From waste to wealth: Urban Mining put into practice

Urban  Mining  is  revolutionizing  the  way  we  think  about waste  and  resources. This innovative  approach  involves  extracting  valuable  materials from  existing  buildings  and  infrastructure,  turning  cities  into  repositories  of  reusable resources. Back in 2019, the Brussels Capital Region adopted ambitious circular economy policies, making demolition in the region not allowed unless there is a good Urban Mining plan for it. Two impressive towers in Brussels showcase the potential of the approach:
the ZIN project and the Multi tower. The ZIN project, developed by Befimmo, is one of the largest Urban Mining projects in Europe, spanning over 110,000 m². The Multi tower,developed by Immobel and Whitewood, is a 44,000 m², 18-floor project that stands out as a model of modern urban development and the first CO2 neutral office building in the city. Drees & Sommer, a global consulting company renowned for its innovative solutions in the real estate, industrial, energy, and infrastructure sectors, and its subsidiary EPEA,an  international  innovation  partner  for  environmentally  friendly  products,  processes,buildings and urban districts, have provided Cradle to Cradle consulting and supported the implementation of circular economy principles in these projects.

Out of sight, out of mind – this phrase aptly describes how we usually treat waste, including the largest current source of it: the demolition of buildings. Today, most building materials end up in landfills, where they are either destroyed or downcycled into products of much lower value. This results in a significant loss of valuable resources. Our resources are finite,and with the growing pressures of urbanization and increasing populations, it is predicted that global demand for materials will triple by 2050. In the EU alone, more than 450 million tons of construction and demolition waste are generated annually.
Michael Moradiellos del Molino, International Head of Sustainability and Circularity, Drees& Sommer: "We need to move away from the mindset of demolition and instead identify and review the existing materials in our buildings. Our cities are dynamic, manmade stock with a unique metabolism, and we are surrounded by more than 50 billion tons of valuable materials.”
Urban  Mining  addresses  the  critical  issue  of  finite  resources,  complementing  Cradle  to Cradle  (C2C)  principles  and  supporting  the  circular  economy. Brussels  is  home  to  two projects that highlight the potential of the concept: the ZIN project and the Multi Tower. Both  have  been  supported  by  Drees  &  Sommer and  EPEA in the  integration  of  circular economy specifications.

ZIN Project: A Landmark in Urban Mining and Circular Economy

The  "ZIN"  project,  developed  by the  Belgian  real  estate  investment  trust "Befimmo",consists of the renovation of towers 1 and 2 of the Brussels World Trade Center. After the dismantling process, the existing towers were joined by a new section featuring 14 double-height  floors. The  multifunctional  space  of  the  ZIN accommodates offices,  co-working spaces, housing and hotel services on 110,000 m². It was designed by architects Jaspers &Eyers/51N4E/AUC, and reaches a  height  of  around  100 meters. The  main  part,  covering 75,000 m² is for office space use and includes a co-working area. In February 2024, the first entities  of  the  Flemish  government moved into  their  new  office  building  (the  Marie-Elisabeth  Belpaire  Building),  which  is  part  of  the  ZIN  project. A  further  14,000 m²  is  for apartments  and  16,000 m² for hotel  accommodations,  leisure  areas,  restaurants,  and shops.

One  of  the main ambitions  of  this  project  has  been  to  integrate  the Cradle  to  Cradle thinking, through the inventory and reuse of a maximum of materials as well as the Cradle to  Cradle Certified® certification of  dozens  of  building  materials. Over 1.000  tons  of materials, including raised floor, partition, insulation and roof tiles, have been reused, and 140 tons upcycled. Drees & Sommer and EPEA have supported this project with Cradle to Cradle  consulting,  including  the  identification  of  available  materials  and  solutions,demolition support according to C2C, and the implementation of the Material Passport.

Wim Plaum, Project Director at Befimmo: “We know that the future of construction is not just about putting one brick on top of another. It’s about doing it better—for the people,and  for  the  planet  that  supports  us  all.  That’s  why  we’re  determined  to  reshape  the industry, with sustainability at the center of everything we do.

We strive to set new standards that go beyond the expected. By working closely with our partners  and  subcontractors,  we  challenge  them  to  achieve  Cradle  to  Cradle  (C2C)certification, because real progress comes when we all move in the same direction.
And  we  don’t  stop  there.  We  focus  on  reusing  materials  on-site  through  urban  mining,ensuring every project feeds into a circular economy. This is how we make our shared vision real—by creating a future that is sustainable, practical, and responsible."
Examples of successful collaboration with partners and subcontractors include sustainable and  circular  waterproofing  of  approximately  50,000  m2 by Derbigum, circular  doors developed specifically for ZIN by Eribel, and Cradle to Cradle Certified aluminium facade outlines by  Kyotec  Group. Additionally, CCB  Concrete  transformed 30,000  tons  of  old concrete from the WTC towers into high-quality, Cradle to Cradle Certified® Silver circular concrete,  which  was  reused  as  a  full  load-bearing  floor  slab  in  the  ZIN  reconstruction,marking the first time this has been done in the Benelux region.

Multi tower’s multi-sustainability strengths

Following its renovation, this significant project by Immobel and Whitewood, who acquired the  building  in  late  2015,  now  provides  approximately  44,000  m²  of  office  space accommodating  2,000  people,  along  with  retail  units.  The  project  has  earned  BREEAM“Excellent”  certification,  placing  it  among  the  top  10%  of  new  commercial  buildings  in Belgium.

This  is  another  urban  mining  monitoring  project  that  Drees  &  Sommer supported with Building Circularity Passport and  Urban  Mining passport  services. In Multi, 89%  of  the existing concrete has been reused, saving 3,259 tons of embodied carbon, 20,000 tons of waste, 2,222  cement  trucks and 2,000  cement  truck  journeys. The  building  boasts  the highest percentage of reused materials among large-scale office projects in Brussels, with 3% sourced through urban mining of iconic Belgian locations, in cooperation with circularity partner  Rotor  DC. Thanks  to  its  energy  and  carbon  performance,  as  well  as its circular economy  credentials, the  French  group TOTAL and  Bpost, Belgium’s  leading  postal operator, have chosen to rent the building.

Valérie Vermandel, Chief Development Officer at Whitewood: "The transformation of the Multi Tower is a testament to our commitment to sustainability and innovation. By turning what was once a dark, heavy structure into a bright, multi-functional workspace, we have not only revitalized the building but also set a new standard for urban development. The Multi tower showcases our dedication to circularity and environmental responsibility."

Laurent Withofs, Project manager at Whitewood: “With renovations you can run into a lot more obstacles  than you would with a  new  build. Old  materials  can  house  asbestos,  for example,  which  is  a  problem  that  needs  to  be  properly  dealt  with  before  we  can  safely continue with a project. A new build wouldn’t have those issues. This is why I am especially excited to show what we can do to transform old buildings that have gone out of fashion when we think critically and get the right people involved.”

Towards a Regenerative Future

Hein van Tuijl, Managing Director of EPEA Benelux: "Beyond the obvious ecological perks,considering the built environment as a repository of resources can save money and improve health. Our Circularity Passports® provide detailed information on each material’s chemical composition, enabling the use of non-toxic materials in construction and eliminating health risks at each stage of the circular material use.”

Since the inception of the EU-funded research project Buildings As Material Banks in 2015,EPEA has issued hundreds of passports, continuously refining them to promote the circular use  of  materials  in  construction. It  is  important  to  emphasize  that the  Cradle  to  Cradle approach  differs  from  traditional  recycling,  which  often  includes  downcycling  or  energy recovery methods that are detrimental to climate protection and resource conservation.

The Circularity Passport® describes the value of materials for circular use, including their ability to be separated, deconstructed, and reused during conversion or demolition, thus transforming  buildings  into  valuable  repositories  of  raw  materials.  This  passport also includes carbon  footprints,  including  the “grey energy” from  the  production,  transport,deconstruction,  and  disposal  of  building  materials,  providing  a  comprehensive  life  cycle assessment. This tool aims to pro-actively inform stakeholders about how to select the right materials and how to apply them in a circular way.