Environmental and economic impacts of combining backfill materials for novel circular narrow trenches

Over the last few years, several policies and new technological solutions have targeted the construction sector with the aim of reducing the sector's impacts on the environment. Among the different technological advances proposed, the reuse of materials in construction has been reported as a promising solution for an increase in sustainability and circularity. In particular, a type of cities' undergrounds assets for which materials' reuse is being explored are trenches for protecting services (i.e., water and gas transport pipelines, and optic fibre and other telecommunications services). Nonetheless, the economic and environmental benefits and impact of this type of system is still insufficiently quantified. In this research study, the economic and environmental impacts of four scenarios of trenches were assessed by using Life Cycle Costing (LCC) and Life Cycle Assessment (LCA). The four alternatives analysed consisted of: (1) the classical solution; (2) the classical solution with the reuse of soil; (3) the control low-strength material, and (4) the eco-trench. The results allowed concluding that in the eco-trench system, for which all material is reused, the environmental and economic impacts could be reduced by more than 80% and 50%, respectively. A parametric study for which the dimensions of the trenches were varied, permitted to reinforce these results and to quantify the impact's change along with the width and depth of the trench. Overall, this study provides a comprehensive view of the high-impact potential of reusing material for the construction of trenches in cities. The outcomes allow also remarking that the eco-trench system could be an attractive and advantageous solution for urban infrastructure stakeholders, both from an economic and environmental perspective

Lessons, narratives, and research directions for a sustainable circular economy

The current enthusiasm for the circular economy (CE) offers a unique opportunity to advance the impact of research on sustainability transitions. Diverse interpretations of CE by scholars, however, produce partly opposing assessments of its potential benefits, which can hinder progress. Here, we synthesize policy-relevant lessons and research directions for a sustainable CE and identify three narratives—optimist, reformist, and skeptical—that underpin the ambiguity in CE assessments. Based on 54 key CE scholars’ insights, we identify three research needs: the articulation and discussion of ontologically distinct CE narratives; bridging of technical, managerial, socio-economic, environmental, and political CE perspectives; and critical assessment of opportunities and limits of CE science–policy interactions. Our findings offer practical guidance for scholars to engage reflexively with the rapid expansion of CE knowledge, identify and pursue high-impact research directions, and communicate more effectively with practitioners and policymakers

Environmental and economic impacts of combining backfill materials for novel circular narrow trenches

Unidad de excelencia María de Maeztu CEX2019-000940-MOver the last few years, several policies and new technological solutions have targeted the construction sector with the aim of reducing the sector's impacts on the environment. Among the different technological advances proposed, the reuse of materials in construction has been reported as a promising solution for an increase in sustainability and circularity. In particular, a type of cities' undergrounds assets for which materials' reuse is being explored are trenches for protecting services (i.e., water and gas transport pipelines, and optic fibre and other telecommunications services). Nonetheless, the economic and environmental benefits and impact of this type of system is still insufficiently quantified. In this research study, the economic and environmental impacts of four scenarios of trenches were assessed by using Life Cycle Costing (LCC) and Life Cycle Assessment (LCA). The four alternatives analysed consisted of: (1) the classical solution; (2) the classical solution with the reuse of soil; (3) thecontrol low-strength material, and (4) the eco-trench. The results allowed concluding that in the eco-trench system, for which all material is reused, the environmental and economic impacts could be reduced by more than 80% and 50%, respectively. A parametric study for which the dimensions of the trenches were varied, permitted to reinforce these results and to quantify the impact's change along with the width and depth of the trench. Overall, this study provides a comprehensive view of the high-impact potential of reusing material for the construction of trenches in cities. The outcomes allow also remarking that the eco-trench system could be an attractive and advantageous solution for urban infrastructure stakeholders, both from an economic and environmental perspective

Environmental assessment of stormwater infrastructures built with the best management practices

Although some infrastructures were built for environmental purposes, there is a growing concern about their actual environmental impacts. In the context of hydrologic risk management, Best Management Practices (BMPs) are compensatory techniques in urban drainage based on physical processes for the temporary storage or infiltration of stormwater. The environmental burdens taking place in the different life-cycle stages of a service, i.e., raw materials extraction, construction, transportation, use and maintenance and end-of-life can be estimated, analysed and discussed following the Life Cycle Assessment (LCA) methodology. The objective of this study is to apply LCA to quantify the environmental impacts of the implementation of new flood prevention systems, based on the BMPs. In this case, the infiltration system consists of a grass filter, swale and infiltration trench (FST) located in São Carlos (São Paulo, Brazil). After conducting the impact assessment, an estimated carbon footprint of 1.5·104 kg of CO2eq was obtained, considering a lifespan of 10 years and a runoff storage capacity of 110 m3. The main contributors to this impact are the infiltration trench and the grass layer that covers the entire surface of the system. To the authors’ knowledge, no other studies have analysed the environmental impacts of an FST from a life-cycle perspective. Therefore, future studies should work towards the assessment of the net environmental benefits (i.e., the burdens and the benefits) resulting from the implementation of this type of infrastructure

Environmental assessment of stormwater infrastructures built with the best management practices

Although some infrastructures were built for environmental purposes, there is a growing concern about their actual environmental impacts. In the context of hydrologic risk management, Best Management Practices (BMPs) are compensatory techniques in urban drainage based on physical processes for the temporary storage or infiltration of stormwater. The environmental burdens taking place in the different life-cycle stages of a service, i.e., raw materials extraction, construction, transportation, use and maintenance and end-of-life can be estimated, analysed and discussed following the Life Cycle Assessment (LCA) methodology. The objective of this study is to apply LCA to quantify the environmental impacts of the implementation of new flood prevention systems, based on the BMPs. In this case, the infiltration system consists of a grass filter, swale and infiltration trench (FST) located in São Carlos (São Paulo, Brazil). After conducting the impact assessment, an estimated carbon footprint of 1.5·104 kg of CO2eq was obtained, considering a lifespan of 10 years and a runoff storage capacity of 110 m3. The main contributors to this impact are the infiltration trench and the grass layer that covers the entire surface of the system. To the authors’ knowledge, no other studies have analysed the environmental impacts of an FST from a life-cycle perspective. Therefore, future studies should work towards the assessment of the net environmental benefits (i.e., the burdens and the benefits) resulting from the implementation of this type of infrastructure.Postprint (published version

Environmental assessment of stormwater infrastructures built with the best management practices

Although some infrastructures were built for environmental purposes, there is a growing concern about their actual environmental impacts. In the context of hydrologic risk management, Best Management Practices (BMPs) are compensatory techniques in urban drainage based on physical processes for the temporary storage or infiltration of stormwater. The environmental burdens taking place in the different life-cycle stages of a service, i.e., raw materials extraction, construction, transportation, use and maintenance and end-of-life can be estimated, analysed and discussed following the Life Cycle Assessment (LCA) methodology. The objective of this study is to apply LCA to quantify the environmental impacts of the implementation of new flood prevention systems, based on the BMPs. In this case, the infiltration system consists of a grass filter, swale and infiltration trench (FST) located in São Carlos (São Paulo, Brazil). After conducting the impact assessment, an estimated carbon footprint of 1.5·104 kg of CO2eq was obtained, considering a lifespan of 10 years and a runoff storage capacity of 110 m3. The main contributors to this impact are the infiltration trench and the grass layer that covers the entire surface of the system. To the authors’ knowledge, no other studies have analysed the environmental impacts of an FST from a life-cycle perspective. Therefore, future studies should work towards the assessment of the net environmental benefits (i.e., the burdens and the benefits) resulting from the implementation of this type of infrastructure