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Descrizione delle attività di ricerca condotte sul Mar Piccolo di Taranto

Studio di Fattibilità a Bari: questo studio descrive la valutazione geotermica effettuata nel sito di Bari e la proposta tecnico-economica per lo sviluppo di un progetto impiantistico relativo a risorse geotermiche a bassa entalpia per la realizzazione di un impianto di climatizzazione dell'Istituto di Ricerca Sulle Acque del CNR (CNR-IRSA) localizzato nella zona industriale di Bari, mediante l'abbinamento di una pompa di calore con un impianto di prelievo e re-immissione di acqua dalla falda. Dal punto di vista della risorsa geotermica, la verifica delle condizioni di sottosuolo per la realizzazione dell'impianto è avvenuta mediante indagini geologiche-geomorfologiche, idrogeologiche e la realizzazione di prove diagnostiche nel campo pozzi presente nell'area. Nel sito in esame la falda si rinviene alla profondità di circa 12÷13 m da p.c., ovvero a poco più di 2 m sul livello del mare, con una escursione massima di circa 2.2 m misurata nel periodo di osservazione 2008-2010. La temperatura dell'acqua di falda è, in quest'area, mediamente più alta rispetto alle zone limitrofe e pari a 19-20 °C. La conducibilità elettrica, già elevata nei primi metri d'acqua, aumenta con un andamento a gradini con la profondità, arrivando a toccare valori di oltre 7 mS/cm alla profondità di 38 m sotto il livello idrico. Tale andamento è legato al fenomeno dell'intrusione marina; questo giustifica una facies idrochimica clorurato-sodica dominante, nonostante la natura calcareo-dolomitica della roccia serbatoio. Dovranno essere verificate le prescrizioni che le autorità preposte indicheranno al fine di realizzare l'impianto progettato. Nel caso si dovesse utilizzare la porzione interessata dal cuneo di intrusione marina dovranno impiegarsi materiali idonei per evitare corrosione e/o incrostazioni. Per la proposta impiantistica sono state valutate quattro diverse configurazioni impiantistiche utilizzanti due diverse tipologie di pompa di calore e a copertura differenziata del fabbisogno termico: o CASO 1: pompe di calore basate su un ciclo ad assorbimento acqua geotermica-acqua calda modulare ad assorbimento alimentate da gas naturale per la completa copertura dei fabbisogni termici dell'utenza; o CASO 2: pompe di calore basate su un ciclo ad assorbimento acqua geotermica-acqua calda modulare ad assorbimento alimentate da gas naturale per la copertura del 50% della potenza termica di punta dell'utenza; o CASO 3: pompe di calore con ciclo a compressione (acqua geotermica-acqua calda a compressione) alimentate elettricamente per la completa copertura dei fabbisogni termici dell'utenza; o CASO 4: pompe di calore con ciclo a compressione (acqua geotermica-acqua calda a compressione) alimentate elettricamente per la copertura del 50% della potenza termica di punta dell'utenza.

Studio di fattibilità a Mazara del Vallo: questo studio descrive la valutazione geotermica effettuata nel sito di Mazara del Vallo e la proposta tecnico-economica per lo sviluppo di un progetto impiantistico relativo a risorse geotermiche a media entalpia e la realizzazione di un impianto pilota per alimentare una rete di teleriscaldamento per il riscaldamento ed il raffrescamento di edifici pubblici presenti nel Comune di Mazara del Vallo. La verifica della possibilità di utilizzo della risorsa geotermica per la realizzazione dell'impianto, e la valutazione quindi della sua realizzabilità, è avvenuta mediante indagini geologiche, idrogeologiche, geochimiche, geofisiche e la realizzazione di una specifica simulazione numerica dinamica dei parametri fisico-chimici del serbatoio. L'impianto proposto consiste nella produzione centralizzata di energia termica (acqua calda a 90 °C) e la successiva produzione decentralizzata di acqua fredda mediante gruppi frigoriferi ad assorbimento localizzati presso singole e/o gruppi di utenze.

This paper deals with thermo-mineral groundwater of the Mondragone plain (Campania, southern Italy) and the possibility of exploitation of this low enthalpy geothermal resource. In the NW sector of this plain, at the bottom of Mt. Pizzuto, near the sea, there are thermo-mineral waters of sodium-chloride type, sulfureous and rich in CO2 whose recharge is from the Mt. Pizzuto groundwater body which somehow floating on seawater. In the SE sector of the plain, close to the calcareous Mt. Petrino, a 80 m deep well has intercepted, in the carbonate basement of the plain, thermo-mineral groundwater, sulfureous and rich in CO2, as in the NW sector, but displaying a calcium-bicarbonate composition. The chemical and the isotopic analyses allowed to verify that these types of groundwater are due both to meteoric waters infiltration and to enrichment of endogenous CO2 and H2S, at fairly high temperature. In the case of Mt. Pizzuto, the upwelling gas intercepts evaporitic formation and, probably, causes saltwater intrusion, with a peak from June to September. In the case of the Petrinum well, the gases involve "saline formation groundwater", affecting upwards the groundwater body of Mt. Petrino. Moreover, the rising of the gases increases the dissolution of the carbonate aquifer, determining very high values of HCO3 ions in the thermo-mineral groundwater. The upwelling of the gases occurs along the major fault that crosses NE-SW the plain of Mondragone at the southern edge of the Mt. Petrino. Finally, the understanding of the mineralization patterns allowed to identify in the plain the best location for a geothermal exploration well.

Several "target areas" (each one of 20 km2 ) were selected in Southern Italy for geothermal exploration in the frame of Ministry of Economic Development (MISE) and National Research Council (CNR) joint project: Evaluation of Geothermal Potential in Convergence Regions, (VIGOR) founded by POI Programme 2007-2013. In Campania region a selected area is located between the Mondragone town and the southwestern side of Mt Massico, an horst structure constituted by carbonate and terrigenous sediments. In the selected area there are two thermal springs Sinuessae (SN) known since roman time and "S. Maria dell' Incaldana" (SMI). The characteristic of the two springs are for the first one a discharge of 1-2 L/sec and a T of ~ 54°C and for the second one a low discharge increased by wells until 10 L/s, and T of ~ 33 °C The hydrogeochemical analysis of SN and SMI springs show differences in salt concentration, gas and isotope content, which allows to hypothesize different marine influence and hydrographic system. The origin of these two thermal springs is probably related to faults as a preferential pathway for fluid and gas, like in other geothermal areas of southern Italy. The VIGOR geothermal exploration includes detailed geological and geophysical surveys, hydrogeological investigations and explorative wells. Peculiarly, deep hydrogeological investigations (hydrochemical and isotopic characteristics of groundwater plain and its piezometric pattern, permeability features of the springs area and quantification of groundwater resources) have been developed in order to find the most suitable area to drill a geothermal well.

Among the research activities of the Institute for Coastal Marine Environment - "UOS" Taranto, the study the anthropic impact on marine ecosystems and the development of innovative technologies for "environmental remediation" have taken particular significance in recent years. Attention has been paid to the ecological risk analysis for contaminated sites and sustainable management of dredged sediment from coastal areas. The latter issue is of great relevance for the development of harbour areas, especially in Italy. Concerning dredged and contaminated sediments, the easiest option is often the landfill disposal, even if the problem is considerably complicated in relation to the volumes to be managed and/or treated and the simultaneous presence of different types of pollutants. In order to reuse the dredged sediments both civil and industrial sector, in recent years the development of treatment technologies textitex situ has assumed considerable importance. Among these, the "sediment washing" appears very interesting for the removal of toxic heavy metals from dredged sediments. For this purpose research has been started aiming to developing a new method of washing with chelating solutions on samples of sediments in the harbour area of Taranto, it's a site remediation of national interest. Different chelating agents (ethylenediaminetetraacetic acid (EDTA), Ethylenediamine- N,N'-disuccinic acid (EDDS), citric acid) were used at different extraction times. The optimum removal time was found to be 48 h, both with EDTA 0.2 M and EDDS 0.2M. Citric acid was not very efficient for the contamination process. The results suggest that bioavailability and speciation of metals in sediments were the main factors affecting sediment washing. In particular, metal speciation, using sequential extraction technique, were determined before and after washing: this approach was useful to evaluate heavy metals mobility in treated and untreated sediments. The methodology developed could have important implications on industry, also in view of reusing treated material for different purposes (filling, cement production, etc.).

Total metal concentrations (Cu, Ni, Pb, Zn, Fe, and Mn) and their distribution in different chemical forms (speciation) were determined in sediments from the Adriatic Sea in order to evaluate contamination and mobility of metals. The study was carried out on marine sediments collected in two areas of the Adriatic Sea differently influenced by Po river waters. Metal distribution in the study area depends prevalently on water circulation and on organic matter distribution. Among metal levels, significant correlations between copper and zinc and between lead and nickel were found, suggesting common and specific sources. As regards metal speciation, the distribution of different chemical forms changes with the metal. The prevailing zinc phases, for example mobile forms, and sulphide together are greater than 50% of total metal. Nickel is mainly present in sediments as sulphide, and the preferential association of copper with organic matter is evident. Lead and manganese are preferentially found as mobile forms (more of 30% for lead, 40% or more for manganese).

VECTOR project has analysed the main climatic changes in the marine Mediterranean environment. The area studied by the microbiologists in Taranto concerned trends in the development dynamics of Vibronaceae and fecal contamination indicators density in Mar Piccolo samples: water,sediment and mussels.

The spatial distribution of selected metals (Fe, Ni, Mn, Zn, Cu, Pb, Hg and Cd) and their partition in the different chemical forms (speciation) were determined in benthic sediments from Mar Piccolo, Taranto (Ionic Sea, Southern Italy). The aim of this study was to assess the degree of sediment contamination and bioavailability of metals, very important for Italian mussel culture, in a semi-enclosed marine ecosystem. In sediments, grain size distribution, total organic carbon (TOC), and humic (HA) and fulvic (FA) acids contents were also determined. The compounds TOC, HA and FA, in fact, have a great influence on metal complexation. High concentrations of copper, lead, zinc and mercury were found, especially in sediments of the first inlet of Mar Piccolo. Statistical analysis of results shows significant correlation among Cu, Pb and Zn concentrations and the influence of organic matter on the sediment distribution of Cu, Pb and Zn. Metal speciation analysis, carried out with sequential extraction method, shows that Fe and Ni are present in sediments mainly as sulphides. Mn and Pb are present principally in an ion-exchangeable form or bound to carbonate and Cu is associated to organic matter. Metal pollution index (MPI), calculated as a weighed mean of the metal contamination factors in each station, shows that with regard to Cu, Ni, Pb and Zn, some stations investigated are unpolluted (MPI