Filtering by
- All Subjects: circular economy
- All Subjects: urban planning
The built environment is responsible for a significant portion of global waste generation.
Construction and demolition (C&D) waste requires significant landfill areas and costs
billions of dollars. New business models that reduce this waste may prove to be financially
beneficial and generally more sustainable. One such model is referred to as the “Circular
Economy” (CE), which promotes the efficient use of materials to minimize waste
generation and raw material consumption. CE is achieved by maximizing the life of
materials and components and by reclaiming the typically wasted value at the end of their
life. This thesis identifies the potential opportunities for using CE in the built environment.
It first calculates the magnitude of C&D waste and its main streams, highlights the top
C&D materials based on weight and value using data from various regions, identifies the
top C&D materials’ current recycling and reuse rates, and finally estimates a potential
financial benefit of $3.7 billion from redirecting C&D waste using the CE concept in the
United States.
Findings indicate that the deployment of green roofs will cool the urban environment in daytime and warm it at night, via evapotranspiration and soil insulation. At the annual scale, green roofs are effective in decreasing building energy demands for both summer cooling and winter heating. For cities in arid and semiarid environments, an optimal trade-off between water and energy resources can be achieved via innovative design of smart urban irrigation schemes, enabled by meticulous analysis of the water-energy nexus. Using water-saving plants alleviates water shortage induced by population growth, but comes at the price of an exacerbated urban thermal environment. Realizing the potential water buffering capacity of urban green infrastructure is crucial for the long-term water sustainability and subsequently multisector sustainability of cities. Environmental performance of urban green infrastructure is determined by land-atmosphere interactions, geographic and meteorological conditions, and hence it is recommended that analysis should be conducted on a city-by-city basis before actual implementation of green infrastructure.
Historically, Life Cycle Assessments (LCA) guided companies to make better decisions to improve the environmental impacts of their products. However, as new Circular Economy (CE) tools emerge, the usefulness of LCA in assessing linear products grow more and more obsolete. Research Question: How do LCA-based tools account for reuse/multiple life cycles of products verses CE-based tools?
The Kaiteki Innovation Framework (KIF) was used to address the question of circularity of two packaging materials using an Environmental LCA to populate its 12 CE dimensions. Any gaps were evaluated with 2 LCA- based and 2 CE-based tools to see which could address the leftover CE dimensions.
Results showed that to complete the KIF template, LCA data required one of the LCA-based tools: Social Life Cycle Assessment (SLCA) and both CE-based tools: Circular Transition Indicators (CTI) and Material Circularity Indicator (MCI) to supplement gaps in the KIF. The LCA addressed 5 of the KIF dimensions: Innovation Category Name, Description, GHG Impact, Other Environmental Impacts, and Value Chain Position. 3 analytical tools addressed 5 more:: Effect on Circularity, Social Impacts, Enabling Technologies, Tier 2 and 3 Requirements, and Value Chain Synergies. None of the tools could address the KIF Dimensions: State of Development or Scale Requirements. All in all, the KIF required both LCA-based and CE-based tools to cover social and socio-economic impacts from a cradle-to-cradle perspective with multiple circular loops in mind. These results can help in the research and development of innovative, circular products that can lead to a more environmentally preferred future.