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To facilitate the transition from a linear to a circular economy there is a need to develop digital tools that can provide comprehensive and useful data to enhance repair, remanufacturing, reuse, and recycling. This paper explains the typology of information key for such end, it discusses the current limitations and difficulties to implement methods in a digital platform, and a description of already existing digital solutions that will be further improved in the context of the DigiPrime project. A preliminary analysis of the availability and accessibility of information about electronics is required before the definition of a digital tool to support circular economy. First, the paper discusses the need of ‘digitalized’ end ‘standardized’ information of electronics to promote circular strategies. Then, diverse digitalization approaches by several teams of the Digiprime project are detailed. The paper concludes with a description of the next steps needed to align the diverse digitalization approaches and its potential contribution to improve the electronics sector.

The history of tourism in Malta goes back 60 years. While widely hailed for its economic contribution, very little reference is made to the waste externalities that riddle the industry. In islands like Malta, the impacts of waste generation are more pronounced particularly due to the size of the country and its population density. Furthermore, waste originating from the hospitality establishments is, in its majority, landfilled. Five-star hotels have been established to generate more waste than hotels in lower star categories. Focusing on an established five-star hotel, this research provides a comprehensive case-study that utilises a mixed methodology approach which supplies quantitative figures of waste generated in the a-la-carte, buffet restaurants and residents’ rooms, together with qualitative methods to furnish information and insights about waste generation and reduction initiatives. Results point to the pervasive problem of plastic and single-use items. In one week, 692.5 kg of waste is generated in the residents’ rooms, 50.3 per cent of which consists of plastic. The impact of single-use items is exposed by the difference in the ‘other’ fraction which reaches 0.05 kg/person, a stark contrast to the remaining fractions which reach 0.01 kg/person. Food waste is an aspect of the hospitality industry that cannot be side-lined. Plate-waste, measured in a month-long audit performed at the a-la-carte restaurant, reaches an average of 0.21 and 0.16 kg/person at lunch and dinner respectively. The buffet dinner exposes greater wastage with 0.48 kg/person. Preparation waste reached 0.08 kg/person. The relationship between portion sizes and food waste is exposed when the removal of a side plate decreases waste generation from 0.059 kg/person to 0.043 kg/person.

Social and spatial segregation structures in Latin America are perceived as processes for the selective concentration of social or demographic groups in geographic sectors of the city. This voluntary or forced segregation creates poor, wealthy, and marginal areas, leading to the territory’s marginalization and fragmentation, destroying the symbolic and territorial urban continuity. To understand the behavior of waste pickers in a Mexican city, we sought to know the conditions of the informal collection activity in eight Latin American countries with similar conditions. Therefore, the goal was to carry out a bibliographic evaluation that included the environmental contribution of waste pickers, their organizations, and their link with urban metabolism. The tasks performed by informal waste pickers in the cities of the eight selected Latin American countries, their organizations, and their way of working were studied. Their role in reducing environmental impact and improving the quality of life of city dwellers was evaluated. Web sites, web searches, and face-to-face meetings created electronic communication channels with this community were analyzed. In some cases, they are well organized and become microentrepreneurs with salary, social security, and economical insurance by starting an ecological business. In contrast, marginal groups seeking economic support collect, separate, sort, and group recoverable waste daily and sell it at waste distribution points. This link in the urban metabolism reintroduces valuable solid waste into the production chain. In addition, materials with commercial value, such as metals, plastics, paper, cardboard, and wood, can re-enter the production chain as secondary materials for industry. Thus, a collective of well-organized waste pickers contributes to the city’s sustainability and provides better living conditions for the waste pickers. In Mexico, there is a lack of official information regarding the number of waste pickers, organizations, activities, and their environmental contribution. Therefore, a directory with that information is highly relevant to designing public policies to recognize the essential contributions of this sector.

Unidad de excelencia María de Maeztu CEX2019-000940-M The metabolism of a building can be connected to a rooftop greenhouse, exchanging energy, water and CO2 flows, therefore reducing emissions and recycling cultivation inputs. However, integrating a rooftop greenhouse onto a building requires the application of stringent safety codes (e.g., fire, seismic codes), to strengthen and secure the structure with safety elements such as thick steel pillars or fireproof covering materials. These elements can shade the vegetation or reduce solar radiation entering the rooftop greenhouse. Nevertheless, application of additional LED light can help to overcome this constraint. The present study evaluated supplemental LED light application in an integrated rooftop greenhouse (i-RTG) at the ICTA-UAB research institute, located in Barcelona (Spain), for tomato cultivation (Solanum lycopersicum cv. Siranzo). The experiment explored the effects of three LED lighting treatments and a control cultivated under natural light only (CK). Applied treatments, added to natural sunlight, were: red and blue (RB), red and blue + far-red (FR) for the whole day, and red and blue + far-red at the end-of-day (EOD), each for 16 h d−1 (8 a.m.-12 a.m.) with an intensity of 170 µmol m−2 s−1. The results indicate that LED light increased the overall yield by 17% compared with CK plants. In particular, CK tomatoes were 9.3% lighter and 7.2% fewer as compared with tomatoes grown under LED treatments. Fruit ripening was also affected, with an increase of 35% red proximal fruit in LED-treated plants. In conclusion, LED light seems to positively affect the development and growth of tomatoes in building integrated agriculture in the Mediterranean area.

Unidad de excelencia María de Maeztu CEX2019-000940-M Altres ajuts: GROOF project (UE. Interreg NWE 474, 2017-2021) With the overall aim to design successful implementation strategies of food-energy-water production systems on urban roofs, we propose an integrated process that includes participatory processes and a multi-dimensional sustainability assessment of environmental, social and economic indicators. The proposed framework was applied to a typical housing estate in the Metropolitan Area of Barcelona made up of 201 buildings and 13,466 inhabitants and characterized by a high share of low-income families. We assess several future scenarios of joint electricity production (photovoltaic panels), vegetable production (through open-air farming and greenhouses), green roof implementation and rainwater harvesting and rank them according to non-participatory and participatory approaches. In general, there was a tendency for residents to choose strategies providing energy and water rather than the food production potential of rooftops. However, the environmental assessment indicated that the least impacting alternatives from a life cycle approach were those promoting vegetable production, meeting 42 to 56% of the residents' fresh produce demand and reducing environmental impacts by 24 to 37 kg CO 2eq m −2 of rooftop/year. Hence, we found that residents were mainly concerned with energy expenses and not so much with food insecurity, social cohesion or the impacts of long-distance supply chains. Our assessment supports urban sustainability and helps identify and breach the gap between scientific and user preferences in urban environmental proposals by informing and educating residents through a participatory integrated assessment.

Unidad de excelencia María de Maeztu MdM-2015-0552 Altres ajuts: Beatriu de Pinós 2016 BP 00132 Cities are becoming one of the greatest generators of waste and thus a potential source of secondary materials. One of the most attractive waste streams in cities is waste electrical and electronic equipment (WEEE) as they contain many valuable metals, mainly in the printed circuit board (PCB), with a high risk of a disruption in their supply. Many of the PCBs contained in small WEEE are separated by destructive operations, as the economic feasibility of their separation using non-destructive operations remains unclear. This paper examines the feasibility of separating the PCB and the permanent magnets (PMs) contained in hard disk drives (HDD) using non-destructive operations. The economic cost of separating these parts is evaluated by the disassembly sequences, the disassembly schemes, and using the 'ease of Disassembly Metric' (eDiM). In HDD, the economic cost for the non-destructive separation of the PCB is €0.05 while the cost to harvest the PCB as well as the PMs is €0.39. In both cases, such cost is well below the estimated economic value of the gold, silver, and palladium contained in the PCB (€0.85). As a result, the paper concludes that the separation of the PCB and the PMs of HDDs is economically profitable. Measures for promoting the non-destructive separation of the PCBs and the PM of HDDs should be further promoted, as they could help improve the supply of secondary raw materials.

The burning of fossil fuels is an unsustainable activity, which is leading to an increase in greenhouse gases (GHGs) emissions and related global warming. Among sustainable energy sources, microalgae represent a promising alternative to fossil fuel and contribute to the achievement of important Sustainable Development Goals (SDGs). In particular, the potential contribution of marine microalgae to sustainable development is large as, among other benefits, they represent a carbon negative energy source and may be applied in many coastal areas around the world. Despite this, significant economic and technological improvements are needed in order to make microalgae biofuels viable on a large scale. This review aims to explore how and to what extent third-generation biofuels (marine microalgae, but also the latest advances in freshwater microalgae) can benefit the realization of these SDGs. From this study we concluded that the production of large-scale marine microalgae biofuels is not yet feasible from the economic perspective at a large scale. However, the cultivation of microalgae in seawater holds great potential for increasing the small to medium viability of this biofuel source. The possibilities for improvement along with the contributions to sustainable development lay the groundwork for continuing to study and apply the potential of sustainable production of microalgae bioenergy.

The industrial symbiosis in eco-industrial parks requires intense broker involvement to be implemented. However, market changes and technological advancement could undermine the level of symbiosis during operations. In this research, the existing symbiosis indicators were identified and classified using a systematic literature review. The results demonstrated the necessity to achieve indicators sufficiently simple that brokers are enabled in confronting the monitoring and promotion of symbiosis. In this paper, an industrial symbiosis indicator is introduced that detects the variation of symbiosis over time and that provides a dynamic perspective of the eco-industrial parks. This indicator can be used in the underpinning of decisions and the provision of continuous improvement. It was evaluated in several theoretical scenarios created from real data. The three scenarios are: absence of symbiosis, presence of symbiosis, and perfect symbiosis. The results demonstrate consistency between the values of the indicator and changes in the scenarios. The industrial symbiosis indicator proposed was able to detect variations in symbiosis with simple measures, and could support managers in encouraging companies to actively engage in effort for more advanced levels of symbiosis. The concept of “environment impact momentum”, proposed and applied in this research, is a theoretical construct that could support a new class of indicators capable of identifying the dynamic behavior of eco-industrial parks.

For many companies, the greenhouse gas (GHG) emissions associated with their purchased and consumed electricity form one of the largest contributions to the GHG emissions that result from their activities. Currently, hourly variations in electricity grid emissions are not considered by standard GHG accounting protocols, which apply a national grid emission factor (EF), potentially resulting in erred estimates for the GHG emissions. In this study, a method is developed that calculates GHG emissions based on real-time data, and it is shown that the use of hourly electricity grid EFs can significantly improve the accuracy of the GHG emissions that are attributed to the purchased and consumed electricity of a company. A model analysis for the electricity delivered to the Spanish grid in 2012 reveals that, for companies operating during the day, GHG emissions calculated by the real-time method are estimated to be up to 5% higher (and in some special cases up to 9% higher) than the emissions calculated by the conventional method in which a national grid EF is applied, whereas for companies operating during nightly hours, GHG emissions are estimated to be as low as 3% below the GHG emissions determined by the conventional method. A significant error can therefore occur in the organizational carbon footprint (CF) of a company and, consequently, also in the product CF. It is recommended that hourly EFs be developed for other countries and power grids

In this paper, the material and spatial characterization of the flows within a municipal solid waste (MSW) management system are combined through a Network-Based Spatial Material Flow Analysis. Using this information, two core indicators are developed for the bio-waste fraction, the Net Recovery Index (NRI) and the Transport Intensity Index (TII), which are aimed at assessing progress towards policy-related sustainable MSW management strategies and objectives. The NRI approaches the capacity of a MSW management system for converting waste into resources through a systematic metabolic approach, whereas the TII addresses efficiency in terms of the transport requirements to manage a specific waste flow throughout the entire MSW management life cycle. Therefore, both indicators could be useful in assessing key MSW management policy strategies, such as the consecution of higher recycling levels (sustainability principle) or the minimization of transport by locating treatment facilities closer to generation sources (proximity principle). To apply this methodological approach, the bio-waste management system of the region of Catalonia (Spain) has been chosen as a case study. Results show the adequacy of both indicators for identifying those points within the system with higher capacity to compromise its environmental, economic and social performance and therefore establishing clear targets for policy prioritization. Moreover, this methodological approach permits scenario building, which could be useful in assessing the outcomes of hypothetical scenarios, thus proving its adequacy for strategic planning.

Summary We used a thermodynamic framework to characterize the resource consumption of the construction sector in 2001 in Catalonia, the northeast region of Spain. The analysis was done with a cradle-to-product life cycle approach using material flow analysis (MFA) and exergy accounting methodologies to quantify the total material and energy inputs in the sector. The aim was to identify the limitations of resource metabolism in the sector and to pinpoint the opportunities for improved material selection criteria, processing, reuse, and recycling for sustainable resource use. The results obtained from MFA showed that nonrenewables such as minerals and natural rocks, cement and derivatives, ceramics, glass, metals, plastics, paints and other chemicals, electric and lighting products, and bituminous mix products accounted for more than 98% of the input materials in the construction sector. The exergy analysis quantified a total 113.1 petajoules (PJ) of exergy inputs in the sector; utilities accounted for 57% of this exergy. Besides exergy inputs, a total of 6.85 million metric tons of construction and demolition waste was generated in 2001. With a recycling rate of 6.5%, the sector recovered 1.3 PJ of exergy. If the sector were able to recycle 80% of construction and demolition waste, then exergy recovery would be 10.3 PJ. Hence the results of this analysis indicate that improvements are required in manufacturing processes and recycling activities, especially of energy-intensive materials, in order to reduce the inputs of utilities and the extraction of primary materials from the environment.

This study is a quantitative description of Brazil's copper life cycle, comprising mining, refining, manufacturing, use and waste generation in the year 2005. A substance flow analysis is presented and the results are compared with existing values for other countries and economic regions (Europe, Asia, Latin America, and Africa). The results show that Brazil is a net importer of copper both in concentrate and in the form of finished goods (total net weight 64 kt). Internal copper consumption is 1.44 kg per inhabitant per year and 0.52 kg/inhab/year is accumulated in the form of stock. Otherwise, the amount of waste generated (1.4 t/inhab/year) is close to that generated in Europe (1.9 t/inhab/year). The copper distribution profile in waste flow is characterized by similar values for waste flow from construction and demolition (27.8%) and from electrical and electronic equipments (27.7%), whilst municipal solid waste and non-dangerous and industrial waste present 19.7% and 13.2%, respectively. Waste from electrical and electronic equipment and motor vehicles sent to scrap, in spite of representing just 1% of all waste in terms of mass, contain almost 38% of all residual copper (28% and 10%, respectively). Brazil presents a secondary copper-recycling rate of around 25%, differing from that of other developing countries because it imports little scrap copper and releases 142 kt into the biosphere (0.75 kg/inhab). We make the case that Brazil's government can feasibly encourage reductions in demand for this metal while increasing copper recycling rates through a two-edged strategy based on education and public awareness on the one hand – making a case for the unsustainability of current copper production and consumption models – and on the other, implementing economic tools to transfer costs of post-use recovery to manufacturers and consumers.

Material Flow Analysis (MFA) and Life Cycle Assessment (LCA) are widely employed in the study of topics related to industrial ecology. However, unlike this study, they are normally used separately rather than jointly. Educational institutions are among the most deeply rooted services in society, producing knowledge, research and culture. This paper reports on a case study conducted in the region of Catalonia, Spain, to evaluate the metabolism of the Autonomous University of Barcelona (UAB) based on a combined MFA and LCA approach on two levels: macro-level analysis using MFA, and micro-level analysis using LCA. The MFA results indicated that energy consumption represents more than 50.00% of all inputs, and its associated indirect flows are highly relevant for UAB's overall metabolism, accounting for 69.30% of all energy inputs. As for the LCA results, the ReCiPe2008 method was adopted and 92.00% of all normalized impacts were related to the category of Climate Change Potential (CCP), also attributed mainly to energy consumption. Thus, both MFA and LCA methodologies indicated energy consumption is the main hotspot. The results of MFA indicators, energy and water flows were compared with earlier literature, revealing a clear tendency for industrial areas in Catalonia to show higher results than service polygons, as an effect of population density. Finally, the newly erected building of the Institute of Environmental Science and Technology and the Catalan Institute of Paleontology (ICTA-ICP) is described as an innovative alternative to promote environmental sustainability at universities that focus on energy and water conservation and CCP impacts reduction.

Used cooking oil (UCO) is a domestic waste generated daily by food industries, restaurants, and households. It is estimated that in Europe 5 kg of UCO are generated per inhabitant, totalling 2.5 million metric tons per year. Recovering UCO for the production of biodiesel offers a way of minimizing and avoiding this waste and related pollution. An exergy analysis of the integrated waste management (IWM) scheme for UCO is used to evaluate such a possibility by accounting for inputs and outputs in each stage, calculating the exergy loss and the resource input and quantifying the possible improvements. The IWM includes the collection, pretreatment, and delivery of UCO and the production of biodiesel. The results show that the greatest exergy loss occurs during the transport stages (57%). Such exergy loss can be minimized to 20% by exploiting the full capacity of collecting vans and using biodiesel in the transport stages. Further, the cumulative exergy consumption helps study how the exergy consumption of biodiesel can be further reduced by using methanol obtained from biogas in the transesterification stage. Finally, the paper discusses how increasing the collection of UCO helps minimize uncontrolled used oil disposal and consequently provides a sustainable process for biodiesel production.

This study presents the application of exergy analysis in assessing how effectively resources are utilised in construction material manufacturing. The role of exergy is discussed from several key perspectives such as quality, energy conservation and process improvement potentials. Both primary and secondary processes (recycling) of nine major non–renewable construction materials (steel, aluminium, copper, cement, concrete, ceramic, glass, polypropylene and polyvinylchloride (PVC)) have been evaluated in this study. The outlined theoretical exergy efficiency approach assesses the improvement potentials of the present manufacturing processes. The large difference between theoretical and industrial exergy demand suggests that exergy resources are utilised very inefficiently in current technologies. The study reveals that more than 55% of exergy is being lost in current technologies even though a significant amount of waste heat is recovered in different segments of the case study processes. Thus, attention is required to reduce the specific exergy losses through improved process design and introduction of new technology.

The paper presents the Material Flow Analysis for Catalonia (NE Spain) in the period 1996 – 2000. The results show no symptom of neither weak nor strong dematerialization, otherwise the increase in material inputs and consumption a long the period is higher than population and GDP growth; with dominance of non-renewable resources. There is a high dependence on foreign trade. On one hand, imports has increased a long the period analyzed to compensate the lack of primary resources in the own system. On the other hand, the price of exports is higher than imports, supposing important economic input for Catalonia., En este trabajo se presenta una primera estimación del Análisis de Flujos de Materiales entre los años 1996 y 2000 para el caso de Cataluña, una región situada en el noreste de España. Los resultados muestran un crecimiento de los indicadores de entrada de materiales y de consumo muy superior al crecimiento de la población y del Producto Interior Bruto, descartándose la posible tendencia a la desmaterialización absoluta o relativa, y mostrando un fuerte dominio de consumo de recursos no renovables. Asimismo se observa una gran dependencia del extrior, tanto en la entrada de recursos como en las exportaciones. Las importaciones aumentan a lo largo del período analizado, cpmensando la falta de recursos primarios del sistema. Parte de los materiales importados son exportados, mostrando Cataluña como una región de tránsito de mercancías, sometida al Efecto Rótterdam. A la vez una fracción de las importaciones se revende con beneficio para Cataluña siguiendo el comportamiento propio de la zona alta de la curva del Notario.