Cellulose residue taken from cardboard and paper waste generated at paper mills has already gone through several reuse cycles, meaning that the remaining cellulose fibres are too short to be bound together in order for it to be made into paper again. As a result, these fibres would typically end up in landfill or be burnt – a process that creates an estimated seven million tons waste globally each year.
Building material made from recycled paper sludge
Located in a waste treatment centre, in Vacarisses, Barcelona, Spain, Honext, founded in 2011, is a spin-off of the Polytechnic University of Catalunya for the industrialization of a patent process, product and application.
This transforms a residue (primary sludge) generated by the paper industry into a new cellulose-based material, sustainable, versatile, with excellent properties (reaction to fire, moisture, acoustic absorption, mechanical resistance, non-toxic) and multiple applications (construction, furniture and packaging).
The company mixes together waste cellulose fibres with water and enzymes – depending on the quality of the waste, a mixture of 50 to 75 % paper sludge and 25 to 50 % cardboard waste is used. The circular economy manufacturing process, in addition to using the sludge from paper mills as raw material, incorporates water coming from the local landfill leachate, as well as methane and electricity generated from the digestion from the town’s waste.
The Hontext factory will have an annual production capacity of 2,000 m3 of panels.
Discover Solution 187: Horses
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