Measuring and monitoring the transition to the circular economy of universities: CExUNV.

The circular economy (CE) has been identified as a critical strategy to contribute to sustainable development and the achievement of the Sustainable Development Goals of the 2030 Agenda, being one of the biggest challenges for society in general and organisations in particular. Hence, various methods have been developed in recent years to measure the level of circularity of organisations, such as methodologies, indicators, metrics and CE tools. Universities, as education, research and community service organisations, play a key role in the promotion of and transition to the CE. Therefore, they require methods that enable them to quantify and monitor their level of circularity. However, it has been shown that CE methods developed for organisations are not suitable for such complex institutions, and, to date, no sector-specific methods have been developed. In this context, it has become necessary to develop a useful method to quantify and monitor the current level of circularity, assess its progress and facilitate decision-making on circularity that addresses the specific needs of this type of organisation. Thus, a set of 82 CE indicators and their metrics, specific to universities, has been proposed. They have been implemented in an Excel spreadsheet tool called CExUNV, in order to promote and facilitate their use. In addition, 41 improvement actions have been suggested to guide and assist universities in their progress towards CE.

Exploring how waste management is being approached in green building rating systems: A case study.

Green building rating systems (GBRS) propose sets of indicators to measure the level of sustainability of buildings, and include waste as one of the categories to be assessed. Yet, both the number of indicators and their aim, as well as the waste fraction they refer to, vary greatly from one system to another. This study identifies the waste-related indicators included in 10 global GBRS. They are classified on the basis of different criteria (waste fraction assessed, stages of the life cycle of the building, waste hierarchy and stages that make up the waste management system) so as to make it possible to subsequently analyse the importance given to each indicator through the specific weightings of each GBRS. Finally, the indicators are implemented in the case study of a building located in Colombia, in order to quantify the current level of sustainability achieved in the waste category of each system and to propose improvement actions that allow this score to be improved. In this way, it is shown that proper waste management can increase the level of sustainability of a building.

Environmental implications of reprocessing agricultural waste into animal food: An experience with rice straw and citrus pruning waste.

The aim of this study is to conduct an environmental comparison, by applying the life cycle assessment (LCA) methodology, of two different compositions for animal foods each with two different nutritional contents ('high' for the lactation period, and 'low' for the rest of the year). Thus, for each nutritional content, the environmental performance of producing animal feed with a traditional composition mainly based on cereals is compared with a composition based on a mixture of biomass obtained from rice straw and citrus pruning waste. It was observed that the reprocessing of rice straw and citrus pruning waste into animal feed offered environmental potential compared to the current alternative of being burned in the fields. The environmental impact category global warming is especially improved, with impact reductions of up to 50% and 95%, respectively, for high and low nutritional content compositions. In addition, the alternatives proposed herein make it possible to avoid all the inconvenience and impacts on the health of the population living near the fields.

Bayesian and network models with covariate effects for predicting heating energy demand.

The spatial effect is an element presented in many geostatistical works and it should be incorporated into studies regarding the heating energy demand of residential building stocks. The most common approaches have been made by simple descriptive statistics or using analyses by Markov random fields. In this work, we propose two different methods. First, the Stochastic Partial Differential Equation with the Integrated Nested Laplace Approximation to model the variable heating energy demand in Castellón de la Plana, Spain also considering covariates and the spatial effect. Second, simulated street networks for analysing data. We describe and take advantage of the Bayesian methodology in the modelling process in all the scenarios, including covariates and the possibility of creating a simulated street network with the data for the modelling issue. Our results show that the spatial location of the building is a crucial element to study the heating energy demand using both methodologies.

Sustainability reports as a tool for measuring and monitoring the transition towards the circular economy of organisations: Proposal of indicators and metrics.

Sustainability reports may play an important role as a supporting tool in the transition of organisations towards more circular economy models, since their content can help to measure, monitor and communicate the organisations' transition and to establish goals in the short/medium term. The aim of this study is to determine whether it is possible to calculate indicators capable of measuring the transition of organisations towards circularity from the information that they are currently communicating in their Corporate Sustainability Reports (CSRs), and what information would need to be incorporated in these reports to successfully carry out this procedure. To this end, by applying a three-step methodology, 34 indicators grouped into 10 categories were proposed to measure the level of circularity of organisations. This was completed with a detailed proposal of units/metrics to measure the indicators, based on those that organisations commonly use in their CSRs. For this purpose, information from 8 international programmes/frameworks that measure circularity at the territorial level was combined with circularity information that organisations are currently communicating in their CSRs. Finally, the proposed set of indicators and metrics were applied to a Spanish organisation dedicated to the forestry and paper sector with a CSR based on GRI-Standards. The results demonstrated that 25 of the 34 proposed indicators (74%) can be measured directly using the information included in the CSRs.

Carbon footprint in Higher Education Institutions: a literature review and prospects for future research.

Higher Education Institutions (HEI) or universities, as organisations engaged in education, research and community services, play an important role in promoting sustainable development. Therefore, they are increasingly linked to the initiative of calculating their carbon footprint (CF), which is a tool to assess sustainability from the perspective of greenhouse gas (GHG) emissions. The aim of this study is to carry out a systematic review of the current situation of CF assessment in academic institutions by analysing different key elements, such as the time period, methodologies and practises, calculation tools, emission sources, emission factors and reduction plans. The review protocol considered articles published until March 2021. Of the articles reviewed, 35 are aimed specifically at calculating the CF of HEI, while the remaining articles consist of review, activity-specific CF assessment or GHG emission reduction articles. Clear differences have been identified when results are compared for the normalised CF (average of 2.67 t CO2e/student, ranging from 0.06 to 10.94) or the percentage of carbon offsetting, only considered in 14% of the studies and ranging from 0.09 to 18%. The main reason for this is the lack of standardisation as regards the time metric (year, semester), functional unit (student, employee, area) and data collection boundary (scope 1, 2, 3), the emissions sources and emission factors, mainly for scope 3 (water consumption and treatment, waste treatment, office, ICT and laboratory consumables, commuting and travel, construction materials, canteens, etc.), and the inclusion or not of the effect of carbon offset projects to offset the CF (aim of the project and absorption sources and factors). However, despite the differences, a reduction over time is clearly observed. Therefore, CF in HEI requires further improvements and solutions to a number of challenges, including the definition of representative emission sources, the creation of a robust emission factor database and the development of tools/methodologies that cover all the needs of this type of organisation.

Repair vs. replacement: Selection of the best end-of-life scenario for small household electric and electronic equipment based on life cycle assessment.

This study presents a methodology designed for selecting, from an environmental point of view, the best end-of-life scenario for electric and electronic equipment which breaks before the end of its life span. To this end, the environmental impact of the life cycle of the equipment is evaluated for two different end-of-life scenarios: repair & reuse vs. replacement. As a case study, the proposed methodology is applied to a representative sample of nine categories of small household electric and electronic equipment (120 appliances). Repair & reuse scenarios consider the life span and the typical failures and repairs associated with each electric and electronic equipment category and the use of the repaired equipment until the remaining life span after its breakage. Replacement scenarios also consider the life span associated to each electric and electronic equipment category and the replacement of the broken equipment by an equivalent during the remaining life span after its breakage. The environmental impact obtained for both scenarios for each small household electric and electronic equipment category is compared in order to identify the best end-of-life scenario. To do so, the life cycle assessment methodology is applied, using CML and ReCiPe as midpoint- and endpoint-impact assessment methods, respectively. The results indicate that for all the analysed categories, the repair & reuse scenarios generally prove environmentally better than replacement scenarios, as Directive 2012/19/EU promotes. However, for some types of failure, e.g. those related to motors or printed circuit boards, if the failure occurs at the end of its life span, replacement is a better option than repair & reuse, since the environmental impact of the repair activities is not offset by the environmental benefits of extending the useful life until the end of the life span.

Identifying design guidelines to meet the circular economy principles: A case study on electric and electronic equipment.

This study presents a methodology that allows the analysis of how an existing product design meets the design guidelines required from the circular economy perspective, and which are the design guidelines that would need to be incorporated into its design to become a better circular design product. For that, as a starting point, the design guidelines required for the circular product design have been identified from an extensive literature review. Then, criteria have been defined to measure the margin of improvement of a product design based on the level of compliance of each circular design guideline, and the relevance of each circular design guideline for the specific product category to which it belongs. Finally, the methodology has been applied to a representative sample of 127 appliances belonging to different categories of small household electrical and electronic equipment. The circular design guidelines related to extending life span and to product/components reuse have been identified as those that more urgently need to be incorporated, while the urgency of those related to connectors or product structure is moderate.

A survey on consumers' attitude towards storing and end of life strategies of small information and communication technology devices in Spain.

This study analyses the current habits and practices towards the store, repair and second-hand purchase of small electrical and electronic devices belonging to the category of information and communication technology (ICT). To this end, a survey was designed and conducted with a representative sample size of 400 individuals through telephone interviews for the following categories: MP3/MP4, video camera, photo camera, mobile phone, tablet, e-book, laptop, hard disk drive, navigator-GPS, radio/radio alarm clock. According to the results obtained, there is a tendency to store disused small ICT devices at home. On average for all the small ICT categories analysed, 73.91% of the respondents store disused small ICT devices at home. Related to the habits towards the repair and second-hand purchase of small ICT devices, 65.5% and 87.6% of the respondents have never taken to repair and have never purchased second-hand, respectively, small ICT devices. This paper provides useful and hitherto unavailable information about the current habits of discarding and reusing ICT devices. It can be concluded that there is a need to implement awareness-raising campaigns to encourage these practices, which are necessary to reach the minimum goals established regarding preparation for reuse set out in the Directive 2012/19/EU for the category small electrical and electronic equipment.

Temporal evolution of the environmental performance of implementing selective collection in municipal waste management systems in developing countries: A Brazilian case study.

The aim of this study is to analyse the evolution of the municipal solid waste management system of João Pessoa (Brazil), which was one of the Brazilian pioneers cities in implementing door-to-door selective collection programmes, in order to analyse the effect of policy decisions adopted in last decade with regard to selective collection. To do it, this study focuses on analysing the evolution, from 2005 to 2015, of the environmental performance of the municipal solid waste management (MSWM) system implemented in different sorting units with selective collection programmes by applying the Life Cycle Assessment (LCA) methodology and using as a starting point data collected directly from the different stakeholders involved in the MSWM system. This article presents the temporal evolution of environmental indicators measuring the environmental performance of the MSWM system implemented in João Pessoa by sorting unit, for each stage of the life cycle of the waste (collection, classification, intermediate transports, recycling and landfilling), for each waste fraction and for each collection method (selective collection or mixed collection), with the aim of identifying the key aspects with the greatest environmental impact and their causes. Results show on one hand, that environmental behaviour of waste management in a door-to-door selective collection programme significantly improves the behaviour of the overall waste management system. Consequently, the potential to reduce the existing environmental impact based on citizens' increased participation in selective collection is evidenced, so the implementation of awareness-raising campaigns should be one of the main issues of the next policies on solid waste. On the other hand, increasing the amount of recyclable wastes collected selectively, implementing alternative methods for valorising the organic fraction (compost/biomethanization) and improving the efficiency of the transportation stage by means of optimizing vehicles or routes, are essential actions to reduce the overall net environmental impact generated by the MSWM system.

Attitude of the stakeholders involved in the repair and second-hand sale of small household electrical and electronic equipment: Case study in Spain.

The European legal framework for Electrical and Electronic Equipment (EEE) and Waste Electrical and Electronic Equipment (WEEE) (Directive 2012/19/EU) prioritises reuse strategies against other valorisation options. Along these lines, this paper examines the awareness and perceptions of reusing small household EEE from the viewpoint of the different stakeholders involved in its end-of-life: repair centres, second-hand shops and consumers. Direct interviews were conducted in which an intended survey, designed specifically for each stakeholder, was answered by a representative sample of each one. The results obtained from repair centres show that small household EEE are rarely repaired, except for minor repairs such as replacing cables, and that heaters, toasters and vacuum cleaners were those most frequently repaired. The difficulty of accessing cheap spare parts or difficulties during the disassembly process are the commonest problems observed by repair technicians. The results obtained from second-hand shops show that irons, vacuum cleaners and heaters are the small household EEE that are mainly received and sold. The results according to consumers indicate that 9.6% of them take their small household EEE to be repaired, while less than 1% has ever bought a second-hand small household EEE. The main arguments for this attitude are they thought that the repair cost would be similar to the price of a new one (for repairs), and hygiene and cleaning reasons (for second-hand sales).

Disassembly properties and material characterisation of household small waste electric and electronic equipment.

This paper is focused on characterising small waste electric and electronic equipment, specifically small household appliances, from two different points of views: disassembly properties and material identification. The sample for this characterisation was obtained from a selective collection campaign organised in Castellón de la Plana (Spain). A total amount of 833.7kg (749 units) of small waste electric and electronic equipment was collected, of which 23.3% by weight and 22.4% by units belonged to the subcategory household equipment. This subcategory, composed of appliances such as vacuum cleaners, toasters, sandwich makers, hand blenders, juicers, coffee makers, hairdryers, scales, irons and heaters, was first disassembled in order to analyse different aspects of the disassembly process for each equipment type: type of joints, ease of identification of materials, ease of access to joints for extracting components, ease of separation of components from the whole, uniformity of tools needed for the disassembly process and possibility of reassembly after disassembly. Results show that the most common joints used in these equipment types are snap-fits and screws, although some permanent joints have also been identified. Next, the material composition of each component of each appliance belonging to each equipment type was identified visually and with additional mechanical trials and testing. It can be observed that plastic and electric/electronic components are present in all the equipment types analysed and are also the material fractions that appear with higher percentages in the material composition: 41.1wt% and 39.1wt% for the plastic fraction and electric/electronic components, respectively. The most common plastics are: polypropylene (PP), acrylonitrile butadiene styrene (ABS) and polycarbonate (PC), while the most common electric/electronic components are: cable, plug and printed circuit boards. Results also show that disassembly properties and material characterisation vary widely from one equipment type to another.

Potential reuse of small household waste electrical and electronic equipment: Methodology and case study.

This study proposes a general methodology for assessing and estimating the potential reuse of small waste electrical and electronic equipment (sWEEE), focusing on devices classified as domestic appliances. Specific tests for visual inspection, function and safety have been defined for ten different types of household appliances (vacuum cleaner, iron, microwave, toaster, sandwich maker, hand blender, juicer, boiler, heater and hair dryer). After applying the tests, reuse protocols have been defined in the form of easy-to-apply checklists for each of the ten types of appliance evaluated. This methodology could be useful for reuse enterprises, since there is a lack of specific protocols, adapted to each type of appliance, to test its potential of reuse. After applying the methodology, electrical and electronic appliances (used or waste) can be segregated into three categories: the appliance works properly and can be classified as direct reuse (items can be used by a second consumer without prior repair operations), the appliance requires a later evaluation of its potential refurbishment and repair (restoration of products to working order, although with possible loss of quality) or the appliance needs to be finally discarded from the reuse process and goes directly to a recycling process. Results after applying the methodology to a sample of 87.7kg (96 units) show that 30.2% of the appliances have no potential for reuse and should be diverted for recycling, while 67.7% require a subsequent evaluation of their potential refurbishment and repair, and only 2.1% of them could be directly reused with minor cleaning operations. This study represents a first approach to the "preparation for reuse" strategy that the European Directive related to Waste Electrical and Electronic Equipment encourages to be applied. However, more research needs to be done as an extension of this study, mainly related to the identification of the feasibility of repair or refurbishment operations.

Evolution of sorted waste collection: a case study of Spanish cities.

This work analyses how selective collection evolved over the period 1998-2007 in Spanish towns and cities with more than 50 000 inhabitants. To do so, both the legislation in force during the years included in the study and logistic factors, such as the radius of action of the pick-up points, were taken into account. Information about the towns and cities was obtained from a survey sent out in 1998 and 2007 to the councils of the municipalities included in the study. The results obtained in the two years show that the most widely implemented separate collection system in 1998 no longer existed in 2007 but, in order to comply with the law, had been transformed by adding new fractions, above all that of lightweight packaging. To determine whether the targets set by law as regards recovery and recycling were met in the two years, an efficiency indicator was used to evaluate the effectiveness of the collection systems. Results show how separation increased in the paper/board and glass fractions.

Analysis of collection systems for sorted household waste in Spain.

This work analyses the separate collection systems used in Spanish towns with between 5000 and 50,000 inhabitants. The study looks at the systems and their efficiency by means of the indicators fractioning rate, quality in container rate and separation rate. The results obtained are compared with those from a similar study conducted earlier that was applied to towns and cities with populations over 50,000. It can be concluded that the most widely implemented system in Spain involves the collection of mixed waste from kerbside bins and picking up paper/cardboard, glass and lightweight packaging from drop-off points. Findings show that the best system is the one that collects mixed waste, organic material and multiproduct waste door-to-door, and glass from drop-off points. The indicator separation rate made it possible to establish beta regression models to analyse the influence of the following logistic variables: inhabitants per point (people/pt), time (years) and frequency of collection (freq). From these models it can be seen that people/pt has a negative effect on all the fractions, while freq and years have a positive effect in the case of paper.

Comparison of different collection systems for sorted household waste in Spain.

The purpose of this study was to identify the different selective collection systems implemented in Spanish cities and to analyse the efficiency and extent to which the targets proposed by current law are met in each case. After defining the indicators to be used to quantify the efficiency of a selective collection system, a survey was designed to gather the information needed to calculate them. This survey was sent out to all Spanish cities with a population of over 50,000 inhabitants. Four different selective collection systems were also identified. For each of the four cases the indicators were calculated and analyzed to determine which one was the best system. The best values were obtained from the system with separation in five fractions: paper/cardboard, glass and lightweight packaging at drop-off points, organic waste and mixed waste in kerbside bins. Two regression models (linear and exponential) were developed in systems with enough data to explain and predict the variation in the amounts of materials that were separated correctly into containers, depending on the distance between containers and citizens. Nevertheless, the percentages of separation at source of paper/cardboard and lightweight packaging are still far from reaching the targets set by law.