Comparative assessment of two circularity indicators for the case of reusable versus single-use secondary packages for fresh foods in Spain.

Sustainable packaging is a crucial focus in the context of circular economy efforts. This study evaluates the circularity of two secondary packaging systems used in Spanish fresh food produces: Reusable Plastic Crates and Single-use Cardboard Boxes. A Mass Flow Analysis was performed to assess the material flows in the production and use phases of both systems and two circular indicators were applied: the Material Circularity Indicator and Product Circular Indicator. While most previous studies for single-use packaging use these indicators at the product level, this study applies a system approach since the Reusable Plastic Crates can be reused 100 times. The functional unit was defined as the distribution of 1000 tonnes of fresh products, resulting in the distribution of 6,666,700 packages with 15 kg of products. The Material Circularity Indicator and Product Circular Indicator results show that Reusable Plastic Crates are more circular than Single-use Cardboard Boxes. The Product Circular Indicator provides a more comprehensive assessment of circularity by considering multiple life cycle stages, efficiency, and unrecoverable waste, resulting in a difference in circularity evaluations. The indicators used have limitations as they do not consider the resource stock. Further research is needed to explore this aspect.

'Small-scale' tourism versus traditional tourism: Which will be the new key to achieve the desired sustainable tourism?

The tourism sector after COVID-19 has raised different concerns that have lead to a development towards a more sustainable model of tourism. After the health crisis, the increase in environmental awareness of tourists has become evident. In this context, the great paradigm of 'small-scale' tourism has been developed as opposed to traditional tourism. The present work seeks to contribute to sustainable development in the Spanish tourism sector, comparing a hostel in Cantabria (considered as 'small scale' /religious tourism) and a hotel in Lloret de Mar (considered as a traditional tourism) one using the Life Cycle Assessment (LCA) methodology to verify advantages and disadvantages of both types of tourism. The functional unit (FU) used was 'per guest night with breakfast included'. The results have revealed similar results for both establishments in all impact categories, as can be seen in its contribution to Climate Change (4.41 kg CO2 eq./FU caused by the hotel and 4.78 kg CO2 eq./FU by the hostel). The electricity consumption and the impact of the breakfast in the hostel were identified as main contributors to environmental burdens (with 76.72 % of the hotel's impact to climate change and 77.36 % for the hostel); hence, improvement opportunities envisaged were focused on these critical points. On the one hand, a biomass boiler, a solar water-heating system and a hybrid solar/biomass heating are considered a more sustainable alternatives related to electricity. Natural gas and diesel Consumption, respectively. On the other hand, oatmeal, Greek yoghurt and berries are good options for a breakfast with a reduced environmental impact. It is also important to implement responsible and green practices in order to achieve more environmentally sustainable alternative and traditional accommodations. Therefore, it can be concluded by stating that LCA is a tool capable of identifying and studying the processes with the highest environmental impact in order to find out the most sustainable form of tourism.

Life cycle assessment to address the environmental impacts of tourism in a Spanish tourist destination: The case of Rias Baixas (Galicia) holidays.

Tourism has grown steadily in recent decades, becoming a strategic sector for the economy in many countries. However, the environmental impacts associated with tourism have also experienced an upward trend. In this sense, innovation is needed in the tourism sector, to move towards new models and strategies that integrate environmental sustainability with the social aspects of the sector. In this study, a holistic assessment of the environmental impact of tourism has been carried out using the Life Cycle Assessment (LCA) method, considering all stages of tourism activity: transportation from the place of origin to destination and back, accommodation, catering, and activities conducted. For this purpose, a case study has been carried out based on a typical trip made from Madrid to Rías Baixas (Galicia), considering a four-night stay and the performance of two activities (music festival and cultural museum) at the destination. Two alternative transportation scenarios (train or plane) have been defined to analyze the influence of the type of transportation on the overall impact. Other touristic activities such as visiting gardens or thermal baths instead of visiting a cultural museum or attending a music festival have been analyzed and it has been found that the thermal baths and the museum have the greatest environmental impacts. Transportation was the biggest contributor to most of the environmental impacts in the selected categories. On the other hand, the stay at the destination has stood out due to the impact of the consumption of food and energy used at the accommodation facility. The impact of the activities conducted at the destination is also worth highlighting. Finally, alternative scenarios for transportation have shown that the mode of transportation selected is key for lowering the overall environmental impact of the stay at the destination, highlighting the public transportation alternative, such as the train, as the most environmentally friendly option.

Life cycle assessment on calcium zincate production methods for rechargeable batteries.

The world's energy transition from fossil to renewable energy is unthinkable without further research in energy storage. Decreasing the environmental impacts from the production of energy storage technologies is essential for achieving a green energy transition. Calcium Zincate (CAZN) is used as active material in rechargeable zinc-based batteries (and other products, such as heterogeneous catalysts for biodiesel or antifungal products). They present a low-cost, safer, alternative to Lithium based batteries and are targeted as replacement solutions for lead-acid batteries. We propose a novelty in the synthesis of CAZN, the hydro-micro-mechanical process (HMMS). The residence time of this new route is about 20 times lower than the traditional processes, so its production needs less infrastructure and can deliver quicker at an industrial scale. In addition, laboratory tests indicate that HMMS CAZN has more reaction surface area and the activation of the battery is 1.77 times faster. Using the life cycle assessment (LCA) method, we compare this new process with the current best option, hydro-thermal synthesis (HTS). The cradle-to-gate results per kg of CAZN already indicates that HMMS is an environmentally better alternative for all indicators; especially when considering the normalization of the results with the residence time and the surface area, HMMS delivers better results, with improvements of 97 % in global warming, for instance. With this, we demonstrate that, outside of the cradle-to-gate, variables that make the final products better service units or give more function should be considered as valuable additional information when deciding among alternatives. This also highlights the importance of life cycle thinking when working with chemical processes and substances. In the sensitivity analysis, we developed 7 scenarios related to the energy demand of the processes, and we incorporated the projection in the European electricity mix for 2030 and 2050.

Linking LCA literature with circular economy value creation: A review on beverage packaging.

The ever-increasing volume of packaging waste is widely recognised as a key global environmental challenge. Packaging is thus a central concern for advocates and analysts of circular economy (CEc), who often apply the life cycle assessment (LCA) methodology when measuring the environmental impacts of products and packaging. We undertook a systematic literature review as a research method, and in-depth analysis to ascertain the extent to which the new CEc paradigm has been integrated in LCA methodology applied to beverage packaging and reported in scientific papers. Carefully developed search strings returned 866 articles relevant to our enquiry from the databases of SCOPUS and Web of Science. Applying our selected eligibility criteria, we extracted a subset of 51 articles for in-depth analysis. The analysed literature shows the links between the quality of packaging material for recycling and the profoundness of the LCA studies. The paper provides the following set of recommendations for enhancing the future practice in development of the scientific LCAs for beverage packaging: (i) taking all direct and indirect factors into account when assessing the refillable beverage packaging system and conducting break-even analysis in order to achieve impartial comparative assessments of single-use and refillable systems; (ii) developing proxies in cases when actual data is lacking with which to model the recycling scenarios for exported secondary materials and hence improving the accuracy of recycling rate assessments in LCA models; (iii) improving the definition of the LCA function by introducing multiple loops of the packaging material and assessing qualitative changes in the material resulting from the multiple-recycling process. Thus improved practice of LCAs could better inform and improve the design of new packaging strategies aimed at prolonging the life of packaging materials in the technosphere, equally fulfilling the principles of the CEc.

Polylactic Acid/Polycaprolactone Blends: On the Path to Circular Economy, Substituting Single-Use Commodity Plastic Products.

Circular economy comes to break the linear resource to waste economy, by introducing different strategies, two of them being: using material from renewable sources and producing biodegradable products. The present work aims at developing polylactic acid (PLA), typically made from fermented plant starch, and polycaprolactone (PCL) blends, a biodegradable polyester, to study their potential to be used as substitutes of oil-based commodity plastics. For this, PLA/PCL blends were compounded in a batch and lab scale internal mixer and processed by means of injection molding. Tensile and impact characteristics were determined and compared to different thermoplastic materials, such as polypropylene, high density polyethylene, polystyrene, and others. It has been found that the incorporation of PCL into a PLA matrix can lead to materials in the range of 18.25 to 63.13 megapascals of tensile strength, 0.56 to 3.82 gigapascals of Young's modulus, 12.65 to 3.27 percent of strain at maximum strength, and 35 to 2 kJ/m2 of notched impact strength. The evolution of the tensile strength fitted the Voigt and Reuss model, while Young's modulus was successfully described by the rule of mixtures. Toughness of PLA was significantly improved with the incorporation of PCL, significantly increasing the energy required to fracture the specimens. Blends containing more than 20 wt% of PCL did not break when unnotched specimens were tested. Overall, it was found that the obtained PLA/PCL blends can constitute a strong and environmentally friendly alternative to oil-based commodity materials.