Search results for " Ingegneri"
showing 10 items of 809 documents
IL NOCCIOLINO DI OLIVE COME SUBSTRATO ORGANICO PER LA DENITRIFICAZIONE BIOLOGICA DELLE ACQUE DI FALDA
2015
La denitrificazione biologica come trattamento in situ delle falde contaminate ha riscosso grande interesse negli ultimi decenni; coniuga l’efficacia di rimozione ai costi relativamente contenuti se , confrontati con altre metodiche di intervento. La resa di tale tecnologia di trattamento è fortemente condizionata dalla scelta del materiale reattivo che fornisce il carbonio organico necessario a sostenere il processo. Diversi studi hanno evidenziato la possibilità di operare la denitrificazione biologica a partire da substrati di natura legnosa (segatura, corteccia, etc.). In tale ottica, la nota presenta i risultati preliminari ottenuti utilizzando come substrato il nocciolino di olive tri…
Influenza dei polimeri extracellulari sul fouling e sul foaming negli impianti MBR.
2009
L’applicazione sempre più diffusa dei bioreattori a membrana presenta tuttavia ancora alcuni fattori limitanti che ne condizionano l’adozione: infatti sono ancora incerte le previsioni della vita utile e dell’efficienza della barriera filtrante. In particolare, notevole incidenza sul processo ha il fouling, causato principalmente dai fenomeni di sporcamento condizionati prevalentemente dalla composizione della sospensione biologica sottoposta a filtrazione. Nella nota sono riportati i risultati di uno studio sperimentale che ha avuto per oggetto l’analisi dell’influenza di alcuni parametri specifici che, oltre a descrivere la qualità del fango attivo dei sistemi MBR, influenzano il processo…
The fouling phenomenon in membrane bioreactors: assessment of different strategies for energy saving
2012
Membrane fouling represents one of the major limiting issue for membrane bioreactor (MBR) in the wastewater treatment field. Membrane fouling and high aeration requirement (for inducing shear stress to limit fouling) in MBR systems make the operation of such systems economically demanding due to high energetic costs. Despite several studies on MBR fouling have been performed a comprehensive knowledge on how to reduce membrane fouling and consequently energy saving is still lacking and controversial. The aim of this study is to gain insights on the optimization of the operating conditions in an MBR system. In particular, the influence of the aeration intensity and the durations of filtration…
Uncertainty propagation throughout an integrated water-quality model
2010
In integrated urban drainage water quality models, due to the fact that integrated approaches are basically a cascade of sub-models (simulating sewer system, wastewater treatment plant and receiving water body), uncertainty produced in one sub-model propagates to the following ones depending on the model structure, the estimation of parameters and the availability and uncertainty of measurements in the different parts of the system. Uncertainty basically propagates throughout a chain of models in which simulation output from upstream models is transferred to the downstream ones as input. The overall uncertainty can differ from the simple sum of uncertainties generated in each sub-model, dep…
Biological nutrient removal in a UCT-MBR pilot
2010
In the last years, there has been an increasing awareness about the environment pollution protection. As a consequence, the Environmental Regulation has increased the emission limits imposing, for instance, lower concentrations at the wastewater treatment plant (WWTP) outlets. As a consequence of this fact, several WWTPs are not able to respect the emission limits and need to be upgraded. In view of such needs new technology are emerging and new WWTP solution schemes are being realized. With respects to the nutrient removal enhancing, a possible solution can be the UCT-MBR which couples the University of Cape Town scheme with a Membrane Bioreactor. In the light of such considerations, the s…
The management of sewage sludge: technologies, critical issue and perspectives
2022
The management of sludge produced by urban wastewater treatment plants has long been a problem for plant managers. This is due both to the growing costs for their disposal, and to the possible consequences that incorrect management may have on the performance of the wastewater treatment plant and on the environment. Further difficulties arose following the evolution of the European and national legislations, which regulates the management of sludge and its possible agronomic uses that introduced further checks and restrictions for this use. Several studies have been underway since last decades to reduce the extent of the problem. These focus on alternative objectives being aimed on the one …
Trattamento di reflui industriali con sistemi biologici a biomassa aerobica granulare: analisi delle performance di processo e della stabilità del fa…
Greenhouse Gas Emissions from Membrane Bioreactors
2017
Nowadays, it is widely accepted that wastewater treatment plants (WWTPs) are significant sources of greenhouse gas (GHG) emission, contributing to the anthropogenic sources. Among the GHG emitted from WWTPs, nitrous oxide (N2O) has been identified of having the major interest/concern, since its high global warming potential (GWP), is 298 times higher than that of CO2 and also to its capability to react with stratospheric ozone causing the layer depletion. Up to now, most of the experimental investigations have been carried out on conventional activated sludge (CAS) processes. The knowledge of N2O emission from advanced technologies such membrane bioreactors (MBRs) is still very limited. The…