Dr Alba Bala, head of the Waste Management line of research:

"We develop methodology and applications for better waste management. We foster an objective assessment of management options, looking for areas of improvement and aiding communication."


Our main ally in this line of research is Ecoembes. We have carried out a number of projects together as part of the Observatorio Punto Verde, which promotes Life Cycle Assessment for packaging. The Sociedade Ponto Verde of Portugal is also a member.

As members of the International Expert Group on Life Cycle Assessment for Integrated Waste Management, we keep up to date with all the latest advances in the field.

Key papers

Bozhikaliev, V., Sazdovski I., Adler, J., Markovska, N. (2019)

Bioenergy villages can be defined as villages, municipalities, settlements or communities, which produce and use most of their energy from local bioenergy and other renewable energy sources. A bioenergy village approach has not been applied in Macedonia yet, and it is at a nascent stage of implementation in other South-Eastern European countries. This work aims to integrate a techno-economic, social and environmental assessment and an implementation strategy into a bioenergy village concept, which is not often seen in works dedicated to bioenergy villages and biomass based heating systems. The assessment was conducted by means of energy audit and project-related tools, whilst the strategy was composed by bioenergy working group meetings. Results show that a biomass based district heating system is a more attractive solution for heating several public buildings instead of a fossil fuelled system, with numerous associated benefits. Such concepts can be replicated with variety of renewables, thus contributing to sustainable development pathways of small communities.

The aviation industry generates a significant amount of comingle waste. Nowadays, companies are making efforts to enhance waste management and reduce waste generation. In order to improve present practices and implement a proper waste management system, the quantities, materials, and typology of waste generated need to be studied. A total of 145 airplanes were analysed. We differentiated 5 strips of duration and identified 4 different generation sources within the cabin associated to the business and tourist passenger classes. We classified and characterized the waste into 20 different materials. Results provide a detailed, representative and adapted study of the catering waste generated in the aviation industry. The characterization, which allows distinguishing between manipulated and unmanipulated materials, aims at providing useful information to reduce the generation of waste. The analysis performed in the present study shows that the flying distance increases the waste generation, as more food is served. It also shows that organic matter, paper/cardboard and packaging are the dominant materials in the waste generated in flights. The results of the characterizations obtained allow making some recommendations. The use of bi-compartmentalized waste trolleys to separate on-board recyclable materials from the rest is desirable to obtain a clean recoverable waste stream. Supressing unpopular food from menus, identified analysing the leftovers, could also reduce the amount of waste generated. (This characterization study is part of the European project LIFE?+?Zero Cabin Waste.). Changes in the CE 1069/2009 regulation would allow more waste to be recycled instead of landfilled. Ultimately, the information obtained from this study will be used to design a more sustainable waste management system.

The aim of this article is to present a circular economy case study and investigate and discuss effects of end-of-life (EoL) allocation and crediting strategies on the results of this case study. In the case study, replacement of eucalyptus wood sheets, which are used to separate loaded pallets to prevent damaging each other during top storage in the company, by plastic compound alternatives composed of virgin PP, recycled PP and mineral fillers, is studied. When their life time is over, plastic compound sheets are sent to be recycled in the recycling facilities of the company. While performing this comparative LCA, a methodological discussion on how to credit the system in open-loop (OL) and close-loop (CL) recycling is performed. The use of Q factors (quality factors), instead of 1:1 substitution of virgin materials by recycled ones, is recommended and how to define these Q factors is discussed. The use of Q factors based on the mechanical properties of virgin and recycled materials, which is flexural modulus in this case, is
recommended. Finally, a formula for the calculation of the Q factor of the compound material leaving the CL recycling after several recycling cycles, is proposed. Results show that, for this case study, plastic compound sheets are environmentally better alternative than eucalyptus wood sheets for most of the environmental impact categories valuated due to the following reasons: higher number of uses, lower weight, use of recycled PP and mineral fillers, and longer lifetime. However, in two impact categories (resource depletion water and resource depletion mineral, fossils and renewables) eucalyptus wood sheets are found to have slightly better results. For the rest of the impact categories, the difference in the results are so high that different crediting methods do not affect the results in this case; however, they may in others. Among the scenarios evaluated OL recycling with market mix substitution is found to provide the highest impacts.

The use of industrial solid wastes with a high content of SiO2 and Al2O3, called “precursors”, is often studied in the construction industry when combined with NaOH as “activator”. The precursor and activator system is generally proposed as a binder material with similar characteristics to Portland cement. In this work, we technically and environmentally evaluated such a system elaborated with an industrial waste: coal ash with caustic soda in solid state. This product, mixed with the soil, acts as a stabilizer to increase the capacity of load support, allowing the improvement of the conditions of performance in low volume traffic roads. An experimental design applied to the stabilizing product showed the incidence of different factors on the load carrying capacity response: packaging material, type of seal, baling moisture and storage humidity. The application of the stabilizer product was found to increase the resistance of the ground over a 500%. Finally, the environmental aspects were evaluated through a simplified Life Cycle Assessment methodology (LCA), the scope of the study was restricted to cradle to gate, collecting data up to the packaged stabilizing product. The results showed that the highest impacts were caused, for most impact categories, by NaOH production, and transport was relevant as well.

The great concern regarding food loss (FL) has been studied previously, but in an isolated way, disregarding interdependencies with other areas. This paper aims to go a step further by proposing a new procedure to assess different waste management alternatives based on the nexus approach by means of an integrated Water-Energy-Food-Climate Nexus Index (WEFCNI). The environmental profile of the waste management techniques is determined using Life Cycle Assessment (LCA) which, in combination with Linear Programming (LP), explores the optimal aggregation of weighting factors that lead to an aggregated nexus index. The management of residues from the anchovy canning industry in Cantabria (Spain) has been used as a case study, considering the three current applied alternatives: (i) valorisation of FL as animal feed in aquaculture (food waste-to-food approach), (ii) incineration of FL with energy recovery, and (iii) landfilling with biogas recovery. The last two considered the use of energy recovered to produce a new aquaculture product (food waste-to-energy-to-food scenarios). The results indicate that incineration is the best performing scenario when the nutritional energy provided by the valorisation alternative is not high enough and the valorisation technology presents the highest water consumption. Therefore, a minimisation in the consumption of natural resources is suggested in order to improve the application of circular economy within the sector. The use of the nexus index as an environmental management tool is extendable to any food system with the aim of facilitating the decision-making process in the development of more sustainable products.

Key projects

Tackling International airline catering waste by demonstrating integral and safe recollection, separation & treatment (01/09/2016-31/12/2019). LIFE Zero Cabin Waste tiene como objetivo crear un modelo integrado para reducir, reutilizar y reciclar los residuos generados en los aviones (incluida la recuperación de energía) y establecer la base para que otras aerolíneas puedan aplicar este enfoque.

Product Environmental Footprint – pilot project on wine (01/06/2014- 01/06/2016). El objetivo del proyecto es la participación en los proyectos piloto organizados por la Dirección General de Medio Ambiente de la Comisión Europea para desarrollar Reglas de Categoría de Huella Ambiental de Producto y canales de comunicación para comunicar la huella ambiental del vino. La iniciativa consiste en una prueba piloto de las Reglas de Categoría de Producto en coordinación con bodegas de España, Francia e Italia.

El objetivo del Estudio ARIADNA es analizar la sostenibilidad ambiental, social y económica de la implantación en España (y en Cataluña, como ejemplo de Comunidad Autónoma) de un Sistema de Depósito, Devolución y Retorno (SDDR) obligatorio. El estudio no analiza los dos sistemas de forma aislada, sino que compara el actual Sistema Colectivo de Responsabilidad Ampliada del Productor (SCRAP) con una situación hipotética en la que convivirían los dos sistemas (SCRAP y SDDR). Se trata del estudio más completo sobre SDDR llevado a cabo hasta la fecha en Europa.

El objetivo del Estudio ARIADNA es analizar la sostenibilidad ambiental, social y económica de la implantación en España (y en Cataluña, como ejemplo de Comunidad Autónoma) de un Sistema de Depósito, Devolución y Retorno (SDDR) obligatorio. El estudio no analiza los dos sistemas de forma aislada, sino que compara el actual Sistema Colectivo de Responsabilidad Ampliada del Productor (SCRAP) con una situación hipotética en la que convivirían los dos sistemas (SCRAP y SDDR). Se trata del estudio más completo sobre SDDR llevado a cabo hasta la fecha en Europa.

El objetivo del proyecto FENIX es contribuir a mejorar la sostenibilidad en la gestión de residuos de envases, de acuerdo con los principios de la política europea en materia de gestión de residuos. El principal resultado del proyecto es una herramienta de software basada en la metodología ACV, flexible y fácil de usar. La herramienta de software permite comparar y analizar diferentes opciones para la gestión de residuos de envases con el fin de ayudar en la toma de decisiones de las administraciones públicas. Además, la herramienta tiene en cuenta los aspectos sociales y económicos más relevantes de la gestión de residuos.

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UNESCO Chair in Life Cycle and
Climate Change ESCI-UPF

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