Environmental and socio-economic effects of construction and demolition waste recycling in the European Union

The recovery rate of construction and demolition waste (CDW) in the European Union (EU) is at 89 % and thus high relative to other waste streams. However, the relatively high figure can be misleading because it typically does not correspond to high-value material recovery but rather "poor" levels of circularity. From a life-cycle perspective, we assess the environmental impacts and costs of 12 CDW material fractions relying on alternative pathways and treatment technologies. The results indicate important trade-offs in the transition towards the circular economy. Indeed, recycling of concrete, bricks, gypsum, and ceramics and tiles represent the best environmental performance but also the most expensive pathway. However, when shifting from landfill to recycling the total societal costs in the EU are reduced mainly due to the lower external costs. Overall, recycling CDW in the EU with advanced technologies would save about 264 kg CO2-eq t-1 with a cost of 25 EUR t-1. The maximum potential for recycling under current technology in the EU would lead to an annual total reduction of about 33 Mt. of CO2-eq using 2020 as reference year. The fractions with the highest potential for improving current waste management practices in terms of environmental improvements are concrete and bricks. The economic and non-economic barriers for realising this potential at EU level are discussed in relation to the European Green Deal and the EU's circular economy objectives.

Management practices for compostable plastic packaging waste: Impacts, challenges and recommendations

The EU Green Deal aims at solving the challenges related to plastic production, (mis-)use, and pollution. While the bioplastic industry is identified as one of the possible avenues to tackle the problem, bioplastic waste collection and management practices are still far from full-development and harmonisation. To inform policy makers on the best practices and their feasibility, this study quantifies environmental and economic impacts of compostable plastic packaging (CPP) waste management schemes by means of Life Cycle Assessment and Costing. Results show that, with respect to climate change and financial costs, the scheme leading to the highest benefits is collecting CPP with conventional plastic waste followed by mechanical sorting and recycling (saving ca. 306 kg CO2eq. t-1 at a net income of 3.7 EUR t-1). The second best option is collecting CPP with bio-waste followed by biological treatment (saving ca. 69 kg CO2eq. t-1 at a cost of 197 EUR t-1). Collecting CPP with conventional plastics followed by sorting and biological treatment is to be avoided. The trend on the other impact categories generally follows climate change. Ideally, closed loop is therefore preferred, but conditioned by (i) having high share of CPP in municipal waste (else sorting is economically unfeasible), (ii) good citizen's behaviour at source-segregation, and (iii) an established market for secondary material. Currently, overall benefits are limited by the low amounts, suggesting that the management choice could ultimately be based on rather simple technical and economic feasibility criteria while regulatory and management efforts should be focused on other waste streams with greater implications on environment.

Operational Framework to Quantify "Quality of Recycling" across Different Material Types

Many pledges and laws are setting recycling targets without clearly defining quality of recycling. Striving to close this gap, this study presents an operational framework to quantify quality of recycling. The framework comprises three dimensions: the Virgin Displacement Potential (VDP); In-Use Stocks Lifetime (IUSL); and Environmental Impact (EI). The VDP indicates to what extent a secondary material can be used as a substitute for virgin material; the IUSL indicates how much of a certain material is still functional in society over a given time frame, and the EI is a measure of the environmental impact of a recycling process. The three dimensions are aggregated by plotting them in a distance-to-target graph. Two example calculations are included on poly(ethylene terephthalate) (PET) and glass. The results indicate that the recycling of bottle and container glass collected via a deposit-refund system has the lowest distance-to-target, at 1.05, and, thus, the highest quality of recycling. For PET bottles, the highest quality of recycling is achieved in closed-loop mechanical recycling of bottles (distance to optimal quality of 0.96). Furthermore, sensitivity analysis indicates that certain parameters, e.g., the collection rate for PET bottles, can reduce the distance-to-target to 0.75 when all bottles are collected for recycling.

Climate change mitigation potential of transitioning from open dumpsters in Peru: Evaluation of mitigation strategies in critical dumpsites

Waste management is a critical policy towards the reduction of environmental impacts to air, soil and water. Many Latin American countries, however, lack a correct waste management system in many cities and rural areas, leading to the accumulation of unmanaged waste in illegal or unregulated dumpsites. The case of Peru is of interest, as it hosts 5 of the 50 largest dumpsites in the world. An erratic waste management compromises climate actions for Peru to commit with the Paris Agreement, as no correct closure systems are established for these dumpsites. Therefore, the main objective of this study is to assess the contribution of the past and present biodegradable waste produced and disposed of in the most critical open dumpsters to the overall annual greenhouse gas (GHG) emissions of Peru using the IPCC model. Thereafter, the climate change mitigation potential of possible dumpsite closure strategies based on a selection of technologies, including economic feasibility, were estimated. Results show that cumulative GHG emissions in 2018 for the 24 critical dumpsites evaluated added up to 704 kt CO₂ eq. and a cumulative value of 4.4 Mt CO₂ eq. in the period 2019-2028, representing over 40 % of solid waste emissions expected by 2030. Mitigation potentials for these emissions tanged from 91 to 970 kt CO₂ eq. in the ten-year period depending on the mitigation strategies adopted. The costs of these strategies are also discussed and are expected to be of utility to complement Peru's waste management commitments in the frame of the Paris Agreement.

Tourism under a life cycle thinking approach: A review of perspectives and new challenges for the tourism sector in the last decades

Sustainable tourism should be promoted as a new system for the sustainable management of resources from a socioeconomic and environmental point of view. For this purpose, it is necessary to develop a tool capable of assessing the impacts associated with the sector and to identify which actions are currently being addressed in order to achieve the desired sustainability. This timely study aims to describe the current framework of Life Cycle Assessment (LCA) and its application to the tourism sector. To address these questions, a total of 83 documents (77 reviews and 6 international reports) were evaluated, assessing the geographical distribution, the temporal evolution of the publications, as well as the most relevant characteristics of the tourism industry articles were evaluated such as, life cycle inventory (LCI), system boundaries, functional unit (FU), methods, environmental indicators and impact categories considered. The study identifies key recommendations on the progression of LCA in tourism sector. As important results, it stands out that 94 % of articles were from the last decade and 21 % of the articles reviewed cover sustainable tourism term, considering the three dimensions. This review showed that in LCA studies the most common method was CML 2001; the most widely used environmental indicator was the Carbon Footprint (CF) and the Global Warming Potential (GWP) was the impact category used in all the studies. Hence, LCA is a highly effective tool capable of assessing direct and indirect carbon emissions in tourism as well as the socioeconomic and environmental impacts generated in this sector. COVID-19 pandemic is also an object of discussion in the framework of the sustainable tourism together with advocating support for the eco-labelling and digitalisation of the tourism experiences as valuable tools to minimize environmental negativities, to promote mechanisms to access green markets and to frame successful synergies.

Towards a Water-Energy-Food (WEF) nexus index: A review of nutrient profile models as a fundamental pillar of food and nutrition security

The Water-Energy-Food (WEF) nexus approach should be promoted as a tool for sustainable management of resources through the interconnection of these three fundamental pillars. Particularly, food security must ensure healthy and balanced diets for everyone, but selecting individual indicators to assess all slants covered by this element is not an easy task. Hence, the objective of this paper is two-fold, to review nutrient profiling (NP) models that allow to categorize foods and evaluate diets based on their nutritional quality, and to choose the most appropriate model to be used within a WEF nexus index. To address this issue, a total of 159 documents were assessed, appraising the geographic distribution, and time evolution of the publications, as well as the characteristics and potential applications of the NP systems. The review concludes that the NRF9.3. model is the most liable option to be used in a WEF nexus index, presenting the best characteristics by means of the definition of scores and thresholds, and the use of an 'across-the-board' criteria and a reference quantity of 100 kcal, alongside offering higher ability to assess diets and foods than the other competitive model (HEI) through the evaluation of nutrients to encourage instead of foods. A secondary outcome of the review is the identification of the NP models as a useful tool to enable institutions with information to establish policies in the field of public health and facilitating the decision-making process according to the current healthy claims.

Techno-economic and environmental assessment of methane oxidation layer measures through small-scale clean development mechanism - The case of the Seychelles

Unclosed coastal landfills in small island developing states are major sources of greenhouse gases and other environmental impacts. This is a major problem for sustainable waste management systems mainly due to the lack of economic resources. The clean development mechanism (CDM) appears as a possibility to facilitate sustainable financing. Implementing a methane oxidation layer (MOL) emerges as a feasible technical option for this kind of small landfills since landfill gas extraction is usually not viable. This paper presents a techno-economic and environmental assessment of MOL implementation in the Providence landfill (Seychelles) as a small-scale CDM measure. Results show that the MOL measure could avoid by 2030 between 94 and 20 kt CO₂ eq. Concerning profitability, results clearly show that it depends on the existence of stabilized biomass material within the island. Thus, the MOL measure starts to be profitable in some scenarios for certified emission reductions (CER) prices higher than 26 €/t CO₂ eq. that seem possible depending on the emissions' market development. When not profitable under CDM, the MOL measure might be used to reduce CO₂ emissions from the domestic climate effort under the Paris Agreement since the unitary abatement costs is between 10 and 423 €/t CO₂ eq. Moreover, the MOL measure contributes to the sustainable development goals (SDG) achievement - mainly SDG8, SDG13, and SDG14. Finally, results call for a prompt action in Seychelles since the sooner the MOL is implemented after the landfill is closed, the more profitable.

Regionalized Strategies for Food Loss and Waste Management in Spain under a Life Cycle Thinking Approach

Food loss and waste (FLW) has become a central concern in the social and political debate. Simultaneously, using FLW as a bioenergy source could significantly contribute to closing the carbon cycle by reintroducing energy into the food supply chain. This study aims to identify best strategies for FLW management in each of the 17 regions in Spain, through the application of a Life Cycle Assessment. To this end, an evaluation of the environmental performance over time between 2015 and 2040 of five different FLW management scenarios implemented in a framework of (i) compliance and (ii) non-compliance with the targets of the Paris Agreement was performed. Results revealed savings in the consumption of abiotic resources in those regions in which thermal treatment has a strong presence, although their greenhouse gas (GHG) emissions in a scenario of compliance with climate change targets are higher. In contrast, scenarios that include anaerobic digestion and, to a lesser extent those applying aerobic composting, present lower impacts, including climate change, suggesting improvements of 20-60% in non-compliance and 20-80% in compliance with Paris Agreement targets, compared to the current scenarios.

Techno-economic and profitability analysis of food waste biorefineries at European level

Food waste represents a potential source to produce value-added materials replacing the use of virgin ones. However, the use of food waste as feedstock in biorefineries is still at an early stage of development and studies assessing its economic viability at large scale are lacking in the literature. This paper presents a techno-economic and profitability analysis of four food waste biorefineries that use wastes from tomato, potato, orange, and olive processing as feedstock. The study includes the assessment of potentially available quantities of those waste flows in Europe. Due to the low technology readiness level of this kind of biorefineries, a screening methodology to estimate the investment and manufacturing costs as well as two profitability ratios (the return on investment and the payback time) was adopted. Results show that not all the waste feedstocks have the same potential. The most profitable options are those related to implementing fewer plants, namely concentrating the production and capitalising on economies of scale while being at risk of increasing externalities, e.g. due to logistics of the feedstocks.

Prioritizing and optimizing sustainable measures for food waste prevention and management

Food waste has gained prominence in the European political debate thanks to the recent Circular Economy package. Currently the waste hierarchy, introduced by the Waste Framework Directive, has been the rule followed to prioritize food waste prevention and management measures according to the environmental criteria. But when considering other criteria along with the environmental one, such as the economic, other tools are needed for the prioritization and optimization. This paper addresses the situation in which a decision-maker has to design a food waste prevention programme considering the limited economic resources in order to achieve the highest environmental impact prevention along the whole food life cycle. A methodology using Life Cycle Assessment and mathematical programing is proposed and its capabilities are shown through a case study. Results show that the order established in the waste hierarchy is generally followed. The proposed methodology revealed to be especially helpful in identifying "quick wins" - measures that should be always prioritized since they avoid a high environmental impact at a low cost. Besides, in order to aggregate the environmental scores related to a variety of impact categories, different weighting sets were proposed. In general, results show that the relevance of the weighting set in the prioritization of the measures appears to be limited. Finally, the correlation between reducing food waste generation and reducing environmental impact along the Food Supply Chain has been studied. Results highlight that when planning food waste prevention strategies, it is important to set the targets at the level of environmental impact instead of setting the targets at the level of avoided food waste generation (in mass).

Improving images of fluorescent cell labeling by background signal subtraction

The uptake and selective accumulation of fluorescent labels and drugs into organelles of cultured cells currently are widely investigated in biomedical research. In such studies, co-localization procedures are frequently used to identify the accumulation sites of compounds with biological activity. A drawback with fluorescent labeling is the autofluorescence of some cell organelles, which can hinder the precise assessment of co-localization. We report here labeling of the Golgi apparatus of A-549 cells using the photosensitizer zinc(II)-phthalocyanine (ZnPc) and co-localization with the Golgi probe NBD C6-ceramide. The blue autofluorescence signal of mitochondria can be subtracted easily from the original picture by image processing, after which the co-localization of the isolated red ZnPc signal with the green signal from the Golgi probe is considerably improved.