From landfill to buildings: Why organic waste is a material of the future
Katie Camero | 19 October 2017
The future could be buildings made out of mushrooms, powered by algae and fitted out with biocomposite materials, according to Arup’s latest report.
The construction industry is still using high impact materials, non-reversible building solutions and low efficiency processes and manufacturing that are releasing methane and leachates. The Urban Bio-Loop: Growing, Making and Regenerating says development and use of organic materials in the construction industry is therefore necessary for a sustainable future, imploring architects and engineers to get onboard.
Using alternative materials in construction would not only lower CO2 content, reducing health risks and costs, but also add financial value for companies and lead the development of new technologies to increase the quality of bio-based products.
“It is time to move beyond the worn out make-use-dispose models in our sector,” Arup director for global management consulting Carol Lemmens said.
“We have the ambition, capabilities and mind-set to decouple economic growth from resources consumption.”
Organic waste accumulates in cities as food and in the urban environment as biological waste coming from parks, trees, urban agricultural systems and green roofs.
Of the approximate 19 million tonnes of organic waste generated in Australia a year, only about six million tonnes is recycled, winding up in landfills. This releases more CO2 into the air than does incineration and composition, the Arup study showed.
If organic waste were turned into a source of value, it could be repurposed or remanufactured, and its components could be returned to the biosphere at the end of its engineering service life, creating more value at the environmental and economic level.
The study showed that a kilogram of waste material used for construction would offer higher economic value, about six times the value generated from energy recovery.
A kilogram of waste incinerated for energy recovery would have a commercial price of about of 0.85 €/kg (AU$U1.28). However, the same material used, as an example, for interior cladding would have a selling price somewhere between 5-6 €/kg (about AU$7-9).
“We have a fantastic opportunity to both sequester carbon and reduce waste by using more biological material in construction. We must capitalise on this opportunity by developing suitable materials and putting them into production,” Arup fellow and deputy chairman Tristram Carfrae said.
Arup researchers reported that a shift from a linear, disposal model to a circular model could produce more economic and environmental benefits because raw materials would continue to be used instead of thrown away.
The more loops natural construction products make in their service life, the more their life is prolonged, generating more value.
A circular economy, one in which natural waste is the main resource, could identify new business models to enable alternative uses of organic waste streams. This in turn could also support local and rural economies, benefitting current and future stakeholders, the study showed.
Business and innovation opportunities
The study detailed potential business opportunities that could grow around availability of organic waste, including:
- Tools to control the waste streams through the value chain so that the added value can be identified and captured.
- New manufacturing and re-manufacturing processes for reuse and recycle of natural products within the value chain.
- Creation of services to shift from selling products to selling product-service systems. These would fit particularly well for natural products with a rather limited service life such as those applied for buildings interiors.
- Enhanced collaboration within the supply chain.
Realising the value organic waste acquires through technical exploitation, investors could finance the development of new business opportunities. Alternative sources of construction products could also benefit new start-up companies, as well as SMEs, willing to invest in the valuable circular economy.
The recent use of algae and mushrooms in building products has helped architects and engineers grasp the value of natural resources, and building applications such as interior partitions, furniture, acoustic absorption and thermal insulation can all be produced by organic waste materials.
Natural products can also enhance and create new urban farming methods and technologies that could introduce a multibillion-dollar sector of development for the future. However, risk mitigation is necessary for investors who might need help from financial institutions to finance new ventures in the field of organic waste, which can often be inconsistent and limited.
There are some limitations
Reusing organic waste for construction purposes is a global opportunity but is limited by a country’s geography, climate and socioeconomic status.
Climate and seasonal constraints impact the specific number of crops that could be used for production, which could influence the opportunities for exploitation of organic waste, the study reported.
Regional circumstances as well impact the materials that end up in organic waste. Australia, for example, is currently using pineapple, sugarcane and seeds as alternative resources, according to the study, but these products are limited during specific times of the year.
Manufacturing processes also depend on location. This can affect waste collection processes that determine the quality and amount of waste recycled. For example, cities like Melbourne and London have many green areas and parks that could serve as important sources of waste, but they tend to recycle less.
Other limitations include the ability to reintroduce products into the biological loop because of chemical contamination after their service life, and local regulations that might impact the use of wastes as a feedstock.