Building materials made from organic waste could help boost bio-economy

Organic waste could be used to make building materials and then fed back into the biological cycle at the end of their service life, claims a new report from Arup.

organic waste
Organic waste at landfill site

Currently managed through landfill, incineration and composting, certain forms of organic waste could be diverted to help the global construction industry reduce its use of raw materials. In the UK alone, WRAP estimates that the construction industry accounts for 60 per cent of all raw materials consumed.

Capturing organic waste streams from cities and the countryside could provide the industry with lower-cost, lower-CO2 building materials including bricks, insulation and partition boards. The report envisages a completely circular system with nutrients returned to the soil when building waste is fed back into the biological cycle.

According to Eurostat Data, over 40 million tonnes of dried organic waste from agriculture and forestry was produced in Europe in 2014, and the amount is growing year on year. A kilogram of waste incinerated for energy recovery has a value of approximately 0.85 but the same material used for interior cladding could sell for up to €6 per kilogram.

The report also points to advances in the development of alternative organic materials, including mushroom bricks grown in five days and waste potatoes used as insulation and acoustic absorbers. Innovative manufacturing processes are a significant enabler, with 3D printing of bio-polymers becoming increasingly widespread.

Guglielmo Carra, European lead for materials consulting at Arup, said: “As one of the world’s largest users of resources we need to move away from our ‘take, use, dispose’ mentality. There are already pockets of activity, with some producers making lower-CO2 building products from organic materials.

“What we need now is for the industry to come together to scale up this activity so that it enters the mainstream. An important first step is to work with government to rethink construction codes and regulations to consider waste as a resource, opening up the opportunity to repurpose it on an industrial scale.”

The report highlights the following organic matter products already available:

Peanuts: shells are being used to produce low-cost materials, such as partition boards that are resistant to moisture and flame retardant

Rice: rice husk ash can be mixed with cement to reduce the need for fillers. Rice can also be used as a raw material for the production of boards

Banana: Banana fruit and leaves are being used to make rugged textiles. Bananas contain high strength fibre and have good acoustic absorption and durability

Potato: the peel from potatoes can be cleaned, pressed and dried to create a low-weight, fire resistant, water repellent, insulating material and acoustic absorber

Arup is working on opportunities to embed circular economy principles in the built environment, working alongside the Ellen McArthur Foundation as a Knowledge Partner. In 2016 Arup installed the Circular Building, which is designed and constructed out of fully re-usable components.