Circular economy: The way to sustainable buildings

Mayara Regina Munaro
Ph.D., Postdoctoral Student
Laboratory of Microstructure and Eco-Efficiency of Materials, Department of Civil Construction Engineering, Polytechnic School, University of Sao Paulo
Brazil

mayara.munaro@lme.pcc.usp.br

Floods, fires, hurricanes, and intense waves of cold and heat are some of the climatic events that are increasingly frequent, and their extreme effects are already permanent in the world. The climate has already changed, and it is affecting every corner of the planet and the way we live. The need to reduce the negative environmental externalities associated with the linear model of production, based on the extraction and intensive consumption of natural resources, are already central guidelines of global climate and biodiversity policies. If, on the one hand, issues such as local scarcity and unbridled demand have intensified geopolitical issues, such as economic volatility and the increase in global commodity prices, on the other hand, overexploitation and degradation of ecosystems have caused irreversible environmental impacts, such as air pollution and water, changes in ecosystems, in addition to regional scarcity, even in materials considered abundant, such as sand and gravel.

The construction sector has effectively contributed to this scenario, being the largest consumer of mineral resources in the world, responsible for high levels of waste generation, greenhouse gases (GHG), and consuming more than a third of the total energy on the planet. In addition, population growth linked to urbanization, longevity, and rising incomes has increased pressure on governments to meet housing and infrastructure demands sustainably. The fact is that construction materials and products end up being wasted when they are no longer needed for their intended function, a fact that accelerates the devastation of ecosystems and brings risks of resource scarcity.

To change the current scenario, it is necessary to use resources more efficiently and minimize the generation of construction and demolition waste (CDW). Inefficient waste management, which ranges from non-existent collection systems to environmentally incorrect disposal, in addition to involving significant losses of materials that could be reused, causes damage to public cleaning services, compromises the functioning of drainage and urban mobility, generates visual pollution, soil, water, and air contamination and is a vector for the proliferation of insects and rodents, causing infections and transmitting diseases. The environmentally correct final disposal of waste in sanitary landfills also has issues that deserve evaluation, since the costs of implementing and operating these works are high. Minimizing waste is the first step that must be taken in waste management and the design phase is crucial to avoid waste, followed by strategies to recover materials and energy from waste. Reducing the burden of landfills could reduce global GHG emissions by 10 to 15% (UNEP, 2015).

In parallel, considering that 67% of global GHG emissions are related to materials management (CIRCLE ECONOMY, 2018), mitigating climate change requires implementing circular strategies and solutions to address the linear use of materials and energy. Decoupling the extraction and use of natural resources from current production and consumption patterns can be one of the most economical and effective ways to reduce impacts on the environment and promote human well-being. Efficient use of resources can be achieved by different strategies, such as dematerialization; more durable products; more intense use; product upgrade, modularization, remanufacturing; and reuse of components. For this, the focus becomes the design stage, which should emphasize strategies that optimize the performance of the specified materials and promote the closure of material cycles, through maintenance, reuse, remanufacturing, renovation, and/or recycling.

The circularity of resources and construction products must cover all stages of the life cycle of buildings and the building must be designed and consumed as a dynamic, flexible object that evolves and adapts according to the needs of users. The focus is on building better. An efficient housing project, in addition to the efficient use of materials and minimizing the number of materials needed for construction, must prioritize the adaptability of spaces. Strategies such as modular construction, use of local materials, use of more efficient materials, use of secondary materials, and design for deconstruction should be an integral part of the projects. Furthermore, it is not just the quantity of inventory that matters, but more importantly, its quality, as better buildings and infrastructure will last longer, require less maintenance, and serve users’ needs longer, resulting in an overall reduction in the load for the environment.

Adopting the circular economy is a prerequisite for more sustainable buildings. The construction sector needs to evolve towards a system based on circularity, in which buildings and construction materials are used, reused, adapted, and rebuilt, considering economic and environmental rationality at the heart of decisions. For all circular business models, information and communication technology is a key enabler. It is necessary to better understand what material is available, it is quality, and when the materials become available for reuse, as well as their potential for reuse. To this end, material passports are key initiatives for documenting and tracking the circular potential of materials, products, and systems, providing guidance in choosing more sustainable materials for recovery and reuse. When scaling the circular economy, standardization of quality criteria and a common language is needed so that various initiatives can connect. Connecting systems such as digital marketplaces for Building Information Modelling (BIM), Life Cycle Assessment databases, and certifications are essential to achieve scale.

Implementation of circular practices in the construction industry is limited. The industry is conservative and has its design process, manufacturing techniques, supply chain, and financial arrangements. Furthermore, the fragmented value chain makes it difficult to share information and create industrial symbiosis. Understanding where value creation becomes circular should be the starting point for the organization or stakeholders. Policies around consumer taxation, legal frameworks, specific recycling targets, corporate accountability for products throughout the life cycle, implementation of tax premiums for the use of regenerated resources and building code regulation need to be reconsidered. There is a need for greater involvement of academia, industry, relevant stakeholders, and oversight bodies in participating in assessments to improve empirical processes and support the decision on the reuse potential of materials. This also includes understanding available indicators and technologies, from scarce resources to consumer behaviour, with a focus on closed-loop materials.

References

CIRCLE ECONOMY. (2018). The Circularity Gap report: An analysis of the circular state of the global economy.

UNEP, (2015). Global waste management outlook.

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