Disseny de reactors fotoquímics: descripció dels models d’emissió de llum per a reactors anulars. Part 1, models clàssics

El disseny d’un reactor químic ha de contemplar normalment,a no ser que puguin simplificar-se, una sèrie de balanços: el de matèria, el d’energia i el de quantitat de moviment. A més d’aquests, un model de reactor fotoquímic ha de considerar el balanç de radiació. Generalment, les equacions que defineixen aquests balanços estan acoblades i s’han de resoldre simultàniament. Aquest article explica com es planteja el balanç de radiació (amb les equacions matemàtiques i el suport gràfic necessari) per al reactor anular en medi homogeni quan la làmpada està centrada a l’eix del reactor. Concretament descriu els models d’emissió clàssics, que es caracteritzen per utilitzarcoordenades cartesianes amb els eixos centrats a la làmpada. El que es fa és presentar aquests models amb les equacions i el suport gràfic necessari per facilitar-ne la seva comprensió i homogeneïtzar la nomenclatura dels diferents models descrits

Product vs corporate carbon footprint: Some methodological issues. A case study and review on the wine sector

Carbon footprint (CF) is nowadays one of the most widely used environmental indicators. The scope of the CF assessment could be corporate (when all production processes of a company are evaluated, together with upstream and downstream processes following a life cycle approach) or product (when one of the products is evaluated throughout its life cycle). Our hypothesis was that usually product CF studies (PCF) collect corporate data, because it is easier for companies to obtain them than product data. Six main methodological issues to take into account when collecting corporate data to be used for PCF studies were postulated and discussed in the present paper: fugitive emissions, credits from waste recycling, use of “equivalent factors”, reference flow definition, accumulation and allocation of corporate values to minor products. A big project with 18 wineries, being wine one of the most important agri-food products assessed through CF methodologies, was used to study and to exemplify these 6 methodological issues. One of the main conclusions was that indeed, it is possible to collect corporate inventory data in a per year basis to perform a PCF, but having in mind the 6 methodological issues described here. In the literature, most of the papers are presenting their results as a PCF, while they collected company data and obtained, in fact, a “key performance indicator” (ie., CO2eq emissions per unit of product produced), which is then used as a product environmental impact figure. The methodology discussed in this paper for the wine case study is widely applicable to any other product or industrial activity

Single-use vs reusable transport packaging: a comparative life cycle analysis

This paper deals with a comparative analysis of two different packaging and transport scenarios, which exemplifies the mplications of choosing between single-use and reusable packaging. In particular, transport of a batch of chemicals by means of disposable fibre drums vs. reusable steel drums is investigated from a life cycle perspective, and the associated environmental impact in terms of Global Warming Potential, Acidification Potential, Gross Energy Requirement and solid waste generation is assessed. Results prove beyond reasonable doubt that, even in the case of durable packaging containers requiring the use of comparatively energy-intensive materials for their production, the reuse scenario is characterized by lower environmental impact indicators across the board, and as such is the most advisable and environmentally sound option.Postprint (author’s final draft

A comparative life cycle assessment of single-use fibre drums versus reusable steel drums

This paper deals with a comparative analysis of two different packaging and transport scenarios, which exemplifies the implications of choosing between single-use and reusable packaging. In particular, transport of a batch of chemicals by means of disposable fibre drums vs. reusable steel drums is investigated from a life cycle perspective, and the associated environmental impact in terms of Global Warming Potential, Acidification Potential, Gross Energy Requirement and solid waste generation is assessed. Results prove beyond reasonable doubt that, even in the case of durable packaging containers requiring the use of comparatively energy-intensive materials for their production, the reuse scenario is characterized by lower environmental impact indicators across the board, and as such is the most advisable and environmentally sound option

Are functional fillers improving environmental behavior of plastics? A review on LCA studies

The use of functional fillers can be advantageous in terms of cost reduction and improved properties in plastics. There are many types of fillers used in industry, organic and inorganic, with a wide application area. As a response to the growing concerns about environmental damage that plastics cause, recently fillers have started to be considered as a way to reduce it by decreasing the need for petrochemical resources. Life cycle assessment (LCA) is identified as a proper tool to evaluate potential environmental impacts of products or systems. Therefore, in this study, the literature regarding LCA of plastics with functional fillers was reviewed in order to see if the use of fillers in plastics could be environmentally helpful. It was interesting to find out that environmental impacts of functional fillers in plastics had not been studied too often, especially in the case of inorganic fillers. Therefore, a gap in the literature was identified for the future works. Results of the study showed that, although there were not many and some differences exist among the LCA studies, the use of fillers in plastics industry may help to reduce environmental emissions. In addition, how LCA methodology was applied to these materials was also investigated

Life cycle assessment of carrier bags and development of a littering indicator

Increased plastic consumption has resulted in high amounts of plastic waste ending up in the environment. Recently, the European Commission (EC) has identified a list of single-use plastics, including plastic bags, most commonly found in the European beaches. As a response, alternatives for plastic carrier bags have been more of a concern. Many life cycle assessment (LCA) studies have been performed to evaluate the environmental profile of different carrier bags; however, without considering the possibility of contribution to the littering problem. Therefore, in this study, an indicator has been introduced, based on an LCA study of carrier bags which was performed in Spain. The indicator is influenced by parameters such as: number of bags to fulfill the functional unit, weight, surface, fee, and biodegradability. In this paper, a comparative LCA of HDPE, LDPE, PP, paper and biodegradable plastic bags is presented. Following that, a littering indicator is introduced to allow a comparison of the risk of littering of the different carrier bags in marine environment. The results given by the Littering Potential indicator rank the bags oppositely to the results given by the LCA as usual. Further research is needed to refine the model and include additional contributing variables

Trends and evolution in the concept of historical towns sustainability

The present study aims to review the scientific literature on sustainable towns by tracking its evolution and trends, with reference to the Sustainable Development Goals localization, and by applying social network analysis to bibliometric science. The bibliometric analysis, implemented over the timeframe 1996-2021, allowed the generation of maps based on network data displaying the relationships among scientific journals, researchers, and countries. Two different bibliometric analyses were performed to explore the scientific literature on “sustainable historical towns” and “sustainable towns’ assessment”. The results were useful to capture the multidimensional nature of sustainable towns by analyzing a large amount of literature data while identifying the main scientific patterns in this field of science. The paper is organized as follows. Sections 1 and 2 briefly introduce the topic and goal of the study. In section 3, the concept of “historical town” is defined by a qualitative and quantitative analysis. In section 4, governance issues related to small size municipalities are described with a focus on the inner peripheral areas.  In Section 5, a review of sustainable urban policy evolution at the global and European levels is presented. Section 6 illustrates the state of the art in sustainability assessment of towns, analyzing the main issues and advancements of SDGs localization in the European historical small and medium-sized towns and rural areas. Section 7 illustrates the methodology and results of the performed bibliometric network analysis. Finally, the main findings of the study and research perspectives are summarized in Section 8

Tackling the relevance of packaging in life cycle assessment of virgin olive oil and the environmental consequences of regulation

Production and consumption of olive oil is very important in Europe, being this product a basic element in the Mediterranean diet since long ago. The project objective is two-fold: a study of the contribution of virgin olive oils (VOOs) usual packaging to the whole life cycle of the product and a study of the environmental consequences of the Spanish Government regulation on VOO packaging. A life cycle assessment (LCA) according to ISO 14044 has been performed using the CML methodology for the impact assessment. The results show that the packaging influence varies from 2 to 300%, depending on the impact category and type of packaging (glass, tin or polyethylene terephtalate). Glass, which is related to higher quality perception by consumers, was found to be the most influencing material (due to its weight); however, this impact may be fairly reduced by applying ecodesign strategies (such as weight reduction and recycled-glass percentage increase). A new Spanish regulation on the mandatory use of non-refillable oilers in HORECA establishments (hotels, restaurants and caterings) aims to provide more quality assurance and better information to consumers; however, it was also found to mean a 74% increase in greenhouse gases emissions. This regulation was deeply discussed at European level and its application was withdraw due to consumers rejection, except for Spain. The findings of the present case study show that LCA and ecodesign should be important tools to be promoted and applied in policy making to reduce non-desirable consequences of regulation