Showing papers by "Ligia Tiruta-Barna published in 2013"

An integrated “process modelling-life cycle assessment” tool for the assessment and design of water treatment processes

Abstract: Purpose The application of Life Cycle Assessment (LCA) to the design of water treatment plants is hampered by: (1) a large diversity of unit processes, (2) the high variability of the operation conditions in relation with the water quality input, and (3) the range of possible technical solutions to fulfil the treatment needs. For a consistent prospective assessment, the LCA should be based on the simulated functioning of the unit processes rather than on average data, as it is most often the case when no real data are available. Here, a novel, integrated and flexible process modelling-life cycle assessment (PM-LCA) tool for design and LCA of water treatment technologies is presented.

Emergy-based mid-point valuation of ecosystem goods and services for life cycle impact assessment

Abstract: Ecosystem goods and services (EGSs) are of crucial importance for the economic and social development of human communities. The well-established life cycle assessment (LCA) method is facing a number of challenging improvements to define new Characterization factors (CFs) for life cycle impact assessment (LCIA) of EGSs. Very recently, extensive work conducted under the UNEP/SETAC Life Cycle initiative has been completed with the goal of providing new LCIA methods and spatially differentiated mid-point CFs for land use and land use change impacts on biodiversity and ecosystem services. However, the implemented models do not enable one to assess the actual damage to ecosystem functionality, and thus the relationship among EGSs and related areas of protection (e.g. AoP of "Natural Resources") remains undefined. This paper aims at investigating the potential characterization ability of the Emergy method for LCIA of EGSs. The goal is to use the extensive libraries of Unit Emergy Values (UEVs) of primary services and resources as CFs for LCIA to evaluate the physical contribution of EGSs in supporting life cycle processes. Having its roots in thermodynamics and systems ecology, Emergy can appraise a larger and more diversified (than LCA) number of EGSs through a common physical denominator, i.e. the solar emjoule or seJ, which measures the solar energy embodied in natural products. Emergy thus has a typical Nature-oriented perspective, accounting for the available energy that is used up by the natural cycles, directly and indirectly, to generate biotic and abiotic resources. A library of selected UEVs (more than 100) for biophysical EGS valuation has been framed including values collected from the Emergy literature and formulated on the latest planetary baseline (i.e. 15.2E + 24 seJ/yr). Advantages and limitations for future application of these values toward an LCIA mid-point impact characterization of Emergy are discussed. UEVs may represent mid-point LCIA factors for ecological contribution analysis, enabling one to account for the memory of energy previously required to produce EGSs, which can be used as a proxy to assess the future environmental work necessary to regenerate the used EGSs. However, the added value of Emergy for LCA is still debated, mainly because of the low accuracy and unclear meaning of the UEVs in relation to the availability of resources. Therefore, Emergy can be conceived as a suitable physical measure complementary to the economic valuations and current "user-side" tools applied in LCA.

Accounting for the Emergy Value of Life Cycle Inventory Systems: Insights from Recent Methodological Advances

Abstract: Emergy, due to its unique ability to translate into a single metric the memory of the geobiosphere exergy (environmental work) supporting any (technological or natural) system, has the potential to offer a new perspective of environmental assessment to support decision-making. Previous work by a number of researchers has pointed out the expected advantages of taking a hybrid approach combining Emergy Evaluation (EME) and Life Cycle Assessment (LCA). In particular, emergy calculation using Life Cycle Inventory (LCI) databases and LCA matrix-based formulation is claimed to have the potential to increase the reliability of emergy-based evaluations and thereby the applicability of the emergy concept in environmental decision-making. The paper points out the main obstacles to overcome in order to reach this consistent integration, highlighting the progresses made so far in this direction, until the most recent practical and operational advancements.

Using graph search algorithms for a rigorous application of emergy algebra rules

Abstract: Emergy evaluation (EME) is an environmental assessment method which is gaining international recognition and has increasingly been applied during the last decade. Emergy represents the memory of the geobiosphere exergy (environmental work) – measured in solar emjoules (seJ) – that has been used in the past or accumulated over time to make a natural resource available. The rationale behind the concept of Emergy is the consideration that all different forms of energy can be sorted under a hierarchy and measured with the common metric of the seJ, which is then the yardstick through which all energy inputs and outputs can be compared with each other. For this reason EME is suggested to be a suitable method of environmental accounting for a wide set of natural resources, and can be used to define guidelines for sustainable consumption of resources. Despite those interesting features, EME is still affected by several drawbacks in its calculation procedures and in its general methodological background, which prevent it from being accepted by a wider community. The main operational hurdle lays in the set of mathematical rules (known as Emergy algebra rules) governing EME, which do not follow logic of conservation and make their automatic implementation very difficult. This work presents an open source code specifically created for allowing a rigorous Emergy calculation (complying with all the Emergy algebra rules). We modeled the Emergy values circulating in multi-component systems with an oriented graph, formalized the problem in a matrix-based structure and developed a variant of the well-known track summing algorithm to obtain the total Emergy flow associated with the investigated product. The calculation routine (written in C++) implements the Depth First Search (DFS) strategy for graph searches. The most important features of the calculation routine are: (1) its ability to read the input in matrix form without the need of drawing a graph; (2) its rigorous implementation of the Emergy rules; (3) its low running time, which makes the algorithm applicable to any system described at the level of detail nowadays made possible by the use of the available life cycle inventory (LCI) databases. A version of the Emergy calculation routine based on the DFS algorithm has been completed and is being tested on case studies involving matrices of thousands of rows and columns, describing real product production systems.

Assessing the potential environmental hazards of concrete made using recycled aggregates (RAs)

Abstract: This chapter starts with widely recommended and used methodologies for environmental assessment, with an overview of their application to construction materials. The concept of pollutant emission by leaching and its dependence on the materials involved is introduced, along with the parameters influencing the leaching process. The manner in which water contact with materials causes transfer, transport and dispersion of the contained contaminants is explained. Then the most relevant experimental tools dedicated to hazard identification and environmental performances are presented. These tools comprise laboratory leaching tests whose suitability for future standardisation in the field of construction materials is considered. Ecotoxicology tests could potentially be adapted to this standard testing method. The second part discusses recent research and discoveries concerning the leaching properties and potential hazards of materials of concern. The chemical behaviour of several pollutants in cement matrix is explained and examples of results obtained by leaching studies on concrete materials are discussed. Examples of studies on recycled aggregates (RA) from demolition as well as new concrete materials containing these wastes are also presented.