1,721,025 research outputs found
Valutazione della sicurezza e controlli di accettazione del calcestruzzo confezionato con i residui dei termovalorizzatori di RSU a letto fluido
No full textApplicazione delle analisi reologiche alla gestione degli impianti di depurazione a fanghi attivi
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Ceneri da rifiuti solidi - Confezionare calcestruzzo da scorie e sabbie esauste: sicurezza e accettazione
No full textLa gestione dei residui derivanti da inceneritori a letto fluido: confezionamento di calcestruzzo e valutazione della sicurezza
No full textControllo di funzionalità applicato ad un impianto di trattamento di acque reflue domestiche e rifiuti liquidi industriali quali strumento per l’ottimizzazione della gestione
No full textEcotoxicological assessment of waste foundry sands and the application of different classification systems
Full text linkThe application of a battery of bioassays is widely recognized as a useful tool for assessing environmental hazard samples. However, the integration of different toxicity data is a key aspect of this assessment and remains a challenge. The evaluation of industrial waste leachates did not initially undergo any of the proposed integration procedures. This research addressed this knowledge gap. Twenty-five samples of waste foundry sands were subjected to a leaching test (UNI EN 12457-2) to evaluate waste recovery and landfill disposal. The leachates were evaluated using a battery of standardized toxicity bioassays composed of Aliivibrio fischeri (EN ISO 11348-3), Daphnia magna (UNI EN ISO 6341), and Pseudokirchneriella subcapitata (UNI EN ISO 8692), both undiluted and diluted. Daphnia magna and P. subcapitata were the most affected organisms, with significant effects caused by 68% and 64% of undiluted samples, respectively. The dilution of samples facilitates the calculation of EC50 values, which ranged from greater than the highest concentration tested to 2.5 g/L for P. subcapitata. The data on single-organism toxicity were integrated using three methods: the Toxicity Classification System, the toxicity test battery integrated index, and the EcoScore system. The three classifications were strongly similar. According to all applied systems, three samples were clearly nontoxic (from iron casting plants) and two were highly toxic (from steel casting plants). Moreover, the similar ranking between undiluted and diluted leachates suggests the possibility of using only undiluted leachates for a more cost-effective and time-efficient screening of waste materials. The findings of this study highlight the usefulness of integrating ecotoxicological waste assessment
Verifiche di funzionalità applicate ad un impianto di depurazione con forte prevalenza di rifiuti liquidi industriali rispetto ai liquami domestici: il caso di Mortara (PV)
No full textWhy use a thermophilic aerobic membrane reactor for the treatment of industrial wastewater/liquid waste?
No full textThis paper describes the advantages of thermophilic aerobic membrane reactor (TAMR) for the treatment of high strength wastewaters. The results were obtained from the monitoring of an industrial and a pilot scale plant. The average chemical oxygen demand (COD) removal yield was equal to 78% with an organic loading rate (OLR) up to 8-10 kgCOD m(-3) d(-1) despite significant scattering of the influent wastewater composition. Total phosphorus (TP) was removed with a rate of 90%, the most important removal mechanism being chemical precipitation (as hydroxyapatite, especially), which is improved by the continuous aeration that promotes phosphorus crystallization. Moreover, surfactants were removed with efficiency between 93% and 97%. Finally, the experimental work showed that thermophilic processes (TPPs) are complementary with respect to mesophilic treatments
CFD-aided modelling for hydrodynamic analysis of biological reactor
No full textThe performance testing of treatment plants is of great concern in the field of environmental engineering, especially regarding the management of wastewater plants devoted to treatment and reuse. The efficiency of the treatment process is strictly related to both biological kinetics and hydrodynamics, influencing each other. In fact, the actual hydrodynamic behaviour of a biological reactor can deviate significantly from the design hypotheses, leading to hydraulic defects such as formation of dead volume and bypass. These problems exert a strong influence on the biological process and therefore affect the treatment efficiency of the plant. The Residence Time Distribution (RTD) analysis is commonly adopted for quantifying the type and amount of the functioning deficiencies affecting the process. However, to address the corrective intervention, these deficiencies should be localized by integrating RTD method with Computational Fluid Dynamics (CFD). This paper shows the early studies of a wider research project aiming at developing a standardized method combining RTD and CFD techniques for mitigating or eliminating functioning defects in biological reactors. An application of CFD-aided modelling for assessing hydrodynamic behaviour of an activated sludge (AS) pilot plant is illustrated. The obtained results are compared with experimental results from RTD analysis, showing how the CFD model can help supporting design of new facilities and the optimization or retrofitting of existing facilities for wastewater treatment
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