Circular economy

Many natural resources are irreplaceable. We therefore need to care what happens to them from the moment they are extracted – including their transportation and processing into construction materials and products, their incorporation into buildings and infrastructure, the use, maintenance and repair of those assets, their eventual removal, and the treatment of the arising ‘wastes’.

Circularity involves keeping materials in use by sharing, leasing, adapting, reusing, repairing, refurbishing, reclaiming, remanufacturing and lastly recycling. When resources are remanufactured and recycled, a key goal is to retain – or at least minimise loss of – performance and value between first, second and tertiary uses.

Wastewater and organic solid waste are nutrient and energy rich, and for as long human society exists they will be in constant supply. Circularity involves recognising, harnessing and maximising the value that can be obtained: by treating these streams as resources for energy generation and industrial and agricultural production.

Why are we putting O&M as step number one?

In mature economies, new construction adds an estimated 0.5% per year to the value of the built environment. Seen another way, 99.5% of our buildings and infrastructure already exist.

Therefore, thinking and practice to create the circular economy should start with buildings and infrastructure in use. The best way to avoid waste is to keep existing assets and the resources embedded within them working, providing services and delivering value.

• Be digital and data-led: Use real-time data to tune the operation of mechanical equipment to changing conditions and loads; operate to minimise component wear.
• Demand the right to repair: Make repair and refurbishment the default solution in preference to demolition and replacement.
• Strengthen asset management: Build circular economy objectives, metrics and processes into your asset management strategy, planning and delivery; maintain regularly to extend the life of existing assets.
• Reuse: Gain new value from existing assets and components by rethinking their use, reconfiguring, reconditioning or remanufacturing them.
• Adapt, retrofit and refurbish: Gain value and reduce capital expenditure by extending the life of existing assets.
• Integrate: Capital delivery, asset operation and maintenance are commonly siloed disciplines – people, work processes, culture, objectives, performance metrics and incentives seldom connect. The things that make for successful construction don’t always translate into successful operation. Poorly integrated and commissioned assets often fail to attain their intended level of performance and can be a drag on the assets and systems to which they are connected. So ensure new assets are effectively integrated with existing systems to avoid any operational ‘friction’ that could impair efficiency.
• Commission: Set performance targets and make achieving and sustaining them part of procurement, so that new assets or interventions work as expected and there is no ‘back-sliding’. Ensure operational staff understand how and are fully capable of maintaining performance following final hand-over.
• Take every opportunity: Treat all interventions involving adaptation of existing assets, however minor, as an opportunity to recover resources from the built environment, returning them to the stock of available resources.

New approaches to organisational and spatial planning are both essential. Organisations right across the built environment value chain, from major clients to small suppliers, must specify circularity as a fundamental outcome – for themselves and for those they transact with. And they must arrange themselves so that materials can be traded and exchanged with maximum retained performance and value.

• Set the objective: Build circular economy principles and objectives into your organisational strategy, planning and delivery.
• Challenge need: Resource consumption can be substantially reduced by challenging and changing user behaviours. Cutting back user demand can sometimes remove the need for construction of new buildings or infrastructure altogether.
• Use nature-based solutions: Hard engineering can sometimes be minimised or avoided by using nature-based solutions. Using nature-based solutions where possible will also bring wider environmental and social benefits.
• Pursue efficiency: Further reduce the need for new construction by squeezing the maximum performance from existing assets and adapting redundant assets to new uses.
• Manage stocks and flows: View the built environment as a bank of materials that can be drawn on for resources as an alternative to first-use materials. Deliver all materials, components, assemblages and assets with digital certificates that record and track their provenance, composition, use and condition.
• Conduct lifecycle assessments: Assess the service life of assets, components and materials, and their availability, utility and value, in order to understand when resources can be released for reuse and potential trade-offs between their value in current and future uses.
• Develop the circular ecosystem: Enable the flow of resources by, for example, locating assets that produce too much heat close to assets that require heating, such as an underground station and a hospital, or an advanced anaerobic digestion facility and a commercial greenhouse. And build local ‘ecosystems’ of companies to manage stocks and flows through the ‘bank of materials’.

You’re probably familiar with DfMA – design for manufacture and assembly. The circular economy requires design for a much wider range of stages and activities including manufacture, assembly, adaptation, repurposing, repair and disassembly – design for ‘X’ or DfX.

• Employ BIM and digital twins: Use digital asset models, considering requirements at every stage of the asset lifecycle from construction to decommissioning, and to provide a platform for asset management.
• Design for reuse: Seek to keep existing assets in use, in situ and without modification. If that’s not possible, design to reuse assets in new locations with minimal modification.
• Design for longevity: Beware, this may involve using more resources initially to provide durability, climate resilience, or extra capacity to meet foreseeable changes in use. Design for through-life adaptation and refurbishment.
• Design for construction: Projects are still being delivered where up to half of the materials brought to site end up in landfill, not in the finished asset. Waste arises from designs that are difficult to build or that ignore standard dimensions and units, resulting in leftover quantities; over-ordering due to caution or uncertainty; transporting and storing unused materials; weather and accidental damage of materials in storage; poor supply chain co-ordination; and human error. All these causes of waste can be addressed by designing for modern methods of construction.
• Design for adaptation and deconstruction: Design for removal and replacement of components; for disassembly; and for easy and clean separation of materials, avoiding loss of value.
• Design for efficiency: Optimise your use of resources, saving cost and carbon by doing so; design to optimise and sustain the value of materials throughout their lifecycle – or through multiple lifecycles.
• Design for standardisation: Make it easier to integrate and disassemble assets using products and modules based on industry standards and using common platforms.

Developing the circular economy calls for new commercial approaches and relationships right across the value chain. Tender criteria and bid evaluation need to be aligned with the circular economy, with appropriate scoring, contracts and commercial incentives. Greening procurement requires clear vision and effective leadership, workforce upskilling, appropriate standards and performance metrics, and robust governance.

• Buy products as a service: Lease materials, products and components, with the supplier optimising their performance in use and taking them back when no longer needed or at end of life.
• Specify: Accept and expect asset reuse, combining recovered and reconditioned materials, components and assemblages with new ones.
• Use sustainable products and healthy materials: Demand materials and products that are recycled, reclaimed, reconditioned or regenerative – or that can be. And specify materials and products that have no harmful health or environmental impacts.
• Innovate: Pilot, scale and commercialise new products, technical solutions and ways of working.
• Collaborate: Share risk, gain from shared knowledge and experience, achieve efficiencies of scale and optimise value by procuring jointly with others in your sector.
• Employ modern methods of construction: Use offsite manufacturing, just in time delivery and onsite assembly to enable unprecedented resource-efficiency and waste reduction. In late 2022 ‘rules’ for standardising and systematising technologies were published by the Construction Innovation Hub (we co-authored them). Establishing common design approaches and interfaces will enable a shift from construction as an ad-hoc and disparate industry to mass production and integration, transforming productivity, cutting delivery risk and delivering better certainty, value and outcomes. It also supports design for reconfiguration, disassembly and reuse.
• Adapt: Employ standardised components, modules and assemblages with ‘universal’ connections that allow for adaptation as well as disassembly. For some asset types, up to 80% of construction needs can be met this way, requiring only 20% bespoke solutions to meet site-specific needs.
• Collaborate and consolidate: Developing modern methods of construction for mass production requires participation at scale: large clients need to consolidate projects into programmes; clients with similar asset requirements must seek common solutions and shared efficiencies; suppliers need to develop compatible solutions and systems.
• Recover: Treat all manufacturing and construction wastes as feedstock, aiming for minimal new resource inputs to make them usable, with little or no loss of value.
• Change behaviours: Store and manage materials to avoid wastage through damage.
• Buy responsibly: Avoid single use tools and packaging.

As the circular economy grows and becomes more sophisticated, with ever greater numbers of organisations connected into it and trading in resources, the economic, social and environmental benefits will multiply in number and value.

• Recover energy: Treat waste streams to generate electricity, heat or fuel, for example using anaerobic digestion to produce biomethane.
• Create biofertiliser: Use treated biosolids as a soil nutrient or growing medium, or compost organic waste for use in farming, landscaping or restoration.
• Buy second use materials: Trade and use recovered, reconditioned and recycled components and materials.
• Procure materials as a service: Lease products and materials, and return them when no longer required.
• Employ reverse logistics: Create supply chains to adapt, disassemble, recondition, recycle and resupply materials and products.
• Deconstruct and disassemble: Develop specialist skills and techniques that preserve the value of materials and products.
• Recycle: Process materials to maximise retained value, minimise inputs of energy, water and first-use resources, and to avoid negative externalities.