1,721,041 research outputs found
A human health toxicity assessment of biogas engines regulated and unregulated emissions
Full text linkThe aim of the work is to evaluate the damage to human health arising from emissions of in-operation internal combustion engines fed by biogas. The need of including also unregulated emissions like polycyclic aromatic hydrocarbons (PAHs), aldehydes and dioxins and furans is twofold: (i) to cover the lack in biogas engine emissions measurements and (ii) to complete the picture on biogas harmfulness to human health by identifying the substances with the highest impact. To this purpose, an experimental campaign is conducted on six biogas engines and one fed by natural gas all characterised by an electric power of 999 kWel. Collected data are used to perform an impact analysis on human health combining the Health Impact Assessment and the Risk Assessment. Measurements show that PAHs, aldehydes and diossin and furans are almost always below the detection limit, in both biogas and natural gas exhausts. The carcinogenic risk analysis of PAHs for the two fuels established their substantial equivalence. The analysis of equivalent toxicity of dioxins and furans reveals that biogas is, on average, 10 times more toxic than natural gas. Among regulated emissions, NOx in the biogas engines exhausts are three times higher than those of natural gas. They are the main contributors to human health damage, with approximately 90% of the total. SOx ranks second and accounts for about 6% of the total damage. Therefore, (i) the contribution to human health damage of unregulated emissions is limited compared to the damage from unregulated emissions, (ii) the damage per unit of electricity of biogas engines exhausts is about three times higher than that of natural gas and it is directly linked to NOx, (iii) obtaining a good estimation of the human health damage from both biogas and natural gas engines emissions is enough of a reason to consider NOx and SOx
Regulated emissions of biogas engines—on site experimental measurements and damage assessment on human health
Full text linkDespite biogas renewability, it is mandatory to experimentally assess its combustion products in order to measure their pollutants content. To this purpose, the Authors selected six in-operation biogas plants fed by different substrates and perform an on-site experimental campaign for measuring both biogas and engines exhausts composition. Firstly, biogas measured compositions are compared among them and with data available in literature. Then, biogas engines’ exhaust compositions are compared among them, with data available in literature and with measurements obtained from an engine characterised by the same design power but fuelled with natural gas. Finally, the Health Impact Assessment analysis is used to estimate the damage on human health caused by both biogas and natural gas engines emissions. Results show that biogas causes a damage on human health three times higher than the natural gas one. But, this approach does not consider biogas renewability. So, to include this important aspect, also an analysis which considers Global Warming categories is carried out. Results highlight that natural gas is twice harmful than biogas
Costs to reduce the human health toxicity of biogas engine emissions
Full text linkThe anaerobic digestion of biodegradable substrates and waste is a well-known process that can be used worldwide to produce a renewable fuel called biogas. At the time of writing, the most widespread way of using biogas is its direct usage in combined heat and power internal combustion engines (CHP-ICEs) to generate electricity and heat. However, the combustion process generates emissions, which in turn have an impact on human health. Therefore, there is a need to: (i) measure the ICE emissions (both regulated and unregulated), (ii) compute the impact on human health, (iii) identify the substances with the highest impact and (iv) calculate the avoided damage to human health per Euro of investment in technology able to abate the specific type of pollutant. To this end, the authors conducted an experimental campaign and selected as a test case a 999 kWel biogas internal combustion engine. Then, the collected data, which included both regulated and unregulated emissions, were used to calculate the harmfulness to human health and identify the more impactful compounds. Thus, combining the results of the impact analysis on human health and the outcomes of a market analysis, the avoided damage to human health per Euro of investment in an abatement technology was computed. In this manner, a single parameter, expressed in DALY e-1, provided clear information on the costs to reduce each disability-adjusted life year (DALY). The impact analysis on human health, which was performed using the Health Impact Assessment, showed that NOx was the main contributor to damage to human health (approximately 91% of the total), followed by SOx (6.5%), volatile organic compounds (1.4%) and CO (0.7%). Starting from these outcomes, the performed investigation showed that the technology that guarantees the maximum damage reduction per unit of cost is the denitrification system or the oxidizing converter, depending on whether the considered plant is already in-operation or newly built. This is an unexpected conclusion considering that the most impacting emission is the NOx
Applicazione della simulazione termoeconomica allo studio dei parametri di progetto della sezione a vapore di un impianto combinato. Parte B: Influenza della valorizzazione dell’energia elettrica sul costo di produzionedell’ energia termica
No full textPossible Ways of Extending the Biogas Plants Lifespan after the Feed-In Tariff Expiration
Full text linkEnergy production from biogas can play a pivotal role in many European countries, and specifically in Italy, for three main reasons: (i) fossil fuels are scarce, (ii) imports cover large shares of internal demand, and (iii) electricity and heat production from biogas is already a consolidated business. Nonetheless, in Italy, current legislation and incentive policies on electricity generation from biogas are causing a stagnation of the entire sector, which may lead to the shutting down of many in-operation plants in the years 2027–2028 and the consequent loss of 573 MWel over a total of 1400 MWel. This work aims to investigate the potential of revamping biogas power plants in prolonging operation until the end of the plants’ useful life, regardless of the implementation of a new government’s incentive schemes. Based on the time-series analysis of electricity prices in Italy and a case study representative of the vast set of in-operation power plants, our findings show that 700 plants will likely shut down between 2027 and 2028 unless the government adequately rewards electricity produced and fed into the grid via incentive schemes. In detail, our results show that the investment to revamp the plant exhibits a highly negative Net Present Value
IMMUNOTOXICITY OF ZINC PYRITHIONE IN TUNICATES
No full textAfter TBT ban by many world's countries due to its severe impact to coastal ecosystems mainly related to immunosuppressive effects on both invertebrates and vertebrates, alternative biocides have been massively introduced in formulations of antifouling paints. Zinc pyrithione (ZnP) is one of these new generation biocides, previously used in dermatology for its antidundruff and antimycotic action. However, up to now, no data are available concerning its potential target organisms, long-term toxic effects on biocenoses, mechanisms of action, bioaccumulation and environmental fate.
Our interest in the study of ascidian defence reactions led us to investigate the effects of ZnP on cultured phagocytes of the colonial ascidian Botryllus schlosseri, already used in immunotoxicity studies of TBT. We set up short-term haemocyte cultures (60 min at 25 °C) exposed to various concentrations (0.1 to 10 μM) of ZnP (LC50 = 82.5 μM). The amoebocytic index, i.e., the percentage of cells with amoeboid shape, and the phagocytic index, i.e., the percentage of haemocytes containing phagocytised yeast cells, were significantly (p<0.05) reduced after exposition to 0.1 and 0.5 μM ZnP, respectively. These effects were dose- and time-dependent, and irreversible, similarly to those reported for TBT. Detection of microfilaments and microtubules at light fluorescence microscope by means of FITC-phalloidin and anti--tubulin antibody, respectively, revealed thorn-shaped, cytoplasmic prolongations due to cytoskeletal alterations only in the actinic component. Isodynamic mixtures of ZnP and TBT showed an antagonistic interaction on their effects on the amoebocytic index, although no cytoskeletal disassembly was observed, and a significant (p<0.05) detachment of cells from the substrate occurred after incubation at 0.5 μM. Moreover, like TBT, ZnP induced apoptosis which was detected both as chromatin condensation with acridine orange at 0.1 μM and chromatin fragmentation with TUNEL reaction at 0.5 μM. The latter concentration also significantly (p<0.001) affected both oxidative phosphorylation and lysosomal activities through the inhibition of cytochrome-c-oxidase and acid phosphatase activity, respectively. Differently to TBT, no effect was observed on Ca2+ homeostasis, since no decrement in Ca2+-ATPase activity occurred, although a little increase in cytosolic Ca2+ was detected after incubation at the highest concentration. In conclusion, our results demonstrate that ZnP shows a strong toxicity on cultured haemocytes at very low concentrations and interferes with fundamental cell activities. Therefore, this substituent biocide results as much toxic as TBT and, since many of its mechanisms of action are unknown, it represents a potential risk for the environmental health.
This work was supported by grants of Co.Ri.La
On the Use of the Disability-Adjusted Life Year (DALY) Estimator as a Metric to Optimally Manage ICE Emissions
Full text linkWe propose a new management strategy for engines equipped with automatic transmissions based on the damage to human health caused by emissions. The damage to human health is quantified by the years of life lost in a population due to disability or early death caused by exposure to pollutants. Various engine emissions share a common factor: damage to human health.
Our strategy aims to keep engines running along the line of minimum damage instead of focusing on minimal fuel consumption. We applied the minimum damage strategy to the powertrain of a light vehicle to evaluate its effectiveness. In this work, we discuss this trategy’s effects on continuous variable transmission and seven gears automatic transmission and compare the classic minimum
fuel consumption strategy to the minimum damage strategy. The latter results in a 50% reduction in damage compared with the minimum consumption strategy at the expense of an 8% increase in fuel consumption
EXSO: EXergoeconomic Symbolic Optimization method for Energy Systems I - Description of the method
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