Promoting ecological sustainable planning for natural stone quarrying. The case of the Orosei Marble Producing Area in Eastern Sardinia

This paper presents an analysis of the main environmental impact factors (noise, vibration, fumes, dust, vehicle traffic) associated with marble quarrying and processing in the Orosei industrial area and their effects. Solutions are also proposed to prevent, mitigate and, where possible, eliminate the impact on the environment. Using three-dimensional topographic models, the authors simulated quarry and industrial processing development, with projections over the next 10, 30 and 50 years. The aim of these simulations was to establish land management planning guidelines for the optimal and environmentally sustainable development of the Orosei Marble industrial area. Lastly, careful quarry development planning is important both for enhancing LCA and for improving production processes through sustainable technologies that yield green label products meeting environmental performance standards.     

Self-potential monitoring of a crude oil-contaminated site (Trecate,Italy)

We present a multidisciplinary approach for characterization of a crude oil-contaminated site (Trecate, Italy), integrating geophysical data, such as subsoil electrical potential (in millivolts) and electrical resistivity (in ohm meters) distribution, with hydrogeological and bio-chemical data. Self-potential measurements have been evaluated together with active geoelectrical measurements and hydrological information, to provide spatial and temporal information about the self-potential sources and their possible correlations with the contamination state of the subsoil. Three self-potential surveys (March 2010, October 2010, and March 2011) were conducted at the site, both in the contaminated and uncontaminated regions. The obtained self-potential maps show large time-lapse differences in correspondence of the contaminated area, with positive electrical potential values (up to 50 mV) in spring surveys and an electrical potential dipolar distribution in October (2010) survey (amplitude from ?15 to 25 mV). To understand the origin of the measured self-potential signals, a model using vertical dipolar electrical sources was built, taking into account the electrical resistivity distribution deduced from electrical resistivity tomography. The self-potential source identification allows the Trecate contamination state to be better delineated. In particular, two self-potential contributions are superimposed: the electrokinetic mechanism is predominant in spring, while the redox mechanism represents the most important contribution in autumn.     

An enhanced sustainable approach for design and manufacturing with an application to fuselages for mono-seat civil sailplanes

Abstract

A number of tools and software systems have been developed in order to reduce the time for the design and manufacturing of industrial products. Nowadays, virtual modelling by Computer Aided Design (CAD) systems and process simulation by the application of Finite Element Method (FEM) software is a standard routine in order to compress product design activities and to achieve the optimal solution before producing any real components. These developments provided not only a reduction in the time to market but a higher complexity of the project and an improved quality of the industrial products. With the aim to further improve the sustainability of this activity, the implementation of a tool that adds automatic operations into the design activity is demonstrated. This software can interact with any CAD and helps designers when the object dimension and shape can be affected by limits and constraints deriving from different features and targets, such as the spatial collocation of the component and the interaction with other limiting items, for examples the material and the manufacturing issues. The concept was developed into the software SFIDA (Sailplane Fuselage Integrated Design Application) that is a first attempt to automatically manage multiple relations and optimise their combination.     

Degradation of para-hydroxybenzoic acid by means of mixed microbial cultures

Olive mill wastewater contains some phenolic compounds that cause antibacterial activity of a kind that prevents biological treatment without previous dilution. Among these phenolic compounds, p-hydroxybenzoic acid (PHB) is considered to be one of the most representative. This work examines the biodegradation of PHB by aerobic microbial mixed cultures previously acclimatized to glucose, which was used as an easily biodegradable model compound. Microbial growth runs were carried out in a batch reactor in the PHB concentration range of 200-1000 mg/L. In all the runs the PHB proved to be completely degradable. The specific growth rates obtained were in the range of 0.16-0.35 l/h. Experimental runs showed that the functional relationship between the specific growth rate and PHB concentration was that proposed by Monod. The kinetic constants of the Monod equation (mu(max) and K(S)) and biomass yield coefficient (Y) were determined experimentally. With the parameter values thus obtained, a mathematical model that also takes account of the duration of the lag phase was employed to describe both the microbial growth and the consumption of PHB. The concentration values of the model fit well with the data obtained experimentally.     

From landfill to water,land and life: The creation of the Centre for stone materials aimed at secondary processing

This paper focuses on the creation of a Centre for the recycling of stone materials. The Centre will be able to offer a range of activities amongst which is the improvement of the production chain of the Orosei Marble district in Sardinia, Italy. Several companies operate within the marble producing area, specializing in both quarrying and stone processing. They have formed a Consortium in order to rehabilitate an area of more than 17 ha. The restoration will be carried out through an environmentally sustainable procedure. The area was previously used as a landfill for waste deriving from marble quarrying and processing. At that time unshaped blocks of various sizes (which are unsuitable to block-cutter sawing), waste deriving from both block sawing and slab/strip cutting (such as broken slabs, strips, tiles) and microfine dust from filter presses of water treatment plants were representing an environmental problem. The local administration was struggling to find new areas which could be used for landfills, resulting in an additional cost for the landfill, ultimately affecting the variable production costs. The project involves the building of a venue to be used for temporary storage, treatment of wastes produced by both quarrying and primary processing, in order to make them suitable as secondary raw materials. The project also deals with the catch basin hydrology of the area involved in the project, the building of a multifunctional centre, the landscaping and other environmental features such as vehicle traffic and slopes greening.     

CO2 capture from combined cycles integrated with Molten Carbonate Fuel Cells

In this paper Molten Carbonate Fuel Cells (MCFCs) are considered for their potential application in carbon dioxide separation when integrated into natural gas fired combined cycles. The MCFC performs on the anode side an electrochemical oxidation of natural gas by means of CO₃^2? ions which, as far as carbon capture is concerned, results in a twofold advantage: the cell removes CO₂ fed at the cathode to promote carbonate ion transport across the electrolyte and any dilution of the oxidized products is avoided.The MCFC can be “retrofitted” into a combined cycle, giving the opportunity to remove most of the CO₂ contained in the gas turbine exhaust gases before they enter the heat recovery steam generator (HRSG), and allowing to exploit the heat recovery steam cycle in an efficient “hybrid” fuel cell + steam turbine configuration. The carbon dioxide can be easily recovered from the cell anode exhaust after combustion with pure oxygen (supplied by an air separation unit) of the residual fuel, cooling of the combustion products in the HRSG and water separation. The resulting power cycle has the potential to keep the overall cycle electrical efficiency approximately unchanged with respect to the original combined cycle, while separating 80% of the CO₂ otherwise vented and limiting the size of the fuel cell, which contributes to about 17% of the total power output so that most of the power capacity relies on conventional low cost turbo-machinery. The calculated specific energy for CO₂ avoided is about 4 times lower than average values for conventional post-combustion capture technology. A sensitivity analysis shows that positive results hold also changing significantly a number of MCFC and plant design parameters.