| 1. |
- Bolzonella, David, et al.
(author)
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Recent developments in biohythane production from household food wastes : A review
- 2018
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In: Bioresource Technology. - : Elsevier BV. - 0960-8524. ; 257, s. 311-319
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Journal article (peer-reviewed)abstract
- Biohythane is a hydrogen-methane blend with hydrogen concentration between 10 and 30% v/v. It can be produced from different organic substrates by two sequential anaerobic stages: a dark fermentation step followed by a second an anaerobic digestion step, for hydrogen and methane production, respectively. The advantages of this blend compared to either hydrogen or methane, as separate biofuels, are first presented in this work. The two-stage anaerobic process and the main operative parameters are then discussed. Attention is focused on the production of biohythane from household food wastes, one of the most abundant organic substrate available for anaerobic digestion: the main milestones and the future trends are exposed. In particular, the possibility to co-digest food wastes and sewage sludge to improve the process yield is discussed. Finally, the paper illustrates the developments of biohythane application in the automotive sector as well as its reduced environmental burden.
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| 2. |
- Fougeres, Chloe, et al.
(author)
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Search for Na-22 in novae supported by a novel method for measuring femtosecond nuclear lifetimes
- 2023
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In: Nature Communications. - : Springer Nature. - 2041-1723. ; 14:1
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Journal article (peer-reviewed)abstract
- Classical novae are thermonuclear explosions in stellar binary systems, and important sources of Al-26 and Na-22. While ? rays from the decay of the former radioisotope have been observed throughout the Galaxy, Na-22 remains untraceable. Its half-life (2.6 yr) would allow the observation of its 1.275 MeV ?-ray line from a cosmic source. However, the prediction of such an observation requires good knowledge of its nucleosynthesis. The Na-22(p, ?)Mg-23 reaction remains the only source of large uncertainty about the amount of Na-22 ejected. Its rate is dominated by a single resonance on the short-lived state at 7785.0(7) keV in Mg-23. Here, we propose a combined analysis of particle-particle correlations and velocity-difference profiles to measure femtosecond nuclear lifetimes. The application of this method to the study of the Mg-23 states, places strong limits on the amount of Na-22 produced in novae and constrains its detectability with future space-borne observatories. The authors report a particle-particle correlation and velocity-difference profile method to measure nuclear lifetime. The results obtained for excited states of 23Mg are used to constrain the production of 22Na in the astrophysical novae explosions.
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| 3. |
- Micolucci, Federico, et al.
(author)
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Pilot-scale multi-purposes approach for volatile fatty acid production, hydrogen and methane from an automatic controlled anaerobic process
- 2020
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In: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 277
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Journal article (peer-reviewed)abstract
- A combined two-levels control method has been developed and tested on a long term operation of a two-phases pilot-scale anaerobic process for the concurrent production of volatile fatty acids, hydrogen and methane. The latter was designed for the treatment of food waste of urban origin (namely, the organic fraction of municipal solid waste). The optimized control method was set on the base of the inputs of three online probes: a pH-meter in the fermentation reactor, a pH-meter and a conductivity probe in the digestion reactor. The first control level managed the pH in the fermentation reactor while the second control level managed the ammonia concentration in the digestion reactor. This combination established the volume of the digestate to be recycled from the digestion to the fermentation reactor, optimizing the yield of volatile fatty acid (0.31–0.32 kg CODVFA/kg CODfed) and the specific hydrogen production (SHP; 0.070–0.074 m3 H2/kg TVSfed) in the fermentation reactor and the specific methane production (SMP; 0.48–0.55 m3 CH4/kg TVSfed) in the digestion reactor. A new process configuration was also proposed and applied over the course of the long operation period. This configuration allowed to remove part of the volatile fatty acid-rich liquid stream from the fermenter effluent, maintaining the corresponding solid-rich effluent in the whole system (as feed for the digestion reactor) by using a solid/liquid separation unit. In this way, the concentration of volatile fatty acids in the digester was kept at a low level, even with high loading rates, so maintaining a satisfying efficiency of methane production and utilizing the excess volatile fatty acids (out of the system) as building blocks for other purposes. The optimized two-levels control method for the anaerobic treatment of food waste provides new perspectives for the valorisation of such waste stream; the production of building blocks namely volatile fatty acids supports new innovative bio-refinery platforms for the production of bio-products.
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| 4. |
- Valentino, Francesco, et al.
(author)
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Organic Fraction of Municipal Solid Waste Recovery by Conversion into Added-Value Polyhydroxyalkanoates and Biogas
- 2018
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In: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 6:12, s. 16375-16385
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Journal article (peer-reviewed)abstract
- The integrated-multistage process proposed herein is a practical example of a biorefinery platform in which the organic fraction of municipal solid waste (OFMSW) is used as a valued source for polyhydroxyalkanoates (PHA) and biogas production. Technical and economical feasibilities of this approach have been demonstrated at pilot-scale, providing a possible upgrade to traditional biowaste management practices, presently based on anaerobic digestion (AD). A pH-controlled OFMSW fermentation stage produced a liquid VFA-rich stream with a high VFA/CODSOL ratio (0.90 COD/COD) that was easily used in the following aerobic stages for biomass and PHA production. The solid fraction was valorized into biogas through AD, obtaining energy and minimizing secondary flux waste generation. The reliable biomass enrichment was demonstrated by a stable feast-famine regime and supported by microbial community analysis. The selected consortium accumulated PHA up to 55% wt. Compared to the traditional AD process in an urban scenario of 900000 AE, the integrated approach for OFMSW valorization is preferable, and it is characterized by an electrical energy production of 85.7 MWh/d and 1.976 t/d as PHA productivity. The proposed process was also evaluated as economically sustainable if the PHA is marketed from 0.90 €/kg as the minimum threshold to a higher market price.
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