Recycling Plasterboard


Was reading about a New Zealand company, Winstone Wallboards, who were looking at the resource recovery of their waste plasterboard via compost into a soil conditioning product, and then remembered how an Australian building giant CSR were once recycling clean plasterboard from building sites for use in new production. And it got me to thinking, what is happening with this stuff. Plasterboard, also known variously as gypsum board, drywall or wallboard is basically powered gypsum minerals (calcium sulfate dihydrate) mixed in a water slurry, dried and stuck between two sheet of thick paper (often post-consumer, recycled newsprint.) It is used extensively for interior walls and ceiling. And we mean extensively. Over 80 billion square feet of the stuff per year globally, and roughly 30 billion square feet (2.8 billion square metres) of that manufactured annually in North America. Much of which is subsequently wasted. Depending on the style of house, plasterboard can make up 13% to 20% of new house construction waste. And according to some, "on an average day 40,000 tons of gypsum waste (equivalent to 40,000 cars) is being landfilled around the globe. Every day. 365 days a year." Gypsum plasterboard is a pretty benign product environmentally (if one looks past the mining extraction and C02 emitted in transporting its heavy weight about the place), particularly with regard to toxins. But it seems this might change when it meets organic waste and rain in some landfill sites. Apparently tests have indicated that hydrogen sulfide gasses can then develop. To the point that landfill bans are being considered in the EU and Canada. But solutions may be at hand.Gypsum Recycling International have developed a system of plasterboard recycling that they have rolled out across Denmark, Sweden, Norway, The Netherlands, United Kingdom, Ireland and more recently the US. They claim they can capture 94% of the board as gypsum for use as a feedstock for new production, displacing the need for up to 25% extra new raw materials. The remaining 6% waste, the paper substrate, is sent off for use in composting, heat generation and other building materials. But none of it goes to landfill. Their mobile recycling units can be transported to building or demolition sites, and have been developed to cope with contaminates like nails and screws.

Where such cradle to cradle recycling is not available, it is great to see that at least the waste gypsum is put to good use breaking up clay rich soils, via products such as offered by the Envirofert products back in NZ, LimePlus in Australia or investigated in the UK and the US, though there is some concern about additives that might've joined the gypsum at the manufacturing stage.

Thought process stimulated by Waste Streams magazine.

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