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Dive into the research topics where Antonio Di Molfetta is active.

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Featured researches published by Antonio Di Molfetta.


Journal of Environmental Quality | 2009

Hydrogeochemical and Biological Processes Affecting the Long-term Performance of an Iron-Based Permeable Reactive Barrier

Valerio Zolla; Francesca Stefania Freyria; Rajandrea Sethi; Antonio Di Molfetta

Despite the wide diffusion of zero-valent iron (Fe(0)) permeable reactive barriers (PRBs), there is still a great uncertainty about their longevity and long-term performance. The aim of this study is to investigate the biological and the hydrogeochemical processes that take place at a Fe(0) installation located in Avigliana, Italy, and to derive some general considerations about long-term performance of PRBs.The examined PRB was installed in November 2004 to remediate a chlorinated solvents plume (mainly trichloroethene and 1,2-dichloroethene). The investigation was performed during the third year of operation and included: (1) groundwater sampling and analysis for chlorinated solvents, dissolved CH(4), dissolved H(2) and major inorganic constituents; (2) Fe(0) core sampling and analysis by SEM-EDS, XRD, and FTIR spectroscopy for the organic fraction; (3) in situ permeability tests and flow field monitoring by water level measurements.The study revealed that iron passivation is negligible, as the PRB is still able to effectively treat the contaminants and to reduce their concentrations below target values. Precipitation of several inorganic compounds inside the PRB was evidenced by SEM-EDS and XRD analysis conducted on iron samples. Groundwater sampling evidenced heavy sulfate depletion and the highest reported CH(4) concentration (>5,000 microg/L) at zero-valent iron PRB sites. These are due to the intense microbial activity of sulfate-reducers and methanogens, whose proliferation was most likely stimulated by the use of a biopolymer (i.e. guar gum) as shoring fluid during the excavation of the barrier. Slug tests within the barrier evidenced an apparent hydraulic conductivity two orders of magnitude lower than the predicted value. This occurrence can be ascribed to biofouling and/or accumulation of CH(4)(g) inside the iron filings.This experience suggests that when biopolymer shoring is planned to be used, long-term column tests should be performed beforehand with initial bacterial inoculation and organic substrate dosing, in order to predict the effects of bacterial overgrowth and gas generation. During construction particular care should be taken in order to minimize the amount of used biopolymer so that complete breakdown can be achieved.


Water Resources Research | 2008

An automatic, stagnation point based algorithm for the delineation of Wellhead Protection Areas

Tiziana Anna Elisabetta Tosco; Rajandrea Sethi; Antonio Di Molfetta

[1]xa0Time-related capture areas are usually delineated using the backward particle tracking method, releasing circles of equally spaced particles around each well. In this way, an accurate delineation often requires both a very high number of particles and a manual capture zone encirclement. The aim of this work was to propose an Automatic Protection Area (APA) delineation algorithm, which can be coupled with any model of flow and particle tracking. The computational time is here reduced, thanks to the use of a limited number of nonequally spaced particles. The particle starting positions are determined coupling forward particle tracking from the stagnation point, and backward particle tracking from the pumping well. The pathlines are postprocessed for a completely automatic delineation of closed perimeters of time-related capture zones. The APA algorithm was tested for a two-dimensional geometry, in homogeneous and nonhomogeneous aquifers, steady state flow conditions, single and multiple wells. Results show that the APA algorithm is robust and able to automatically and accurately reconstruct protection areas with a very small number of particles, also in complex scenarios.Time-related capture areas are usually delineated using the backward particle tracking method, releasing circles of equally spaced particles around each well. In this way, an accurate delineation often requires both a very high number of particles and a manual capture zone encirclement. The aim of this work was to propose an Automatic Protection Area (APA) delineation algorithm, which can be coupled with any model of flow and particle tracking. The computational time is here reduced, thanks to the use of a limited number of nonequally spaced particles. The particle starting positions are determined coupling forward particle tracking from the stagnation point, and backward particle tracking from the pumping well. The pathlines are postprocessed for a completely automatic delineation of closed perimeters of time-related capture zones. The APA algorithm was tested for a two-dimensional geometry, in homogeneous and nonhomogeneous aquifers, steady state flow conditions, single and multiple wells. Results show that the APA algorithm is robust and able to automatically and accurately reconstruct protection areas with a very small number of particles, also in complex scenarios


Environmental Earth Sciences | 2015

Groundwater monitoring at a building site of the tidal flood protection system “MOSE” in the Lagoon of Venice, Italy

Alessandro Casasso; Antonio Di Molfetta; Rajandrea Sethi

To protect Venice against tidal flooding, the MOSE system (Experimental Electro-mechanic Module) has been under construction since 2003. This safeguarding system is composed of four batteries of mobile barriers at the Lagoon’s inlets (Lido, Malamocco, Chioggia), which will be lifted before the occurrence of exceptional high tides (>1.10xa0m above the mean sea level), isolating the Venetian Lagoon from the sea. The end of the construction work is foreseen by 2016. In this paper, the results of the groundwater monitoring at the building site of Punta Sabbioni at the Lido inlet are described. A large dewatered basin (tura), formerly occupied by the sea and close to the shoreline, was used for the precasting of the mobile barriers, and the impact of groundwater control was therefore monitored in the phreatic and shallow confined aquifers. Although a slurry wall barrier was excavated to isolate the tura, a drawdown cone in the confined aquifer was observed, extending to 1xa0km from the construction site. In contrast, the phreatic aquifer was only influenced by tides, rainfall and evapotranspiration, and the slurry wall of the tura had a positive effect of decreasing the groundwater salinity by limiting the seawater intrusion, as confirmed by the electrical conductivity profiles measured inside the piezometers. The monitoring activity was successful in assessing the impacts of the construction work on the aquifer system and in distinguishing them from the effects of natural driving forces.


Archive | 2012

Delimitazione delle aree di salvaguardia dei pozzi ad uso potabile

Antonio Di Molfetta; Rajandrea Sethi

Uno dei principali strumenti adottati per la tutela delle acque destinate al consumo umano e rappresentato dalla delimitazione di aree di salvaguardia, da realizzarsi in prossimita delle opere di captazione. La definizione delle aree di salvaguardia (protezione statica), con l’imposizione dei vincoli che limitino l’utilizzo del territorio, non risolve completamente il problema della protezione delle opere di captazione idropotabile, ma si limita ad escludere la possibilita che un processo di inquinamento si inneschi all’interno delle aree di rispetto cosai definite. La garanzia di una protezione delle opere di captazione idropotabile nei riguardi di processi di inquinamento provenienti dall’esterno delle fasce di salvaguardia richiederebbe anche la creazione di una rete di monitoraggio disposta lungo il perimetro delle aree di rispetto sulla quale programmare un periodico controllo della qualita della falda interessata dalle opere di captazione (protezione dinamica).


Archive | 2012

Capacità produttiva ed efficienza idraulica di un pozzo

Antonio Di Molfetta; Rajandrea Sethi

Tutte le soluzioni analitiche dell’equazione di diffusivita, analizzate nel Capitolo 4 e utilizzate nell’interpretazione delle prove di falda, sono equazioni di flusso nel mezzo poroso che prescindono dall’esistenza di un’opera di captazione e dalle sue caratteristiche costruttive. Le prove di falda non possono, conseguentemente, essere utilizzate per valutare le caratteristiche produttive e di efficienza idraulica di un’opera di captazione, obiettivo, questo, che puo essere raggiunto mediante le prove di pozzo. Tali prove consistono nella determinazione sperimentale della relazione numerica che lega la portata erogata da un pozzo alla corrispondente perdita di carico, misurata dal valore stabilizzato dell’abbassamento di livello idrico rispetto alla situazione indisturbata.


Archive | 2012

L’applicazione della legge di Darcy

Antonio Di Molfetta; Rajandrea Sethi

Qualunque studio sulle risorse idriche sotterranee presuppone la conoscenza delle modalita con cui l’acqua si muove nel sottosuolo e cio puo essere ottenuto ricostruendo il campo di moto della falda, vale a dire la distribuzione delle linee di flusso e delle linee a potenziale costante.


Archive | 2012

I contaminanti presenti nelle acque sotterranee

Antonio Di Molfetta; Rajandrea Sethi

Nonostante la consapevolezza che l’acqua rappresenta l’elemento piu importante per la vita, l’uomo ha dedicato scarsa attenzione ad evitare che lo sviluppo produttivo in campo agricolo ed industriale si accompagnasse a fenomeni di contaminazione delle risorse idriche sotterranee che, talora, per estensione e gravita dei fenomeni, hanno avuto pesanti conseguenze sulla salute della popolazione esposta.


Archive | 2012

Caratterizzazione della contaminazione

Antonio Di Molfetta; Rajandrea Sethi

Nel presente capitolo viene fornito un contributo metodologico per la caratterizzazione della contaminazione nelle differenti matrici presenti nel sottosuolo, distinguendo tra mezzo non saturo, comprendente terreno, gas interstiziale ed acqua interstiziale e mezzo saturo, comprendente le acque di falda.


Archive | 2012

Fondamenti teorici dell’equazione differenziale del trasporto di massa

Antonio Di Molfetta; Rajandrea Sethi

Nel capitolo precedente sono stati descritti singolarmente i processi idrologici, chimico-fisici e biologici che intervengono nella propagazione dei contaminanti nelle acque di falda. Il trasporto di soluti e frutto dell’azione concomitante di questi processi. Il risultato e un fenomeno estremamente complesso, governato dalle continue interazioni che hanno luogo nel sistema acquifero, fra soluto e acqua, fra soluto e matrice solida e fra soluti diversi.


Archive | 2012

Propagazione delle sostanze non miscibili

Antonio Di Molfetta; Rajandrea Sethi

Nei capitoli precedenti sono state prese in esame le soluzioni analitiche che consentono di studiare la propagazione nelle acque sotterranee di contaminanti miscibili con l’acqua di falda, sia di tipo conservativo sia di tipo reattivo.

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