TABLE OF CONTENT
1 THE SEDI.PORT.SIL. PROJECT..................................................................... 4 2 REGULATIONS AND SEDIMENT TREATMENT TECHNOLOGIES: STATE OF THE ART BASELINE – ISPRA ................................................. 13 3 SEDIMENT CHARACTERIZATION BEFORE AND AFTER SOIL WASHING AND SORTING IN PROTOTYPE - CRSA MED INGEGNERIA SRL - DIEMME ENOLOGIA SPA.................................................................. 20 4 RF THERMAL PLASMA TREATMENT OF DREDGED SEDIMENTS: VITRIFICATION AND SILICON EXTRACTION - ALMA MATER STUDIORUM – UNIVERSITÀ DI BOLOGNA ............................................. 29 5 DREDGED SEDIMENT REUSE PLAN IN RAVENNA TERRITORY (EMILIA-ROMAGNA, ITALY) - UNIVERSITA’ DI FERRARA ................ 39 6 THE SEDI.PORT.SIL TREATMENT PLANT AT THE PORT OF RAVENNA - MED INGEGNERIA .................................................................. 48 7 REPLICATION OF THE SEDI.PORT.SIL METHODOLOGY IN A DIFFERENT EUROPEAN CONTEXT. MIDIA HARBOUR, ROMANIA, BLACK SEA - GEOECOMAR ........................................................................ 55 8 SEDI.PORT.SIL. PROJECT’S DISSEMINATION - ENTE DI GESTIONE PER I PARCHI E LA BIODIVERSITÀ-DELTA DEL PO ............................ 74
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THE SEDI.PORT.SIL. PROJECT Recovery of dredged SEDIments of the PORT of Ravenna and SILicon extraction
The harbour management is a worldwide problem because of the different difficulties that it entails. Sediment management is becoming a critical issue around the world, particularly where conflicts between Ports development, conservation of coastal environments and tourism have to deal with the sustainable use of sediment resources within an Integrated Coastal Zone Management policy. Therefore the maintenance of depths in the harbours channels and basins requires removal of deposited materials (often associated to pollutants). This, in turn, carries with it the needs for major disposal areas for dredged materials. The problems related to the dredging of contaminated sediments, starting from their movement, treatment, final disposal or reuse, lead to a growing interest at European, National and local level (i.e. European Community, National Ministries, Local Authorities and Research Institutions). The intense research and development activities lately carried out, has generated higher efforts to improve the knowledge related to sediments characteristics and their possible treatment in order to make secondary raw materials; however, an integrate approach needed for the sustainable development of harbours sediments is still missing. An assessment undertaken within the SedNet European network demonstrated that the total amount of sediment dredged in Europe reaches 100-200 million cubic meters per year. That material, together with the dredged water, is usually transferred straight into large fill-in basins and polluted water is drained into waste water systems. Polluted sediments are usually sent to landfill sites, with all issues and environmental risks associated to the management of dangerous waste. It is clear that the sustainability of this process should be improved. The SEDI.PORT.SIL. project is intended to demonstrate the efficiency of consolidated treatment technologies coupled with innovative techniques aimed to the recycle and valorisation of port dredged sediments, that can be considered an important resource rather than just a dangerous waste.
1. THE PROJECT From a technical perspective, the project proposes an integrated cycle of actions to be applied to sediments (and associated water) right after the dredging, to reduce the environmental impact and maximize the percentage of material suitable for recycling. Decontaminated sediments could be suitable as raw material in the infrastructure and environmental engineering sectors. The use of polluted sediments for the extraction of silicon is also investigated. A pilot study has been firstly undertaken for some sediment samples dredged from the port of Ravenna, Italy. Afterwards we analysed the applicability of the process at regional level, and we evaluated the process repeatability in a different European context (port of Midia, Romania).The final goal is to develop a guidelines for treated sediment and raw materials reuse, and to assess the feasibility and sustainability for the realization of a treatment plant at the Port of Ravenna. Specific objectives of the project are: 1. to maximize the innovative contribution of the project to the management of dredged sediments within Italian and European administrative and legal frameworks; 2. to demonstrate the efficiency of a treatment process for the decontamination of polluted sediment (soil washing) and associated water (Pump&Treat) on the sediment of the pot of Ravenna. An effective 4
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decontamination process would reduce the amount of dredged sediments and associated water to be managed as waste, and increase the availability of raw material to be re-used; to identify and plan best possible reuses of decontaminated sediment and extracted silicon; to demonstrate the efficiency and the productivity of the extraction of silicon from polluted port sediments through a plasma treatment. This process is highly innovative because it has never been applied to polluted marine sediments; to demonstrate the efficiency of a plasma torch for the decontamination of the finest fraction of dredged sediments (diameter 25÷150 µ). To our knowledge, this innovative decontamination process has never been applied before; to create a Business and a Master Plan to analyse the realization of a treatment plant at the Port of Ravenna, for the treatment of the harbour’s sediments that need to be dredged in next future; to evaluate the repeatability of the process in a different geographical and administrative context in Europe; to raise public awareness on sustainable development issues targeted by the project.
The SEDI.PORT.SIL. project (September 2010 – February 2013) involves 8 beneficiaries (described below) and a co-financer, the Port Authority of Ravenna.
2. THE ENVIRONMENTAL CONTEXT The port of Ravenna Thanks to its strategic geographical position, the Port of Ravenna is one of the most important Italian port, mostly in commercial trade with the East Mediterranean and the Black Sea (approximately 30% of the total national trade total excluding oil products), and plays an important role in commercial trade with the Middle and Far East. Connected with multimodal port, motorways and airports to the main transport network, Ravenna is easily reached from the main Italian and European centres. The port of Ravenna is one of the major Italian ports for break-bulk cargo (e.g. raw materials for ceramics, cereals, fertilisers and meals for animals) and general cargo (mostly timber and coils).To increase its own commercial potentiality, the port Authority foreseen to deep the port in order to accommodate vessels with a draft of up to 44 ft, that means bulk carriers with a 50,000 tons load capacity container carriers with a capacity of over 4-5,000 TEUs. The dredge foreseen will bring to the movement of 11 million m3 of sediments. Solutions for the management of these sediments have to be find in order to reduce disposal of the contaminated component and to gain new materials for possible reuses. Recent geognostical analysis carried out in the port area of Ravenna, shown sediments with different grainsizes and not well layered (associations of sand and silt with different proportions of clay are present); a superficial layer (from about 10 cm to 1 m) of melted sandy silt is present, followed by a more compacted and not well defined layer of different granulometric characteristic but with a higher percentage of sand and, locally, of bioclasts. Below -9/-10 m under m.s.l. a big layer of hazel brown clay is present, with different percentage of silt, often alternating with centimetrical silty sand lens. Portion of sediments presents variable concentration of contaminants, depending of port area (and industrial activities presents) and sediment depth. The type of pollutants is linked to granulometrical characteristics of the materials. Fine and very fine sand sediment fractions are mainly contaminated by hydrocarbons. Silt and clay instead facilitate the accumulation of contaminants, and it it’s possible to find, in addition to hydrocarbons, also heavy metals (e.g. Pb, Hg, As).
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As regard possible reuses of decontaminated sediment, the Emilia-Romagna region coastal zones (in which port of Ravenna is located) offers several opportunities (and needs). First of all, a great amount of sediment is needed for beach nourishment. The coastline is about 130 km long and is entirely consisting of low and sandy beaches edged by dunes, pine forests and valleys. It is affected by beach erosion processes, that led in the last half-century to the realization of several hard coastal structures (e.g. groins, breakwater) and the constant need of beach nourishment. Moreover, coastal area are characterized by big quarries activities (gravel and sand), that need to be fulfilled after the end of extraction operations and several infrastructures projects with an great demand of foundation materials. It is important to note that this coastal area presents, at the same time, also other great amounts of sediment to be treated, recovered and valorised for reuses; among them: several marinas along the coasts that need of dredging activity for their operation maintenance, land reclamation projects in contaminated sites.
Figure 1: Views of the Port of Ravenna
The port of Midia The test area is the Romanian Harbour of Midia, presents several peculiarities: •
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Historical. Built during the Second World War and extended during the late 1970`s, with the main purpose of becoming one of the major hydrocarbon sea terminals along the Black Sea, during the 1980`s the harbour was active as an oil and general merchandise terminal. After, the harbour environment has suffered influences from three economic types of systems (communist – transition – market economy), with significant heights and lows. Natural. While from Midia Harbour southwards the entire coast has been strongly developed by humans, the northern part of the coast is mainly wild, as it is a part of the Danube Delta Biosphere Reserve (almost 6000 square kilometres). Mineralogy. Most of the sediments accumulated in the area are fine – grained Danube – borne alluvia, retransported towards this area by the littoral longshore current. The mineralogical composition is specific, as besides the rich contents of quartzitic Danube sediments and calcium carbonate fraction (mainly from the shell fragments), there are also contents of Danube – borne heavy minerals – such as garnets. About twenty kilometres northwards (and also updrift) there are significant accumulations of such heavy minerals which were exploited during the communist period.
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Social, political and legislative framework. The lack of a strongly enforced legislation has been translated also into a lack of historical data regarding the quality of water and sediments.
Figure 2: Views of the Port of Midia
3. THE STRUCTURE OF THE PROJECT Each of the project objectives listed at previous section is pursued through a set of specific actions (Figure 3). Scheduled actions and related objectives are described below: Action 1: Project Management It aims to ensure project correct management and efficient implementation of project activities and to facilitate achievement of expected results and objectives. It is organized in four sub-actions: (a) Project management and coordination; (b) Project monitoring and evaluation through a specific program and measurable indicators (Objectively Verifiable Indicators, OVIs), interim reports and evaluations; (c) auditing, through an independent auditor; (d) development of the “After-LIFE communication plan”. Action 1
Action 3
Action 2
Action 4
Action 6
Action 5
Action 7 Action 8
Figure 3: Relationship among project’s actions
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Action 2: Preparatory action: state of the art baseline The action aims to carry out a literature review in order to create the baseline for the development of the overall project. It includes a literature research on the following points: (a) a detailed characterization of Port of Ravenna sediments, (b) existing legal and administrative frameworks for the management of dredged sediments; (c) best available technology for the treatment and decontamination of dredged sediments; (d) best available technology for the extraction of silicon. A detailed knowledge of the state of art in these sectors is required to maximize (and to prove) the innovative contribution of the project to the sustainable management of dredged sediments. Action 3: Demonstration activity for the sediment treating process Activities included in this action aim to demonstrate the efficiency of the proposed sediment decontamination process through a prototype application. Sub-actions are: (a) the dredging of 3 samples (TEST) of sediments and associated water with different expected pollution levels; (b) A detailed analysis of every sample (pre and after treatment), including physical-chemical, micro-biological, ecotossicological and mineralogical tests. That analysis is required to check the efficiency of the decontamination process; (c) Sediment (and water) treatment through an prototype plant, built on purpose for this study. Action 4: Sediment plasma treatment This action aims to demonstrate the efficiency and the productivity of the extraction of silicon from polluted port sediments through a plasma treatment and to demonstrate the efficiency of a plasma torch for the decontamination of the finest fraction of dredged sediments. Sub-action are: (a) Numerical simulation of the process for the identification of the optimal process parameters; (b) Plasma treatment of sediment inside graphite crucible; (c) In-flight plasma treatment of sediment using an injection probe. Action 5: Sediment re-use plan This Action aims to identify and plan best possible reuses of decontaminated sediment and extracted silicon though the following sub-actions: (a) A detailed literature review about dredged material reuses and the Ravenna coastal zone needs for sediment; (b) field surveys and analysis for the selection of suitable pilot sites in need for beach nourishments along the Ravenna’s coasts; (c) field surveys and analysis for the selection of suitable quarries in need for restoring interventions in the Ravenna’s area; (d) regional planning analysis for infrastructural reuse evaluation, (e) development of guidelines for treated sediment reuses. Action 6: Business Plan for the treatment plant at the port of Ravenna As first, a treatment plant able to manage all sediments dredged from Ravenna’s Port is designed in detail (sub-action 6a). The Business Plan undertakes an economic analysis of the new plant and it sets a strategic plan for its optimal exploitation (sub-action 6c). To that purpose, a Master Plan is drawn up, in order to evaluate and quantify all potential reuses of decontaminated material, socio-economic benefitsand potential new sources of sediment once those from the Ravenna Port will be finished (sub-action 6b). Action 7: Replication of the SEDI.PORT.SIL. methodology in a different European context The area chosen is the Harbour of Midia, on the Black Sea coast, Romania. The different context (historical, natural, sedimentological and socio-political) allows to analyse the strengthens and weaknesses of the project, in order to improve it and make it suitable for different applications in Europe. Sub-action are: (a) Inventory of existing data and new sediment characterization; (b) Sediment treatment evaluation; (c) Local reuse of decontaminated sediments; (d) feasibility study for the completion of a treatment plant installation in the Midia Harbour area. 8
Action 8: Dissemination A special attention is given to the dissemination of aims and results, which happens before, during and after the whole project life. Dissemination is pursued through: (a) the organization of meetings and workshops with stakeholders, target groups and co-financier; (b) informative bilingual brochures and other dissemination material, distributed at large scale; (c) a web-site dedicated to the project that is kept updated even after the end of the project; (d) a preparation of a set of guidelines for project repeatability elsewhere.
4. PARTNERS OF THE PROJECT Coordinating beneficiary: MED INGEGNERIA SRL Since 1992 MED INGEGNERIA (MED), an Italian leading consulting company in the field of water resources management, coastal hydraulic and geophysics, environmental engineering/planning, has carried out hundreds of national and international projects while providing its clients with the highest standards of quality. Throughout the years MED has consistently expanded and now regularly employs a staff of over 50 specialists in 5 offices throughout Italy. Moreover, thanks to stable cooperation agreements and direct stock ownership, MED can count on a vast network of Italian and International consulting firms enabling the company to assist clients independently from the project’s size or nature. In the most recent years, MED international activities have experienced a significant growth. Through its involvement in projects funded by international and governmental institutions (e.g. European Commission, UNEP, UNESCO, Italian government) MED INGEGNERIA is presently undertaking assignments in over 10 countries world-wide. MED INGEGNERIA core business relates to coastal and maritime, water resources, and environmental engineering/planning. During the years, MED has focused on the solution of marine and coastal environments problems (deltas, estuaries, lagoons, harbours) and the coastland areas geographically connected to and functionally dependent on these environments. MED INGEGNERIA has carried out several surveys for sediment characterization, both onshore and in harbour areas; its experience is fundamental during the development of the project. Furthermore, MED has specialized knowledge in the field of civil/environmental engineering, earth science, ecology, river and marine hydrography, covering the entire design process from the survey and pre-feasibility phase, to the executive design and the work direction. Associated Beneficiaries
University of Ferrara – Earth Science Department Since more than ten years, the Earth Science Department Operative Unit of Ferrara University develops researches about the morphodynamic, sedimentology, management and protection of littoral areas through numerous national and international projects concerning the evolution of beaches, coastal dunes, river delta mouth and wetlands like the “assessment of the coastal erosion along the Albanian coast” funded by UNEP (2000). Furthermore, the O.U. collaborates with Regional, Local and Government Authorities, for coastal management plans applying new defence systems (i.e.core-fortified coastal dunes, wood poles, etc). For instance they actively contributed to the realisation of the Master Plan of the Ravenna territory and of the Parco del Delta del Po of the Emilia-Romagna region or they analysed the sedimentological and morphological variation of the coast due to works of beach protection and restoration (MIUR).
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The group is composed by scientists and researchers specialised in applied geomorphology and remote sensing. The experts, from different scientific fields (geomorphology, geology, natural science, biology and engineering), gained experiences in the development of new methodologies for beaches and dunes erosion vulnerability and risk assessment and coastal flooding induced by extremes events also referred to climate changes (e.g. Metaponto project). The group has participated to numerous studies dealing on the impacts due to the gas and water extraction, realization of pipelines, construction of defense structure for the coastal zone and beach nourishment (“design of the coastal defenses in front of Gorino lighthouse and its monitoring”, Region Emilia-Romagna). They also participated to a project for the restoration of the lagoon of Goro (It) and the re-qualification of the lagoonal sediments (Ferrara Provinicia). Finally the responsible of the work group, Prof. Simeoni, was leader of the IGCP-UNESCO project number 515 dealing on “Vulnerability and resilience assessment of coastal zone in Mediterranean and Black Sea areas related to the forecast sea level rise for management purposes”.
University of Bologna – DIEM Department The University of Bologna DIEM Department is involved in educational and research activities in many fields of Industrial Engineering. The Department is active in research, technological development and education in the fields of Mechanical, Nuclear/Energy Plants, Aviation, Management and Metallurgical Engineering. Basic research is joined with an intense applied research action, coming from partnerships with industrial sectors, and due thanks to DIEM Laboratories and related equipment. The Research Group for Industrial Application of Plasmas of the DIEM Department is active in the field of modeling, design and diagnostics of plasma sources and plasma processes and includes in its facilities a Radio Frequency plasma torch with reaction chamber and a plasma cutting system. This Research Group combines strong physical mathematical knowledge of plasmas that is used for the development of numerical models that can simulate almost all current technological plasma sources and processes. The most part of these models are acknowledged to be the “state of the art” by the thermal plasma research community. This Research Group is currently involved in industrial collaborations in the fields of: plasma cutting, nanoparticles production, modeling of metallurgical arc furnace.
Po Delta Park The Po Delta Park in Emilia-Romagna (established by the Regional Law 27/88) is part of the system of the Protected Areas in Emilia-Romagna. The Park is divided into six different zones that develop around the southern portion of the Po Delta, the rest belonging to the Veneto Region, along the coast near Ferrara and Ravenna and inland near Argenta. The Po Delta Regional Park of Emilia-Romagna has natural values, cultural and historical landscape of both national and international interest. Inside the perimeter of the Park there are residues of Mediterranean forests, hygrophilous woods, coastal lagoons, marshes, freshwater and brackish ones, salt marshes, banks of rivers and canals, but also large portions of the coastal sandbars, coastal pine forests and ancient dunes. It includes the less populated areas of coastline and more natural values of the entire Region of Emilia-Romagna, but also densely populated tourist centres. This highly complex environment is reflected in an extraordinary diversity of species, for many of which the Delta represents a real stronghold at European or National level. 10
Up to 2011, the Park has been managed by the Emilia-Romagna Regional Po Delta Park Consortium, composed by two Provinces (Ferrara and Ravenna) and nine Municipalities (Comacchio, Argenta, Ostellato, Goro, Mesola, Codigoro, Ravenna, Alfonsine, Cervia), whose boundaries lie within the Park. Recently, since January 2012, according to the Regional Law n. 24 of 23/12/2011, the Authority for the management of the Protected Area will be the Managing Body for Parks and Biodiversity - Delta del Po.
Institute for the Protection and Environmental Research – ISPRA ISPRA is a public scientific institute that supports the local administrations and authorities in managing activities related to the marine protected areas, port dredging and fishery. ISPRA represents the technicalscientific consultining bureau of the Ministry of Environment for issues related to the marine environment, being involved also in the evaluation of sediments quality as well as in the authorization process for subaquatic disposal of dredged sediments from Italian ports and harbours. Due to the high skill in the subject of interest, ISPRA has been given by the Ministry of Environment the task to draw up a technical framework on characterization and handling of marine dredged sediments. Furthermore, the Decree of the Ministry of Environment (468/01) “National Program of Remediation and Environmental Recovery” gave ISPRA the responsibility for characterization of marine and brackish areas (small and large ports, lagoons, coastal areas ) located within the sites identified as “national prioritycontaminated sites”. ISPRA has a strong knowledge and wide experience on environmental issues related to dredging activities and dredged sediments, covering a wide range of aspects: design of sediment characterization campaigns, identification of appropriate dredging strategies, definition of the analytical methods for sediment characterization, study and experimentation of technologies for sediment reuse.
GEOECOMAR The National Institute of Marine Geology and Geo-ecology - GeoEcoMar of Romania, is a researchdevelopment institute established in 1993, under the co-ordination of the Romanian Ministry of Education and Research. The main activities of GeoEcoMar relate to marine, deltaic and fluvial environmental and geoecological studies regarding the ecosystems of the River Danube - Danube Delta - coastal Black Sea geosystem; the environmental impact of anthropogenic structures (civil and hydrotechnical works) that are located along the Danube course and in the Danube Delta; geological-geophysical-geoecological survey of the Black Sea as well as of other marine areas; study of natural hazards in Black Sea environment (submarine landslides, tsunami, major storms, etc). The research work undertakend by GeoEcoMar includes: Environmental and geo-ecological studies; Studies on Land-Sea and River-Sea interactions and coastal processes; Scientific support and technical assistance for littoral and offshore marine engineering; Paleoecological and paleo-environmental studies; Studies on geological capture and storage of CO2; Past and present environmental and geological impacts of t global sea level changes. GeoEcoMar has started its European and international co-operation in 1991 with the French Institute of Marine Biogeochemistry in Montrouge and the Cousteau Team. Afterwards, GeoEcoMar enlarged its scientific international participation in the EU Framework Programmes (FP) 4, 5, 6 and 7, becoming also a European Centre of Excellence under FP 5. It is also present in other European funded projects such as SEE project ECOPORT 8, on the environmental quality issues of Pan-European Corridor 8 ports. Other significant international scientific cooperation projects have been performed in the GEF-UNDP Black Sea 11
Environmental Programme, NATO Scientific Cooperation Programme, as well as under the framework of bilateral co-operations with France, Germany, Italy, Switzerland etc., GeoEcoMar having in these a central role of regional co-ordinator or national contact-point.
DIEMME Enologia S.p.A. DIEMME Enologia S.p.A. a private company founded in 1923 is part of industrial group FUTURA Immobiliare e Finanziaria S.p.A. From its origin, manufacturing equipment for the winemaking industry, the company developed during its long history into innovative business area, to include equipment and technologies for extraction, classification and solid – liquid separation. DIEMME Enologia S.p.A. is specialized on design, development and realization of complete plants with “Soil-Washing Process Technology” for the remediation of contaminated sediments and contaminated soils. DIEMME Enologia S.p.A. operates on the market with a perspective of technologic innovation, offering provable and guaranteed results thanks to R&D laboratory and test on Industrial Pilot Plant. Understanding customer’s needs and providing bespoke turn-key solutions with a green approach, contaminated sediment and soil are valuable products and not only waste. DIEMME Enologia S.p.A. is operating under a quality system following UNI EN ISO 9001:2008 and has obtained the qualification SOA for execution of public works.
CRSA MED INGEGNERIA srl The Centro Ricerche e Servizi Ambientali C.R.S.A. (Centre for Research and environmental Services) located in Marina di Ravenna was founded in 1993 by Montedison Group and it is now (since 2009) part of MED INGEGNERIA Group. It represents an innovative research centre specialized in consulting services and analysis for industries, private companies and local authorities. C.R.S.A. provides a large range of services and solution in the field of environmental and health surveying and protection. C.R.S.A. laboratories provide the possibility to implement pilot site physical models (at reduced scale) for the design, construction, execution and analysis of soil remediation activities. Affiliated with the University of Bologna, it guests researchers, graduate students and students from different scientific disciplines. C.R.S.A. laboratories are certified by the National accreditation body ACCREDIA (certificate no. 0644) since 2005 for the tests execution. Moreover, C.R.S.A. MED INGENGERIA, being an organization with quality and environment management system certified by CERMET following UNI EN ISO 9001:2008 and UNI EN ISO 14001:2004 (reg n.8065), has obtained the certification for "consulting and research services in the environmental field and for chemical, physical, microbiological analysis; analysis and study of environmental ecotoxicology; planning and implementation of pilot plants for the soil recovery process study".
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REGULATIONS AND SEDIMENT TREATMENT TECHNOLOGIES: STATE OF THE ART BASELINE ISPRA Dastoli S., Geraldini S., Giaime F., Renzi P.
[email protected]
The SEDI.PORT.SIL. project is intended to demonstrate the efficiency of consolidated treatment technologies coupled with innovative techniques aimed to the recycle and valorization of port dredged sediments, that can be considered an important resource rather than a waste. The project, starting from the study area of the Port of Ravenna, aims at the definition of a production chain consisting of chemical-physical treatment systems and a thermal plasma treatment, for the decontamination of the dredged polluted sediments and metallurgical grade silicon extraction from sediments, and it has the purpose to promote the treated sediments reuse for environmental recovery and morphological restoration interventions both upland and in coastal areas and for civil engineering uses. For the development of the overall project, to maximize and to prove the innovative contribution of the project to the sustainable management of dredged sediments, a literature review has been realized in order to create the state of the art baseline about rules governing the management of marine sediments and available technologies for their treatment and valorization. For this purpose ISPRA investigated: 1. the legal framework concerned with dredged sediments and contaminated sediments, and their possible reuse at European, national and local levels; 2. the available treatment systems scenarios at pilot scale and/or real scale, both at national and international level and a critical revision of the treatment techniques to evaluate the different contaminant removal efficiency and to identify the most suitable treatment techniques for the Port of Ravenna sediments; 3. the existing technologies available for silicon extraction from sediments to gain metallurgic silicon for commercial use.
1. SEDIMENT MANAGEMENT: LEGAL AND ADMINISTRATIVE FRAMEWORK An analysis of legal framework at national and international level has been carried out, aiming at identifying normative tools that can be tackled in an organic and comprehensive management of the problem of the dredging of sediments, in particular, to their valorization. At international level there is not a specific directive on the subject, but it is possible to infer general indications in some international conventions (the London Convention, Barcelona Convention for the Mediterranean area, the Oslo and Paris Convention for the area of the North-East Atlantic, the Helsinki Convention for the Baltic Sea area), aimed at the prevention of marine pollution and that tend to promote alternative management options, introducing the concept of sediment as a "resource" and not as "waste " and, in the European case, some directives that can be grouped under two main areas of waste and water (91/692/EC Directive, Landfill Directive 1999/31/EC, Directive 2008/98/EC Waste, Directive 2008/98/EC, 2000/60/EC, WFD, etc..). Consistent with the international trend illustrated, also at national level, observes a substantial lack of specific legislation governing the management of dredged sediments, especially in relation to their recovery and reuse. To find useful information for management purposes it is necessary to follow a structured path through various standards, such as: Decree of the Ministry of the Environment 24/1/1996, applicable throughout the country, which governs the preliminary activities for the issuance of permits for controlled
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release of dredging sediment at sea; Decree 152/2006 (Environmental Standards) and subsequent amendments, applicable throughout the national territory, in which there are regulatory elements in the management of waste. In particular, art. 109 of Decree 152/2006 “Offshore dumping of material resulting from dredging activities and from the laying of cables and pipelines” states that the authorization, released by the Ministry of Environment, for sea disposal of material dredged from marine or brackish-water beds or coastal terrains can be obtained only when it is demonstrated that it cannot be used, due to technical or economic reasons, for beach nourishment, or recovered or otherwise disposed, according to the London Convention concept of sediment as resource. Moreover, the art. 1, paragraph 996 of the Law 27 December 2006, n. 296, applicable within the Sites of National Interest, regulates the management of sediments into confined disposal facilities. At the end of April 2012 a revision of the Italian legal framework has been made on the basis of a specific law updating, that introduces some new management options for dredged materials: • art. 48 of the Decree-law 24 January 2012, n. 1, “Urgent provisions on competition, infrastructure development and competitiveness”, converted into law , with amendments, by Law 24 March 2012, n. 27: this rule updates and replaces the art. 1, paragraph 996 of the Law 27 December 2006, n. 296, regarding to harbours and coastal areas within Sites of National Interest, and summarizes existing laws regarding to harbours outside Sites of National Interest. • art. 24 of the Decree-law 9 February 2012, n. 5, “Urgent provisions on development and competitiveness”, converted into law by Law 4 April 2012, n. 35: this rule is a revision of art. 109 of the Decree 152/2006: Regions have the legal and technical competence on open water sea disposal of sediments, except actions on protected areas. The art. 48 of the Decree-law 24 January 2012 confirm, within the Sites of National Interest, the solution to manage dredging material by sea disposal, reusing it for beach nourishment, refilling it into CDF with an appropriate impermeabilization, introducing important innovations too. For these management options can be used dredging material with specific suitable characteristics, but also different grain size fractions obtained by separation with physical methods and dredging material after treatment and contamination removal. It’s possible to manage dredging material refilling it into CDF also in different harbour far away from the origin. Dredged material, with suitable characteristics, can be used for capping and ashore uses, in the case of contamination levels lower than col. A and B Tab. 1 attachment 5 Part IV of the Decree 152/2006, according to the final destination, and to leaching test regulated by Ministerial Decree 5 February 1998. Moreover it’s possible to use dredging materials with an high content of sulfates and chlorides within saline phreatic zone, under Local Authority permission. Furthermore other innovations are announced: • Paragraph 5: the purpose to revise the Ministerial Decree 7 November 2008 (that regulates dredging activities within Sites of National Interest) about characterization methodologies for sediments that have to be dredged; • Paragraph 6: an Interministerial Decree reporting “Rules and laws on dredging materials and their reuse”. In the case of harbours not included into Sites of National Interest, the art. 48 mentions all different management options, quoted into other laws, like as open water sea disposal, beach nourishment and refilling into CDF or other harbour structures, including also other specific uses, not mentioned before: nearshore dumping of sand and reuse for coastal zone reconstruction. There are also some examples of regional directives regarding dredging sediment management such as the Mud Protocol of Venice, 1993, and the resolution of Marche Region n. 255, 2009, “Guidelines for management of dredged material in harbours and coastal areas in Marche Region”.
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In addition to the environmental directives, a technical reference for the management of dredged sediments is the APAT-ICRAM “Manual for the handling of marine sediments”, which summarizes and outlines actions for a sustainable management under the current legislation (art. 109 of the Decree 152/2006). This technical reference was in fact recommended to the regions by the Ministry for the Environment, Land and Sea for the implementation of the art. 109.
Figure 1: Technical manual for the handling of marine sediments in Italian harbours (2007)
2. TECHNOLOGIES FOR THE TREATMENT AND DECONTAMINATION OF DREDGED SEDIMENTS According to the project purpose, an investigation of the available treatment systems scenarios at pilot scale and/or real scale, both at national and international level, has been conducted aimed at the evaluation of the different contaminant removal efficiencies and at the identification of the most suitable treatment techniques for the Port of Ravenna sediments. Nowadays, technologies used for the treatment of contaminated sediments are those applied for soil; unfortunately the specific characteristics of sediments (large amount of clay and organic content, mineralogy, possible salinity, etc.) can reduce contaminant abatement or significantly increase costs. In the choice of treatment technologies, it is therefore necessary to identify the most appropriate technical solutions applicable to various types of contaminated sediment, taking into account the grain size composition and type of contaminants, even thinking about the application of a sequence of different technologies, aimed at sediment cleaning up for their recovery and reuse, trying to minimize the volumes to landfill. Once dredged the contaminated sediments, treatment occurs in two distinct phases: pre-treatment and treatment itself. The pre-treatment may include the separation of different particle size classes and / or the elimination of water (dewatering) and can help to: • make the material homogeneous in order to obtain a limited variability of the physical characteristics (specific weight, particle size) such as not to impair the efficiency of the treatment technologies; • reduce the volume to be transported, to be sent to future treatments or to landfill. For the treatment phase there are many technologies that can be used depending on the nature of the contaminants and the physical characteristics of the sediment. In general, the treatment process is realized with a combination of chemical, physical and biological treatments. The biological treatments are based on biodegradation: biological oxidation of the biodegradable organic substance by particular microorganisms such as fungi and bacteria that degrade complex organic compounds
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into simpler forms. This is a process that occurs naturally in soils and sediments, but can also be induced by administering specific microorganisms (eg bacteria). Biological processes originate some residual flows (process water, sewage, air emissions) to be treated upstream of final disposal. The main biological treatments are: bio-pile, bioreactors, bioslurry, landfarming, phytoremediation (phytoextraction, phytodegradation, phytostabilization).
Figure 2: Separation treatment – pilot plant
The chemical-physical treatments are differentiable in processes of physical nature, which promote contaminants separation from the solid matrix of the sediment, and processes of chemical nature, in which the chemical structure of the contaminants is modified to obtain compounds less toxic or more easily separable from the matrix of the sediment and, finally, processes of electrochemical and chemical-physical nature. The main chemical-physical treatments are oxidation, solvent extraction, extraction by flotation, reduction, chelation, solidification/stabilization, sediment washing. The thermal treatments allow to remove, destroy or immobilize a wide range of organic and inorganic contaminants present in the sediment; in general in the thermal desorption and in thermal destruction the processing temperatures are respectively less than 550 ° C - 650 ° C and between 600 ° C and 2000 ° C. The main thermal treatments are thermal desorption, incineration, pyrolysis, gasification, oxidation at high pressure, vitrification, plasma incineration. Regarding to sediments collected in Port of Ravenna, on the basis of analytical results, they can be treated and separated into two main classes: SAND (size >75 µm) and SILT (particle size < 75 µm), with different composition in terms of chemical distribution. In particular, it can be observed that: • sandy fraction resulted unpolluted and without microbiological faecal contamination. The ecotoxicology responses were probably influenced by some residual of original sediment and resulted in B code. • silty fraction presented high level of organics (C>12 and PCB only in RED test), coming from the original sediment. The prototype provided by the project was designed for grain size separation and progressive washing of Ravenna port sediment, meanwhile concentrating the contaminants into the finest fraction. During the sieving and the following filterpress process, an effect of physical concentration has been produced by the separation of unpolluted fraction. The sediment washing is a treatment process aimed to create conditions for the mobilization of contaminants by washing with extractants agents. The contaminants are transferred in an aqueous liquid fraction, optionally added with appropriate reagents. The process takes place as a result of two mechanisms: the dissolution and dispersion of contaminants in the extraction liquid.
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The type of extractants agents used in washing treatments depends on the nature of the contamination and on the manner in which the various contaminants are bound to the solid material: the behaviour of contaminants within the matrix of a soil or sediment is closely related to mineralogical composition, presence of organic matter, pH, redox conditions, conditions of aging, etc.. The agents most extractants used are acids, bases, surfactants, solvents, chelating agents, reducing agents to promote mechanisms opposed to those that bound contaminants within the matrix of the soil or sediment. Among the pollutants for the removal of which can be applied to washing treatments include heavy metals, halogenated solvents, aromatic compounds, polychlorinated biphenyls (PCBs), phenols, pesticides, diesel fuel and oils. Since after the washing treatment a residue of contamination due to hydrocarbons has remained, a treatment of landfarming has been studied to reduce this concentration. The additions of landfarming treatment, used for sediments of the port of Ravenna, permitted to reduce the hydrocarbons contents: at the point of view of final TPHs level, this treatment allowed to significantly reduce the organics concentration. The treatment of landfarming is the realization of a basin of treatment confined and provided with bottom draining. The humidity of the soil is kept constant with controller irrigating; the rate of degradation of contaminants is greatly depending on the season, important is the mixing activity of the layer of contaminated sediment which has a favorable effect on the aerobic biodegradation. This technique is successfully applicable to sediments contaminated by hydrocarbons and mineral oils and remediation times is of the order of months. The material subjected to this treatment must be uniform, permeable and mostly sandy.
3. SILICON EXTRACTION TECHNOLOGIES Silicon, its use and the existing technologies available for silicon extraction to gain metallurgic silicon for commercial use have been investigated. Silicon, a chemical element which has the symbol Si and atomic number 14, is the most common metalloid. It is more widely distributed in dusts, sand planets as various forms of silicon dioxide (silica) or silicates. Silicon is so one of the world’s most abundant element, but it must be obtained through extraction processes. Moreover, refining techniques must be applied before the element can be used in electronics or photovoltaic industry. Depending on the purity of silicon it is possible to do a classification: in general we speak about metallurgical grade silicon (MG-Si), approximately 98% pure; solar grade silicon, already sufficiently pure for photovoltaic cells; electronic grade silicon (EG-Si), high purity silicon, usually intended to electronics industry. Metallurgical grade silicon (MG-Si) is commercially prepared by the reaction of high-purity silica with wood, charcoal, and coal (so called carbothermic reduction) in an electric arc furnace using carbon electrodes. At temperatures over 1.800 °C the carbon in the aforementioned materials and the silicon undergo the chemical reaction: SiO2 + 2 C → Si + 2 CO. Liquid silicon collects in the bottom of the furnace, which is then drained and cooled. The product consists of 98-99% silicon and about 1-2% of impurities which are mainly iron, aluminum, phosphorus, calcium, titanium, carbon and boron. The consumption of electric energy is 11-13 kWh/kg produced MG-Si. The use of silicon in photovoltaic technology and semiconductors requires a higher purity than that provided by metallurgical grade silicon. Therefore, over the years, numerous studies have been conducted on techniques of purification that can produce high-quality silicon by silicon of lower purity. Traditionally, metallurgical grade silicon (MG-Si) has been purified by the Siemens process which gives electronic grade (EG) silicon called polycrystalline silicon, or just polysilicon, and has a purity of 99,9%.
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After purifying, ultra pure monocrystalline silicon is obtained by a Czochralski (Cz) crystal pulling process or by Float Zone (FZ). At the present time, Float Zone (FZ Si) is used for premium high-efficiency cell applications and Czochralski method (CZ Si) is used for higher-volume, lower-cost applications. The Siemens Method has the potential to directly produce solar grade silicon without any CO2 emission and at much lower energy consumption. In this method, high-purity silicon rods are exposed to trichlorosilane at 1150 °C. The trichlorosilane gas decomposes and deposits additional silicon onto the rods, enlarging them because 2 HSiCl3 → Si + 2 HCl + SiCl4. Silicon produced from this and similar processes is called polycrystalline silicon. Polycrystalline silicon typically has impurity levels of less than one part per billion. The Siemens process is highly energy consuming (120-160 kWh/kg produced polysilicon). The Czochralski method is named after J. Czochralski, who determined the crystallisation velocity of metals by pulling mono- and polycrystals against gravity out of a melt which is held in a crucible. The pull-frommelt method widely employed today was developed by Teal and Little in 1950 . The Czochralski method begins by melting high purity polysilicon (SG-Si) with additional dopants as required for the final resistivity in the rotating quartz crucible. During the production process the quartz crucible (SiO2) gradually dissolves, releasing large quantities of oxygen into the melt. More than 99% of this is lost as SiO gas from the molten surface, but the rest stays in the melt and can dissolve into the single crystal silicon. Float-zone silicon is a high-purity alternative to crystals grown by the Czochralski process. The concentrations of light impurities, such as carbon and oxygen, are extremely low. Another light impurity, nitrogen, helps to control microdefects and also brings about an improvement in mechanical strength of thewafers, and is now being intentionally added during the growth stages. The Float Zone (FZ) method is based on the zone-melting principle and was invented by Theuerer in 1962. The production takes place under vacuum or in an inert gaseous atmosphere. The process starts with a highpurity polycrystalline rod and a monocrystalline seed crystal that are held face to face in a vertical position and are rotated. A necking process is carried out to establish a dislocation free crystal before the neck is allowed to increase in diameter to form a taper and reach the desired diameter for steady-state growth. Unlike CZ growth, the silicon molten Zone is not in contact with any substances except ambient gas, which may only contain doping gas. Therefore FZ silicon can easily achieve much higher purity and higher resistivity. Crystal pulling as well as zone melting are very effective purification methods, but are also extremely expensive and require at least double purification of the metallurgical grade silicon before satisfactory solar cell quality is obtained. A further system of silicon purification is the use of a plasma torch with the addition of reactive gases, which leads to the volatilization of impurities on the surface of liquid silicon. The plasma treatment can be used for the inertization of the sediment and for the extraction of metallurgical pureness degree silicon. The high temperature of the plasma discharge (about 12.000 K in the core and 3.000 K in the tail) causes the melting of the sediment sample, together with the dissociation of all the complex molecules and the evaporation of volatile metals (lead, zinc, cadmium, mercury).
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4. REFERENCES Aberle A. G. et al., Recent Advances in Policrystalline Silicon Thin Film Solar Cells on Glass at UNSW, 31th IEEE PV Specialist Conference, Orlando(FL), 3-7 September 2005 Alemany, Trassy, Pateyron, K.-I. Li, Y. Delannoy “Refining of metallurgical-grade silicon by inductive plasma” SolarEnergy Materials & Solar Cells 72 (2002) 41–48 Apitz, S.E., (2010), “Waste or resource? Classifying and scoring dredged material management strategies in terms of the waste hierarchy” - J. Solils Sediments 10: 1657-1668 Bergmann H. (2004), “European sediment regulations: Gaps and bridges” - Venice SedNet Conference Bortone G., Palumbo L., 2007. Sustainable Management of Sediment Resources. Volume II – Sediment and dredged material treatment, Elsevier, Oxford De Boer P. (2010), Rijkswaterstaat, Ministry of Transport, “Dredged Material and Legislation Workshop Udine Flamant, Kurtcuoglu, Murray, Steinfeld “Purification of metallurgical grade by a solar process” Solar Energy Materials & Solar Cells 90 (2006) 2099–2106 Kothe (2003), “Existing sediment management guidelines: an overview” - Journal of Soils and Sediments, 3: 144–162 Madalinski K., 2008. “Innovation In Situ Technologies for the Remediation of Contaminated Sediments” – EPA, Federal Remediation Technologies Roundtable Meeting Mink et al. (2006), “Impact of European Union Environmental Law on Dredging” - Terra et Aqua, number 104 Netzband A. (2010) “Sediments in European River Basin Management Plans SedNet” - ESPO Workshop, Brussels PIANC (2009), ”Dredged material as a resource: options and constraints” Report n. 104-2009, Brussels Ringeling R. H. P., HJ. H. de Best, A. L. Hakstege, "Treatment of contaminated sediments in Netherlands", in Proc. of 5th International Conference on the Environmental and Technical Implications of Construction with Alternative Materials, ed. G. Ortiz De Urbina INASMET and H. Goumans ISCOWA, San Sebastian, Spain, 4-5-6 June 2003 SedNet Conference (2011), “Dredging and sediment management European Sea Port” - 7th International SedNet Conference - Venice Workshop on dredged material and the implementation of the new EU waste directive, (2010) - Brussels
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SEDIMENT CHARACTERIZATION BEFORE AND AFTER SOIL WASHING AND SORTING IN PROTOTYPE CRSA MED Ingegneria srl (1) - Diemme Enologia spa (2) Campisi T.1, Danilo Bettoli D.2
[email protected];
[email protected]
1. INTRODUCTION The total amount of sediment dredged in Europe reaches approximately 200 million cubic meters per year (SEDNET, 2011). Polluted sediments are usually sent to landfills, with all issues and environmental risks associated to the management of wastes. It is clear that the sustainability of this process should be improved. The SEDI.PORT.SIL. project (Recovery of dredged SEDIments of the PORT of Ravenna and SILicon extraction) has been conceived to demonstrate an integrated approach for the sustainable management of sediments dredged from ports, and specially from the Port of Ravenna (11 million of m3 will be dredged in the next 3 years) (Ravenna Port Authority, 2011). Specific objectives are to demonstrate the efficiency of a physical, chemical and biological treatment processes for the decontamination of polluted sediment and associated water and to test the efficiency and the productivity of the extraction of metallurgic grade silicon (MGS) through a plasma treatment on sediments. MED Ingegneria is the Coordinating beneficiary of the project started in September 2010 (end foresees in February 2013), financed by the European Commission through Life + founds. Other associated beneficiaries are the universities of Bologna and Ferrara, Diemme Enologia S.p.A, the Institute for Environmental Protection and Research (ISPRA), Management authority for the Parks and Biodiversity - Po Delta, GeoEcoMar (Romanian Institute of Geo-ecology) and CRSA MED Ingegneria srl. A large group of environmental projects are being currently carried out in the European Union to implement, update and develop the EU environmental policy and legislation, with the financial help of the EU’s funding instrument for the environment, the LIFE+ programme. In particular, the “Recovery of dredged SEDIments of the PORT of Ravenna and SILicon extraction” project (SEDI.PORT.SIL), represents a highly innovative alternative to the traditional treatment of the dredged polluted sediments. This project is aimed at laying down clear guidelines for the sustainable management of dredged sediments, establishing the basic pillars for the realization of a treatment plant in the port of Ravenna, and demonstrating the efficiency of some consolidated technologies for the treatment of sediments, e.g. (1) landfarming for the microbial degradation of hazardous compounds, and (2) soil washing for scrubbing soils ex-situ to remove contaminants through particle size separation, coupled with innovative techniques to recycle and increase in value the contaminated sediments. The main objective of this section of Sediportsil project is to verify the quality of the material obtained by the sediment treatment in prototype. Moreover, the results will be used to evaluate the efficiency of treatment in prototype (soil washing) and the additional process (landfarming) applied to one fraction of treated sediment (silt < 75µm). The sediment classification will be use to demonstrate the efficiency of the treating processes on a sample of Port of Ravenna sediments, considering three kinds of process: 20
1)
soil washing and sorting in prototype on whole sediment to obtained 2 “clean” fractions (sand and silt)
2)
landfarming with microbial addition (inoculum) on silt fraction in order to obtained an additional reduction of pollutants.
3)
Plasma treatment (Action 4) on whole sediment and Protoype fractions to obtain Silicon and not hazardous wastes.
The Plasma treatment will be discussed separately, in a dedicated paper.
2.
METHODS AND MATERIALS
2.1
Sediment sampling
During February 2011, a sampling campaign was carried out and more than 30m3 of sediments were collected in port areas characterized by different level of pollution as suggested by previous studies (red, yellow and green, according to Italian regulation Dlgs 152/06, Annex 5, Table 1 limits). Briefly, for each class, around 10 m3 of dry sediment has been gathered through a seal bucket (each of this sample will be called hereafter TEST) coupled at a core sample for stratigraphic characterization. The sediments were collected, labelled and stored in order to carry out the characterization and tests (both laboratory and prototype).
2.2
Sediment characterization
Laboratory analyses [1-18] have been carried out according to D.Lgs.152/2006 (Part IV, Title V, attachment 5) of Italian Regulation, integrated with the “Handbook for movement of sea sediment (APAT-ICRAM, 2007 on behalf of the Ministry of the Environment). The classification of the treated sediments has been done considering: a. b. c. d. e.
Physical characterization, to evaluate the efficiency of sorting process Chemical characterization, to detect the chemical contents and distribution Microbiological characterization, to verify the reuse of materials Ecotoxicological characterization, to compare the quality of sediment and fractions Elemental characterization, to verify Silicon and other metal recovery
On the basis of the classification performed before the Prototype treatment, three difference sediments have been treated following the “colour” classification (RED, YELLOW and GREEN) and fraction classification, obtained during sorting in prototype: - >2 mm : shells and residual - 2 mm < x < 63 µm: sand - X< 63 µm: silt Moreover, a final characterization of treated sediment (after treatment characterization) has been finalized: 1) to assess the hydrocarbon distribution in sandy and silt fraction, carrying out analysis of total hydrocarbons in the two fractions, obtained after the treatment; 2) to evaluate the treatment effect on ecotoxicological response, performing bioassay also after the treatment, in order to select the best amending and/or chemical agent for the treatment; 21
3) to consider the microbiological content in the treated sediment (2 fractions) in order to verify the possible reuse of one or both unpolluted fractions; 4)
to detect the reduction in volume of final material, after the treatment. Finally, it has been verified also the quality of waste water, produced during the process in Prototype.
2.3
Soil-washing treatment through prototype
Chemical analysis and preliminary laboratory tests on sampled sediments were used to collect baseline data for the design and development of the sediment treatment prototype realized by DIEMME. The prototype was designed for grain size separation and progressive washing of Ravenna port sediment, meanwhile concentrating the contaminants into the finest fraction (Figure 1). The Ravenna sediments sample based on their contamination were originally subdivided into green, yellow and red classes (TESTs) and have been treated separately trough the prototype with 3 different cycles. Coarse and sandy fraction was recovered clean and not contaminated, the silt-clay finest fraction presented a high hydrocarbons concentration and was processed through landfarming. Wastewater did not present critical issues, except for chlorides level that resulted above the Italian Regulation limit.
Figure 1: Scheme of prototype pilot plant.
2.4
Landfarming application
Landfarming, also known as land treatment or land application, is an above-ground remediation technology for soils that reduces concentrations of petroleum constituents through biodegradation (EPA, 2004); selected bacterial strains that use organic contaminants as Carbon source reduce concentrations of petroleum constituents through biodegradation. The treatment has been carried out on 9 different samples (3 treatment cycles for 3 different pollution classes), in plastic boxes where the sieved and dry sediment has been inoculated at the beginning of experiment and manually mixed daily. Periodically (7, 15, 21, 51 and 86 days of treatment, Table 1), a subsample has been collected in order to assess the degradation and the nutrient contents. At step 4th a further sieving has been done in order to increment the oxygen distribution and to improve degradation rates. 22
Process step
Sampling date
Step 1 (T0) Step 2 (T1) Step 3 (T2) Step 4 (T3) Step 5 (T4) Step 6 (T5)
30/08/2011 06/09/2011 14/09/2011 20/09/2011 20/10/2011 24/11/2011
Process time (days) 0 7 15 21 51 86
Table 1: Landfaming process steps detail
Figure 2: Example of landfarming sample (Green TEST – replicate 1) at step 5
3. RESULTS AND DISCUSSION 3.1 Dredged sediments characterization Sediments from the Port of Ravenna were fully characterized, in accordance with the existing Ministerial Decree DM 471/99, to establish an accurate quantification of their different levels of pollution. As a consequence of this historical information, sediments have been subdivided in three different categories depending on their degree of contamination: Green (no polluted sediments), Yellow (mean polluted sediments) and Red (highly polluted sediments, mainly due to the high content of hydrocarbons). Comparing historical data and new ones, the classification has been confirmed even if in the “green” TEST, the hydrocarbons contents (58 mg kg-1 for total hydrocarbons and 0.15 mg kg-1 for benzo(ghi)perilene) slightly exceed the lower limit of Italian regulation (50 mg kg-1 and 0.1 mg kg-1, respectively). In this case, the sediment can not be classifiable as “not polluted”.
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Exceedances of lower limit (Table 1A):Benzo (g, h, i) perylene Total hydrocarbons C>12
Port of Ravenna Exceedances of lower limit (Table 1A):Arsenic Benzo (g, h, i) perylene, Chrysene, PCBs, C12 (it exceeds also the upper limit)
Si composition: 33.05 – 35.28% Exceedances of lower limit (Table 1A):Benz (a) pyrene, Benzo (g, h, i) perylene
Total hydrocarbons C>12
Si composition: 30.30 - 32.34 %
Si composition: 34.25 – 36.14 %
Figure 3: Sampling points and main results.
Composition data of heavy metals and hydrocarbons for each category measured in mg/kg on a dry basis is shown in Table 2: Cd
Ni
Pb
Cu
Zn
Hg
As
V
Cr tot
Cr VI
Hydroc. C>12
Hydroc. C
