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Two-phase thermophilic anaerobic digestion process for biohythane production treating biowaste: preliminary results.
Full text linkThis paper deals with the optimisation of a two-phase anaerobic process treating biowaste for hydrogen and methane production. Nor physical neither chemical pre treatments were used to optimise the process. The work was carried out at pilot scale, using two CSTRs (200 l and 380 l working volume respectively) both maintained at thermophilic temperature (55°C) and fed semi-continuously with biowaste. The experiment was divided in three periods; during the first two periods the organic loading rate was maintained at 20 kgTVS/m3d and the hydraulic retention time was changed from 6.6 to 3.3 days, while in the last period the digestate of the second reactor was recirculated to the first reactor in order to buffer the system and control pH at levels around 5. The HRT was maintained at 3.3 days and the OLR was decreased at 16.5 kgTVS/m3d. The best yield was obtained in the last period where a specific hydrogen production of 50.9 l/kgVSfed was reached, with a H2 content in biogas from the first reactor of 36%. The methanogenic stage after the hydrogen conversion reached a specific biogas production of 0.62 m3/kgVSfed and an overall organic removal above 70%, without any stability problem. The overall biogas production was some 1.5 m3 per day with a gas composition of 10% H2 and 50% CH4
Nota introduttiva
No full textPrefazione al volume di Bolzonella inerente alle acquisizioni della città lagunare in terrafermai precedenti alla costituzione dello Stato da Terra
Biohydrogen production from food waste in batch and semi-continuous conditions: evaluation of a two-phase approach with digestate recirculation for pH control
Full text linkThe research investigated the production of Biohythane in a two-phase anaerobic digestion process treating food waste as substrate. Preliminary batch assays were carried out at initial organic loadings of 15, 20, 25 and 30 kg TVS m?3, in stirred 1.5-l reactors at 55 °C. The results showed all hydrogen was produced within the first 24 h after feeding and the highest load tested gave the maximum hydrogen production (0.047 m3 H2 kg?1VS, H2 30%). Similar loadings were then tested in a two-phase system. Hydraulic retention times of 3 and 12 days were applied to the first and second reactor respectively. In order to keep the pH at ?5.5, either supernatant or whole digestate from the methanogenic reactor was recirculated to the first phase. Results showed that hydrogen was produced (0.117 Nm3 kg?1 VS, 47.7%) when recirculating whole digestate with an organic loading rate of 20 kg TVS m?3 day?1
Mariangela Bordin, Le ville di Noventa Padovana e il loro dialogo con l'acqua, in Marco Bolzonella (a cura di), Noventa Padovana villa bellissima tra Brenta e Piovego. Storia, arte e territorio, Padova, cleup, 2018, pp. 149-166.
No full textIn questo contributo ci si propone di analizzare le ville di Noventa Padovana soprattutto tenendo come riferimento il loro rapporto con l'acqu
Effect of trace element supplementation on the mesophilic anaerobic digestion of foodwaste in batch trials: the influence of inoculum origin
Full text linkBatch anaerobic trials using a source-separated food waste as a substrate with inoculums of
different origins were carried out under mesophilic conditions. Reactions were operated both with
and without trace element (Co, Mo, Ni, Se, W) supplementation. Supplementation with trace metals
had either neutral or slightly negative effects with inoculums originating from reactors with a high
background level of metals, such as those for the co-digestion of biowaste and waste activated
sludge. For inoculums from reactors treating food waste only, which inherently contain low levels
of trace metals, supplementation with these metals increased methane production. In particular, Mo
concentrations in the range of 3-12 mg per kg dry matter and Se concentrations of 10 mg per kg dry
matter increased methane production to as high as 30-40%. Supplementation with a metal mixture
(Co, Mo, Ni, Se and W) increased the methane production to the range 45-65% for inoculums with
low background concentrations of trace metals. These findings may have an important impact in the
commercial production of methane from food waste
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Application of a membrane biological reactor (MBR) for the removal of nutrients and micropollutants and wastewater reclamation and reuse
No full textL’acqua disponile per uso umano (diretto e non) sul nostro pianeta sta costantemente diminuendo, tanto che, secondo stime dell’ONU, nel 2025 due persone su tre non avranno accesso a risorse idriche utilizzabili. Ciò è imputabile non solo ai ridotti quantitativi disponibili, ma anche al costante peggioramento delle caratteristiche chimico-fisiche e microbiologiche delle riserve idriche. Ne consegue la necessità di introdurre processi avanzati per il trattamento delle acque reflue, in grado di produrre effluenti con qualità elevatissima, idonei tanto allo scarico in zone particolarmente sensibili dal punto di vista ambientale, quanto al diretto riutilizzo per fini industriali e/o agricoli. L’applicazione di processi biotecnologici è orami da tempo un must nel settore del trattamento delle acque reflue.
Nel corso del triennio di dottorato di ricerca si è quindi condotto lo studio approfondito di un processo biotecnologico per il trattamento avanzato di acque reflue reali di origine mista, civile ed industriale in bioreattore a membrana (MBR).The necessity to reclaim wastewater determined the introduction of memebrane bioreacotrs for successfull treatment at very high efficiecny standard
Benefits and Drawbacks of Non-Destructive Assay (NDA) for Nuclear Safeguards – An Overview
Full text linkNuclear safeguards are technical measures used to detect the diversion of nuclear material and technologies from their peaceful use. A key trait of safeguards is represented by measurements, which allow operators and inspectors to verify the nuclear activities and the amount of nuclear material declared by the States. In particular, an important class of measurements are Non-Destructive Assay (NDA) techniques, which allow one to characterize samples while preserving their physical integrity. NDA represents a rapid and effective method for measurements of nuclear materials in a variety of situations (from process lines to finished products, scrap and waste materials), with the possibility to perform on-site measurements, reducing radioactive waste production and offering wide margins for automatization and remote operation. However, there are situations where the use of NDA is not recommended or possible and one has to rely on Destructive Assay (DA) (i.e., techniques which alter the integrity of the item analysed). This happens, for example, in environmental sampling, when dealing with highly diluted nuclear materials, or when the radiation emitted by the sample is weakly penetrating. In conclusion, the integrated use of different NDA and DA techniques is the best possible solution for measurements in the frame of nuclear safeguards
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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