REUSE OF CONSTRUCTION AND DEMOLITION WASTES (CDW). THE CASE OF SARDINIA ISLAND (ITALY

Transcription

1 REUSE OF CONSTRUCTION AND DEMOLITION WASTES (CDW). THE CASE OF SARDINIA ISLAND (ITALY G. MEI*, G. BALLETTO*, L. FRANCESCONI*, C. FURCAS*,S. NAITZA*, L. PANI*, N. TRULLI * * Department of Civil, Environmental Engineering and Architecture (DICAAR, University of Cagliari, Italy. SUMMARY: The CDWs (Construction and Demolition Wastes) are one of the most important and significant waste streams in Italy and in Europe. Their management and recycling is a major challenge for member states. The present work aims to define the management situation of CDW in Sardinia, in order to assess the economic and social perspectives that result from the reuse as secondary raw materials. A database, integrating data from a first phase of the research (Balletto et al, 2013), has been constructed to illustrate the situation of the CDW management in Sardinia in terms of production, typologies and costs. The information were carried out by different channels: first, we asked to fill out a question form from the operators of authorized recycling facilities in the region, and, after, we collected available information in the public offices. By means of question form, information about the types of equipment, the amount of inert produced in previous years, the quality of materials (the REC codes of their waste) and the output data (type of products sold, their final use, etc. ) in addition to the cost of disposal and sales prices have been collected. All of this information helped to define the pattern of CDW, from their production (restructuring, demolition etc.) until their processing and reuse. In particular, we focused our attention on the mineral part of CDW and it was possible to note that the majority of it is currently used, after treatment, as road foundations or as filling material, while the other uses, including the structural one, is virtually absent. This database has been integrated with the data of the natural aggregates quarries located in the region (PRAE - Regional Plan for Mining Activities - Region of Sardinia).We also compare the demand for aggregates of three municipalities of Sardinia with production of Recycled Aggregates. 1. INTRODUCTION Sustainable development and environmental protection are topics of great interest around the world in order to reduce the increasing consumption of energy and exploitation of non-renewable natural resources. Environmental issues related to the large amount of Construction and Demolition Wastes (CDW) require to seek innovative solutions for a more effective recycling of these materials from the point of view technical / technological and from that of the instruments planning and management of the territory. On the hand, the development of new technologies and new products to promote the reabsorption of these wastes as aggregates (AR) is in the field of construction both in alternate fields, on the other hand, however, the planning tools must

2 encourage their use through ad hoc actions such as certification and the incentive, economic or no. Recycle inert waste means reducing the indiscriminate use of non-renewable raw materials likely to decline more and more, to contain the high costs of disposal and to recover and reclaim landfills offering new spaces available for the community. Sustainable development is now essential for most of the European countries; in Denmark, the Netherlands, Belgium and Germany, for several years develop studies that have as their primary objective the recycling of building materials. The policies of recovery and reuse of these materials are now a central point for all those who work in the construction industry. In Italy, the construction industry produces more than 50 million tons of waste and residues, a huge amount of waste for disposal which can instead be transformed into an extraordinary reservoir of materials to be recycled, with obvious benefits for the environment and interesting employment opportunities. At present in our country there is an adequate "accounting" of inert waste, which constitute one of the main items of the national budget of the waste, but it is very difficult to carry out a census in recycling plants actually operating within the national territory. Then there is the problem of the strong cultural resistance due to the use of recycled material, since we tend to think of them as a material with characteristics and performance requirements lower than those traditionally used. The problem is accentuated inexistence of appropriate standards and guidelines designed to encourage both the use of recycled materials is the innovative use of large-scale, and the total absence of these items in the terms of reference for national construction and restoration of civil engineering works. Aggregates are mostly used in the construction industry, both in road and railway works is in the production of other high-quality materials such as concrete, asphalt or ready-made products. In order to meet the demand for this type of materials, products in the European Union every year about 2 billion cubic feet of aggregates (UEPG, 2012). This work aims to study the situation in the region Sardinia, where CDW represent approximately 1,127,644 tons in reference to the year 2008 (RAS, 2012). In fact, due to its particular condition of insularity, Sardinia region is forced to meet the demand for aggregates with their own raw materials, as the trans-regional import is not possible for economic reasons. Therefore, the Sardinia can be considered as a "closed basin", both as regards the supply of natural and recycled aggregates.(balletto et al 2013). 2. MATERIAL 2.1 Construction and demolition wastes The "waste from construction and demolition" or CDW (Construction and Demolition Wastes) are the waste corresponding to the macro item 17 of the EWC European Waste Catalogue, excluding hazardous waste and naturally occurring material from which the ERC ("land and stones other than those mentioned in "). These wastes are primarily derived from the construction, maintenance and renovation of the building works and the construction and maintenance of road and rail infrastructure. In Italy, the management of waste is governed by Legislative Decree no. 152/06 which inserts "waste resulting from the demolition, construction, and waste resulting from excavation activities..." on special waste category. Given their origin, these wastes are characterized by a rather heterogeneous composition: the fractions most relevant from the point of view of quantity are represented by cement, concrete, bricks and ceramics. These types of waste, although characterized by great potential for recovery and reuse, are still largely disposed of in landfills or even abandoned in illegal dumps. The European Union is committed to a number of actions with

3 the purpose of raising awareness among member states to adopt tools and initiatives to implement a proper policy for the management of such waste. Prevention, preparation for re-use (introduced by Directive 2008/98/CE), material recycling and recovery were identified as the most preferred options. The use of landfills is the last and least desirable option. At the end of the following contribution we intend to evaluate the stone component of the CDW, the one that is made up of cement, aggregates and concrete. The recycling of this fraction allows us to produce the so-called Recycled Aggregates which can be employed in the construction sector These applications are used in the field of civil engineering works on the ground (body found, environmental restoration, fillings and filled, for concrete with low resistance) and work in road and rail (substrates road, rail, airport and squares, civil and industrial foundation layers of the transport infrastructure, layered accessories with capillary function antifreeze, draining, etc..). The introduction of CE marking for construction materials and the publication of harmonized standards on aggregates have officially sanctioned the overcoming of the traditional distinction of aggregated according to their nature, imposing evaluate the material only for the performance characteristics of the same. The birth of the new product can reasonably be identified when the material is subject to certain quality standards (as defined by the designer or by specific rules) depending on the intended usage. Compliance with the standards must be guaranteed by a control of the whole process of recovery from waste management input, through the production process and the technology used, the requirements of the product. The path quality evaluation should analyze the final product from the technical point of view and from the point of view of the environment. The potential impact of recycled aggregates on the total demand for aggregates is about 40%. Factors that should / could encourage recycled aggregates compared to the natural ones are: lower price of natural materials replaced; high demand for materials with low performance (substrates, fills, enticements, recorded, etc.).; limitation of transport costs (which can be canceled in the case of the production in the pipeline). In Italy since 1997 is established the obligation to purchase products from recycled material: it states that public bodies and companies with a majority public capital should buy products made from recycled material not less than 30% of demand (40% for paper). In particular, for the building refers to the Circular 15 July 2005 n of the Ministry of Environment and Infrastructure, which defines the performance characteristics of recycled aggregates for embankments, layers of foundation, road foundations, asphalt and environmental recovery. 2.2 CDW Planning in Sardinia (Italy) The instrument analyzed in order to describe the situation of the management of CDW in Sardinia is the Regional Waste Plan Special approved December 21, 2012; the data from this instrument refer to the statement MUD (Model of the Environmental Declaration) of 2009 with 2008 data (Law 70/94) is an annual report of the waste produced, processed, transported or sent for disposal in the course of 'past year. The production of CDW in 2008 amounted to a total of kg, which account for 9% of the total regional production of hazardous waste and correspond to 670 kg per capita. It should be noted, however, how this data production can be considered only a part of CDW; this is just the amount that is declared by treatment plants. The production of CDW in Sardinia (per capita production of approximately 670 kg / inhabitant /

4 year) seems under evaluated as shown by comparison with the national average (close to 900 kg / inhabitant / year) and by comparison with the data obtained from data analysis of other territories in the national context. Tables 1 and 2 show the distribution of CDW in Sardinia and recovery rates. Table 1 - CDW Production in Sardinia Type Description Production CER "Waste mixed construction and kg demolition waste, other than those referred to in items , e CER "Mixture of concrete, bricks, tiles kg and ceramics other than those mentioned in CER iron and steel kg CER cement kg CER CER bituminous mixtures kg other than those mentioned in Table 2 - Recovery rate and objectives for CDW in Sardinia. objective 2015 objective 2020 Material recovery 53.00% 65.00% 70.00% Energy recovery 0.10% 0.00% 0.00% Treatment 46.70% 35.00% 30.00% Disposal 46.00% 3.METHODS The information collected in a database and processed on GIS support has been obtained through the following channels (Mei et al 2013): Analysis of materials by mean of the Special Waste Plan 2012; Census of treatment plants in Sardinia from Provincial Waste Management Interview managers and cataloging of the plants; Assessment of the needs of aggregates through the analysis of urban plans of several municipalities of Sardinia (a minor island, a coastal municipality and the capital city Cagliari) Plan for Extractive Activity of Sardinia for identifying natural quarries of inert

5 3.1 Cataloging of Inert Recycling Plants in Sardinia The CDW recycling plants have been identified through the analysis of information available by the provincial authorities. After that, we delivered a form to fill out by operators (fig.). The analysis of forms has allowed us to highlight the main features of the treatment plants in Sardinia and their location in the territory (fig 1). Fig.1, CDW Plants in Sardinia In particular we note: The most common type of plant is the jaw crushing; The material is visually checked before treatment in order to highlight the presence of improper materials; Reinforced concrete and concrete blocks are not separated from other types of material; The material produced is primarily intended for road foundations; The labor force present in individual plants is limited to 1-2 units. This information have been implemented in GIS support and allowed to develop some thematic maps, in particular in the following figures are shown the location of the plants in the territory of Sardinia and their relationship with the natural aggregates quarries. 3.2 Demand for aggregates The demand for aggregates of a given territory is intended mainly to private construction and public works, given that the construction industry is the largest field of application of the aggregates. The demand for aggregates usually comes from the construction industry, both in the residential and industrial, which can be both private and public initiative. The literature on the subject (Badino et al., 2006) identifies a number of approaches, among which you have chosen to adopt in this work the need assessment of aggregates in reference to the provisions of local planning instruments. This method is based in particular on the estimation of the possible consumption of minerals. Usually, the local urban plans are for a time period of 10 years. Therefore, the assessment of the need for inert in relation to local planning instruments is based

6 on the assumption that the predictions of the PUC (City Urban Planning) will be released during this time. In fact, this condition is not always true, and actions by the PUC may change or delay, and affect much longer periods of time. The evaluation of the needs of aggregates according to this methodology is derived from the planned volumes in the individual homogeneous urban areas (expressed in square meters), curtailed the already built-up areas, on the basis of their spatial indices (expressed in cubic meters / square meter). In the evaluation of the needs of aggregates were taken into consideration the following homogenous areas in which we expect the increased building activity: The "A" zone: Old Town; The "B" zone: Residential Completion; Area "C": residential expansion. The area "D": industrial, craft and commercial; The area "G" General Services; The area "S": Public Spaces. By correcting the volumes obtained with coefficients available in the Region of Sardinia, you get the quantity of materials required for the realization of the planned works. With this method, we calculated the requirements of aggregates for some municipalities of Sardinia, broadly diversified by location and growth trend. In particular, we have chosen the towns of Cagliari Carloforte and Tortoli. Cagliari is the most populous city of Sardinia, characterized by a compact and built a pole of attraction for the whole neighborhood; Carloforte is a small town located within a smaller island connected to Sardinia only via maritime transport, so it is a closed basin situation even more pronounced; Tortoli is a coastal town with a strong tourist and constant population growth, also located in a region of Sardinia, Ogliastra, only recently involved in works that are reducing the isolation. We then calculated the demand for materials for the renovation of the historic centers of Nuoro and Ogliastra Province characterized by depopulation where you are starting interest policies aimed at enhancement of historic centers as drivers of economic growth and demographic change. In this case the demand is calculated in by analysis of Metric calculations presented for obtaining funding for requalification in reference to LR 2) / The values obtained with the method of calculation of the needs expressed by the Region of Sardinia according to the method shows interesting quantities of sand (about cubic meters) and gravel (about cubic meters). The results for Cagliari, Carloforte e Tortolì are shown in the following tables. Table 1 - CDW Production in Sardinia Demand for aggregates (mc/years) Cagliari Carloforte Tortolì Construction Viability Construction Viability Construction Viability Zone A Zone B Zone C Zone Cf Zone D Zone F Zone G

7 S areas RESULTS AND DISCUSSION What emerged from this phase of the research, in reference to the entire territory of Sardinia can be summarized as follows. First, the analysis of the needs of aggregates confirmed the trend repeatedly reported the influence of the shape of the city on the same requirements. The geographic location of the plant in relation to municipalities chosen seems rather disorganized. In fact, while Cagliari you have at their disposal a number of plants from which to draw material, there is only one reference plant in Tortolì and Carloforte even no system but only a landfill. In the latter case, therefore, all the requirements of aggregates of this council can be satisfied only with the help of natural materials from the quarry located on the island. Even plants in the province of Nuoro and Ogliastra do not seem to be able to contribute to the strong requirements for the redevelopment of the historic centers of the territory. From this analysis, even if one considers only the needs of the city of Cagliari, the production of AR fails to reach Sardinia rates in line with those of green purchasing or with those of the objectives of the Regional Waste Plan Special. It should be emphasized, however, that it is important quantities that help to reduce the use of natural aggregates and the amount of CDW in temporary deposits even in illegal dumps. 5. CONCLUSIONS The estimates of the demand for aggregates applied to the case study highlighted the need to develop measures to promote the development of recycling and reuse of CDW in the construction industry. These estimates show large quantities of aggregates are needed to be found a short distance from the yards of use. The increasing difficulty of obtaining concessions for the extraction of aggregates and increased attention to environmental issues related to the mining activity itself (landscape impacts in particular) leads to a focus on use in construction of Recycled Aggregates which have already been established with regard to road works. The CE marking and optimization techniques to improve the quality of these products allow you to replace these aggregates natural products without compromising the quality of building. The technical component must be associated with the policy to promote the use of these products through the imposition of increasing percentages in the contract, in order to overcome the culture that continues to prefer the natural aggregate despite similar performance and a lower price. ACKNOWLEDGEMENTS This work was performed within the framework of the project called "The recovery of inert waste for the packaging of recycled aggregates for use in concrete. Experiments and applications in the provinces of Cagliari and Carbonia-Iglesias, "with the support of REGIONAL LAW August 7, 2007, No. 7:" PROMOTION OF SCIENTIFIC AND TECHNOLOGICAL INNOVATION IN SARDINIA. REFERENCES Badino V., Blengini G.A., and Garbarino E. (2006). Analisi tecnico economico ambientale

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