1,721,005 research outputs found
Integrated Water Cycle Sustainability: Water Reuse in Circular Economy (sonozone technology evaluation)
No full textThe work that is presented aims to be a preliminary study on the applicability and potentialities of a low-frequency ultrasonic treatment combined with an ozone disinfection on a primary effluent from an urban wastewater treatment plant for an agricultural reuse (fertigation). The preservation of the nutrients contained in the original wastewater may contribute to the circular economy perspective, reducing the production costs for mineral fertilizers and the freshwater withdrawals. The limited scientific experience towards the hybrid ultrasonic and ozone process, called sonozone, requires an accurate laboratory experimental campaign, focused on the assessment of the regulated physico-chemical and biological compounds, that have to be controlled and maintained below the legislative limits. The importance of the wastewater recovery is nowadays increasing due to the climate change and the population growth. The suitable application of the reclaimed wastewater for fertigation practices could help the process to move towards the integrated water cycle closing, following the circular economy perspective. The primary effluent was appositively selected for the reuse.
The work started with a laboratory-scale calibration of the instruments (ultrasonic probe and ozone generator) separately. An initial semi-continuous ultrasonic process and a discontinuous ozonation were performed. A precise characterization of the primary effluent wastewater was needed before the experiments. Then, the combination of processes in a semi-discontinuous setup allowed to test the coupled effect of the sequential ultrasonic pretreatment and ozonation. The hybrid process’ high removal efficiency was matched by an outstanding retention of nutrients (total nitrogen and total phosphate) highlighting the potential for the primary effluent reuse, with possible significant saving of chemical fertilizers.
The wastewater’ sonozone recovery could save a meaningful amount of nutrients. However, being a well-known energy-consumer processes, it has to be assessed on the field based on the removal capacity. An economic assessment was given for the hybrid technology and compared to other classic secondary and tertiary treatments. Towards a safe microbial recovery, an in-depth analysis on microorganisms was presented. Being only few the mandatory pathogens required in the legislation, additional microorganisms will be tested with the ultrasonic and ozone processes alone and combined. The kinetic modelling and logarithmic abatement of four microbial species, namely Pseudomonas spp., E. coli, Enterococcus spp. and S. Enteritidis, was performed. Moreover, an ecotoxicological in-silico evaluation indicated the sonozone removal capacity towards several hazardous and persistent chemicals, addressing the eco-toxic concentration in different environments, their persistence and solubility in water.
The pilot scale laboratory tests should be intended as the transition from a semi-continuous laboratory scale to a bigger-scale plant running continuously, as a further step for the evaluation of the proposed agricultural reuse.
The circular economy concept is strongly related to the possibilities of the conventionally removed compound to be recovered and reused through the fertigation concept. In order to support the laboratory tests, a meaningful case study was analyzed. Two different scenarios were shown for the extent of expressing a tangible recover of water and nutrients.
The overall study outcomes showed remarkable opportunities for the primary effluent reuse for agricultural purposes in a circular economy perspective, despite energy costs may still hinder the full-scale applicability of this technology. Moreover, the sonozone application in rural areas, not reached by a suitable sewage and depuration system, may result highly recommended for the prospective of direct effluent reuse, especially when coupled with an electricity generator plant (e.g. photovoltaic panels).The work that is presented aims to be a preliminary study on the applicability and potentialities of a low-frequency ultrasonic treatment combined with an ozone disinfection on a primary effluent from an urban wastewater treatment plant for an agricultural reuse (fertigation). The preservation of the nutrients contained in the original wastewater may contribute to the circular economy perspective, reducing the production costs for mineral fertilizers and the freshwater withdrawals. The limited scientific experience towards the hybrid ultrasonic and ozone process, called sonozone, requires an accurate laboratory experimental campaign, focused on the assessment of the regulated physico-chemical and biological compounds, that have to be controlled and maintained below the legislative limits. The importance of the wastewater recovery is nowadays increasing due to the climate change and the population growth. The suitable application of the reclaimed wastewater for fertigation practices could help the process to move towards the integrated water cycle closing, following the circular economy perspective. The primary effluent was appositively selected for the reuse.
The work started with a laboratory-scale calibration of the instruments (ultrasonic probe and ozone generator) separately. An initial semi-continuous ultrasonic process and a discontinuous ozonation were performed. A precise characterization of the primary effluent wastewater was needed before the experiments. Then, the combination of processes in a semi-discontinuous setup allowed to test the coupled effect of the sequential ultrasonic pretreatment and ozonation. The hybrid process’ high removal efficiency was matched by an outstanding retention of nutrients (total nitrogen and total phosphate) highlighting the potential for the primary effluent reuse, with possible significant saving of chemical fertilizers.
The wastewater’ sonozone recovery could save a meaningful amount of nutrients. However, being a well-known energy-consumer processes, it has to be assessed on the field based on the removal capacity. An economic assessment was given for the hybrid technology and compared to other classic secondary and tertiary treatments. Towards a safe microbial recovery, an in-depth analysis on microorganisms was presented. Being only few the mandatory pathogens required in the legislation, additional microorganisms will be tested with the ultrasonic and ozone processes alone and combined. The kinetic modelling and logarithmic abatement of four microbial species, namely Pseudomonas spp., E. coli, Enterococcus spp. and S. Enteritidis, was performed. Moreover, an ecotoxicological in-silico evaluation indicated the sonozone removal capacity towards several hazardous and persistent chemicals, addressing the eco-toxic concentration in different environments, their persistence and solubility in water.
The pilot scale laboratory tests should be intended as the transition from a semi-continuous laboratory scale to a bigger-scale plant running continuously, as a further step for the evaluation of the proposed agricultural reuse.
The circular economy concept is strongly related to the possibilities of the conventionally removed compound to be recovered and reused through the fertigation concept. In order to support the laboratory tests, a meaningful case study was analyzed. Two different scenarios were shown for the extent of expressing a tangible recover of water and nutrients.
The overall study outcomes showed remarkable opportunities for the primary effluent reuse for agricultural purposes in a circular economy perspective, despite energy costs may still hinder the full-scale applicability of this technology. Moreover, the sonozone application in rural areas, not reached by a suitable sewage and depuration system, may result highly recommended for the prospective of direct effluent reuse, especially when coupled with an electricity generator plant (e.g. photovoltaic panels)
Aspetti geoeconomici del turismo montano in Italia. Analisi dei flussi, competitori internazionali, criticità territoriali.
No full textIl turismo italiano presenta fondamentali economici in un quadro infrastrutturale ancora competitivo in riferimento alla concorrenza degli altri paesi alpini. Tuttavia la fragilità dell'ecosistema e la peculiarità del quadro infrastrutturale rappresentano fayyori di criticità nell'utilizzo del territorio.Tourism in Italy shows consistent economic basiscs and it relies on competitive facilities when compared to other Alp's countries offer. Nevertheless, a fragile ecosystem and the distinguishing features of the facilities themselves are crucial to the environment utilization
Un'analisi geoeconomica dell'accessibilità turistica
No full textEsiste un complesso rapporto tra la qualità del servizio turistico e la reale potenzialità della fruizione. Questo condiziona fortemente il rapporto tra territorio e sviluppo turistico.The articles offers some insights and analysis on the relation between tourism development and transport accessibility in Ital
L’edilizia popolare e sociale, tra approccio sistemico e teoria della complessità. Urgenze e insidie progettuali
No full textIl lavoro indaga teoria ed esperienza recente del social housing, una realtà invero assai complessa, sfaccettata e cangiante, specialmente nelle implementazioni degli ultimi decenni nei Paesi Occidentali o a industrializzazione matura. L'analisi, dopo aver ripercorso le impostazioni concettuali prevalenti ed evidenziato gli elementi di maggiore criticità o problematicità dei programmi di edilizia sociale e/o popolare in Europa, sottolinea la crescente conflittualità della impostazione e realizzazione di nuove edificazioni sociali/popolari per via tanto di criticità tanto sotto il profilo economico-finanziario, quanto ancora nell'accettazione sociale e nella desiderabilità degli effetti a più lungo termine (tutto ciò riconduce quindi a un'idea di sostenibilità a 360° ovvero anche extra-economica)
IL SISTEMA DI OFFERTA: IL TURISMO SPORTIVO
No full textI grandi eventi sportivi possono rappresentare un potente volano per lo sviluppo economico del paese o della località ospitante l'evento. Tutavia le condizioni perchè tutto questo avveng sono numerose e complesse.Major sporting events can be a powerful driving force for the economic development of the country or the city hosting the event. Tutavia conditions avveng why all this are many and complex
Accessibilità, competitività e sviluppo turistico
No full textEsiste una correlazione significativa tra sviluppo ed accessibilità turistica. In particolare questa ultima puiò essere espressa sotto numerose forme con conseguenti diverse ricadute sul sistema turistico.The article offers an evaluation on the correlation between tourism development and transport accessibility in Italy
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
Corrigendum to “100% renewable wastewater treatment plants: Techno-economic assessment using a modelling and optimization approach” [Energy Convers. Manage. 239 (2021) 114214]
No full textRespirometry tests in wastewater treatment: Why and how? A critical review
Full text linkRespirometry tests are a widely employed method in the wastewater treatment field to characterize wastewater streams, assess toxic/inhibitory effects to the biomass, calibrate mathematical models. Respirometry can allow to fractionation the chemical oxygen demand (COD) in biodegradable and inert fractions, but also provide information related to biomass kinetics and stoichiometry through standardized laboratory techniques. Considering the increasing number of emerging contaminants detected in wastewater effluents, such as pharmaceuticals, personal care products and pesticides, respirometry can be a useful tool to promptly assess any toxic or inhibitory effect in wastewater treatment plant (WWTP) operations. Beside conventional activated sludge, in recent years respirometric methods have been applied to innovative fields, such as moving-bed bio-reactors (MBBRs), fungi and microalgae, exploiting natural remediation methods. In particular, respirometry application to microalgae, through the so-called photo-respirometry, has been investigated in the latest years in the treatment of high-loaded streams, allowing resource recovery in biomass form. In this work, respirometric methods are first introduced from a theoretical basis and then critically discussed by considering the experimental apparatus, the available characterization protocols and the fields of application; the most recent literature findings on respirometry are coupled with authors' experience in the field. A comparison between physicochemical methods and respirometry is made. The future research needed on the topic is finally outlined, including the coupling of respirometry with microbial community analysis, potentially leading to an enhanced process understanding, an extended respirometry utilization to get specific kinetic and stoichiometric parameters for modelling purposes, and a wider respirometry application as a diagnosis tool in WWTP operations
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