplementing rumen-protected choline (RPC) on metabolic profile, selected liver constituents and transcript levels of selected enzymes, transcription factors and nuclear receptors involved in mammary lipid metabolism in dairy goats. Eight healthy lactating goats were studied: four received no choline supplementation (CTR group) and four received 4g RPC chloride/day (RPC group). The treatment was administered individually starting 4 weeks before expected kidding and continuing for 4 weeks after parturition. In the first month of lactation, milk yield and composition were measured weekly. On days 7, 14, 21 and 27 of lactation, blood samples were collected and analysed for glucose, beta-hydroxybutyrate, non-esterified fatty acids and cholesterol. On day 28 of lactation, samples of liver and mammary gland tissue were obtained. Liver tissue was analysed for total lipid and DNA content; mammary tissue was analysed for transcripts of lipoprotein lipase (LPL), fatty acid synthase (FAS), sterol regulatory binding proteins 1 and 2, peroxisome proliferator-activated receptor gamma and liver X receptor alpha. Milk yield was very similar in the two groups, but R PC goats had lower (P < 0.05) plasma beta-hydroxybutyrate. The total lipid content of liver was unaffected (P = 0.890), but the total lipid/DNA ratio was lower (both P < 0.05) in RPC than CTR animals. Choline had no effect on the expression of the mammary gland transcripts involved in lipid metabolism. The current plasma and liver data indicate that choline has a positive effect on liver lipid metabolism, whereas it appears to have little effect on transcript levels in mammary gland of various proteins involved in lipid metabolism. Nevertheless, the current results were obtained from a limited number of animals, and choline requirement and function in lactating dairy ruminants deserve further investigation
Environmental impacts of dry anaerobic biorefineries in a Life Cycle Assessment (LCA) approach
No full textThe organic fraction of municipal solid waste (OFMSW) represents the 34% of European waste and the overall share is going to increase since separate collection will be implemented across the member states. There is still lack of studies on environmental impacts of dry anaerobic biorefineries applying innovative solvents to produce biopolymers (e.g., polyhydroxyalkanoates – PHA) from the OFMSW. A comparative Life Cycle Assessment (LCA) analysis was applied to assess the environmental impacts of a conventional management strategy to recover biomethane and compost from the OFMSW with a dry anaerobic biorefinery recovering biomethane, fertilizers and PHAs. Four approaches to recover PHAs were included in the study, comprising two innovative and environmentally sustainable extraction methods (i.e., solvent extraction with ethyl acetate (EA) and ionic liquids (ILs)). The inventory data were derived from an Italian case study plant, while the data for modelling the PHA selection/accumulation and PHA extraction processes were retrieved from the literature. The comparison revealed that, at the current technological readiness level (TRL), the conventional management strategy has better environmental performances than the novel approach producing PHAs. For example, biomethane recovery, for which a substitution with natural gas was assumed, showed the highest avoided impacts for abiotic depletion of fossil fuel (65.5%), global warming (57.4%) and ozone layer depletion (65.4%) categories. PHA recovery scenarios showed high environmental impacts in all categories linked to natural resource depletion. PHA extraction with EA proved to be the most environmentally sustainable and promising technique towards an industrial application
La lattoferrina come componente bioattiva del latte : valutazione dell’attività biologica mediante l’impiego di cellule epiteliali di ghiandola mammaria bovina in vitro
No full textNutrition in mammary gland health and lactation : advances over eight Biology of Lactation in Farm Animals meetings.
No full textOver the years, numerous studies have investigated the mechanisms controlling nutrient availability and metabolism in the mammary gland and how dietary interventions can influence these processes. The development of in vivo and in vitro systems made it possible to explore the trafficking and metabolic fate of nutrients and how these are influenced by hormones. To improve the quality and safety of milk products, attention has focused on improving animal health in general and mammary gland health in particular and also on enhancing the milk content of natural bioactive milk components that promote the health of human neonates and adults. In the past, attempts to probe the relationship among nutrition, animal health, and animal products were limited to administering single dietary components and investigating their biochemical and metabolic effects. Today, we have genomics, proteomics, and related technologies that allow us to pursue more holistic investigational strategies. These new technologies are providing new insights into interactions among nutrition, lactation, and product quality. The aim of this paper is to review advances in nutritional support of mammary gland function and health as presented in 14 yr of Biology of Lactation in Farm Animals (BOLFA) meetings
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