Huge volumes of waste building materials that are discarded every year could be recycled into new products such as gas masks and sports equipment following research being conducted by scientists and recycling firms.
Dr. Kenny Vanreppelen, a renewable product researcher and founder of Belgian start-up Act&Sorb, set up the FibreCarb project to recycle waste fibreboard after becoming frustrated at being unable to recycle the material he ripped out while renovating his house.
‘At the end of the building or renovating you probably have fibreboard as waste and, at this point, it’s not recyclable—it’s only burnt or landfilled,’ explained Dr. Vanreppelen. ‘But we’ve developed a process to use it to make a product called activated carbon, which is used as a filter in water purifiers or gas masks.’
Waste from the construction industry accounts for around half of the 1.3 billion tonnes of solid waste that cities produce globally every year. This is roughly equivalent to the amount of material inside 4.5 million single-storey homes – enough to house almost the entire population of Belgium.
Extracting raw materials and manufacturing new products for buildings, along with the construction itself, is also responsible for 3-6% of the world’s energy use, as well as a significant proportion of its carbon dioxide emissions.
This has led many concerned about the damage this is doing to the environment—and our economies—to look at ways of making better use of the waste that comes from the building industry.
Act&Sorb is tackling one of the biggest culprits—medium-density fibreboard, or MDF, which is commonly used in the walls of buildings and in flat-pack furniture.
MDF is largely made from otherwise unusable wood fibres produced as a byproduct of milling, which are combined with resin and wax, heated and pressed together. However, the glues used in binding make them difficult to recycle after use.
Carbonisation
The process developed by Act&Sorb uses a method known as carbonisation to heat the MDF to high-temperatures in the absence of oxygen, which causes it to break down into char and gas. The char is then heated further and processed according to customer specifications to create bespoke activated carbon.
According to Dr. Vanreppelen, Europe throws away 11 million tonnes of fibreboard every year while, worldwide, more than 70 million tonnes are discarded. But making this waste useful is not just environmentally compelling: it currently costs around €50 to send one tonne of fibreboard to landfill, and the vast majority of MDF is dumped in this way.
On top of the reduction in waste going into the environment and the financial benefits this brings, the market for activated carbon is also booming.
But Dr. Vanreppelen said that the environmental benefits can go beyond decreasing landfill waste. The gas produced during the pyrolysis stage, when the material is being broken down at a high temperature, can be captured and used to power the process, removing the need to use fossil fuels. Using MDF and other forms of waste chipboard also reduces the number of trees cut down to supply the wood that is commonly used to make activated carbon.
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