A life cycle assessment approach for nitrogen footprint quantification: the reactive nitrogen indicator.

Among the environmental issues that have recently catalyzed the attention of the scientific world, we must undoubtedly include the perturbation in the biogeochemical flows of nitrogen and phosphorus, which have been identified as one of the major risks on a global scale, also considering its social implications, since the use of macronutrients is essential to guarantee the food needs of the world population. In this context, there is a growing interest in the evaluation of the environmental impact related to this issue, particularly with regard to the effects of changes in the nitrogen cycle and the methods for quantifying them. In the latter field, several researches have recently been developed focusing on the indicator known as the nitrogen footprint, associated with the environmental releases of reactive nitrogen. This study proposes an innovative method to quantify the reactive nitrogen emissions of a product system through the reactive nitrogen indicator; the method is designed using as a reference the requirements of the international standards ISO 14040 and ISO 14044, in order to be aligned with the operating procedures of the life cycle assessment technique, thus differing from the previous approaches to calculate the nitrogen footprint. As part of the study, the proposed method is applied to calculate the reactive nitrogen emissions of a set of agricultural and livestock supply chain products, using secondary inventory data from an internationally recognized database. A validation of the method was also carried out by comparing references in the literature regarding the nitrogen footprint accounting for the same products, generally obtaining a good level of agreement. The proposed method, due to its reproducibility, ease of application and completeness, can therefore be usefully applied to any product system for the calculation of reactive nitrogen emissions, thanks to an innovative approach that meets the requirements of life cycle assessment.

Consequential life cycle assessment of kraft lignin recovery with chemical recycling.

The recovery of kraft lignin from black liquor allows an increasing of the pulp production of a kraft mill (marginal tonnage) and at the same time provide a valuable material that can be used as energy or chemical feedstock. However, because lignin precipitation is an energy- and material-consuming process, the environmental consequences from a life cycle perspective are under discourse. The aim of this study is to investigate, through the application of consequential life cycle assessment, the potential environmental benefits of kraft lignin recovery and its subsequent use as an energy or chemical feedstock. A newly developed chemical recovery strategy was assessed. The results revealed how the use of lignin as energy feedstock is not environmentally advantageous compared to producing energy directly from the pulp mill's recovery boiler. However, the best results were observed when lignin was used as a chemical feedstock in four applications to replace bitumen, carbon black, phenol, and bisphenol-A.

Combining organizational and product life cycle perspective to explore the environmental benefits of steel slag recovery practices.

Sustainability in steel production is considered a global challenge which needs to be faced with coordinated actions. The aim of this study is to assess the environmental improvements of a steel mill in a circular economy perspective, through the Organizational Life Cycle Assessment (O-LCA) and the Product Life Cycle Assessment (P-LCA) methodologies. This study explores to what extent the improvements and the efforts to recover the steel slag can be detected using an organization perspective and making a comparison with the more traditional product perspective. The results obtained show that the case in which the steel slag is recovered has lower impacts than the case in which it is landfilled through both O-LCA and P-LCA applications and that the percentage variations are similar for 8 categories out of 10 demonstrating that for our case study, O-LCA and P-LCA can detect the efforts to recover slag similarly. Two categories, namely ADP-minerals&metals and EP-freshwater, are affected by the greater amount of metal and mineral raw materials needed if the slag is not treated and by the steel slag landfill disposal more significantly. What the results tell us is that the variations obtained for this study in the P-LCA application are greater than those obtained in O-LCA application, due to two methodological aspects, namely the application of allocation procedures and the choice of the system boundaries. Finally, it emerges that O-LCA methodology can detect environmental improvements of circularity practices, but the reduction of the impacts is less clear than P-LCA application. What is transferable is that O-LCA and P-LCA methodologies are not interchangeable to quantify the environmental benefits and address the efforts to improve a process in terms of circularity.

Combination of product environmental footprint method and eco-design process according to ISO 14006: The case of an Italian vinery.

To support the sustainable development of the primary sector, in line with green new deals emerging worldwide, eco-design of new agri-food products is a priority. The wine industry, due to its growing market, has matured the need to develop an approach for understanding the environmental impacts of its products and to develop strategies to reduce such impacts in a life cycle perspective. This study has a two-fold aim: presenting the development of a methodological proposal for the use of PEF and PEF-CR in the eco-design of wine products; testing its applicability in a case study in the wine sector. The methodological proposal considered the combination of ISO 14006 and PEF methods into a procedure consisting of 8 steps. The proposal was successfully applied in the case of an Italian vinery committed to develop a new red wine product with improved performance if compared to its standard red wine production. The study occurred between 2018 and 2020, collecting primary data related to vineyards and vinery operations. Results proved that PEF method and PEF-CR can be effectively used in the eco-design of new wine products with reduced environmental impacts. Moreover, the study confirmed that PEF method can be used within the framework of ISO 14006. The study on standard red wine production confirmed that the fuel and pesticide consumption in the vineyard operation are environmental hotspots. To reduce these impacts, a new selection of Merlot Khorus grapes was made by the Italian vinery. Results of the eco-designed proved that the new product scored a reduction in the potential environmental impacts.

Life Cycle Assessment of Polyurethane Foams from Polyols Obtained through Chemical Recycling.

In this research, the results of the life cycle assessment of polyurethane (PUR) foams with different recycled polyol contents are presented. A methodological framework implementing laboratory activities directly into the life cycle assessment has been developed. Laboratory activities made the primary data related to the recycled polyol production available through the glycolysis of polyurethane scraps and the subsequent production and characterization of the foams. Five different formulations were analyzed with glycolyzed polyol content ranging from 0 to 100%. A comprehensive set of impact categories was considered. To ensure the robustness of the results, the influence of two different end-of-life allocation approaches was investigated, and the model was subjected to sensitivity and uncertainty analyses. Formulations with recycled content of 50 and 75% scored better environmental impacts compared to others. The main contributions to the overall impact resulted to be related to the production of isocyanate and virgin polyol. Physical characteristics such as density and thermal conductivity emerged as the main variables to be considered to minimize the overall environmental impacts of PUR foams.

Life Cycle Assessment Framework To Support the Design of Biobased Rigid Polyurethane Foams.

A methodological framework implementing laboratory activities and life cycle assessment is presented and applied to determine which parameters should be considered to develop biobased rigid polyurethane foams for thermal insulation with improved environmental performances when compared to their fossil counterparts. The framework was applied to six partially biobased (produced from bio-based polyols obtained from azelaic acid and/or lignin) and one fossil-based formulations. A comprehensive set of impact assessment categories was investigated including uncertainty and sensitivity analysis. Results proved that physical characteristics such as thermal conductivity and density are the most important variable to be optimized to guarantee better environmental performances of biobased polyurethane rigid foams for thermal insulation. Care should be taken with reference to ozone depletion potential, marine eutrophication, and abiotic depletion potential because of the uncertainty related to their results. The methylene diphenyl diisocyanate and foam production process were identified as the major sources of impacts. Overall environmental superiority of biobased polyurethanes cannot always be claimed with respect to their fossil counterpart.