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Landfill mulls cement solution for plastic waste

Roseridge ponders waste-to-energy deal

A new plan in the works at St. Albert’s landfill could one day see the city’s plastic waste burned to help make cement.

Roseridge landfill manager Gerard Duffy told the Gazette this week the landfill is looking into a plan to send the Sturgeon County region’s plastic waste to an area cement plant to be burned as fuel.

Roseridge (which takes St. Albert’s trash) is seeking out new ways to handle its plastic waste due to China’s new rules on recycling, which has barred many forms of plastic waste from its shores, said Morinville Coun. Stephen Dafoe, who sits on the landfill’s board. The new rules have prompted recyclers to tighten up what they accept in curbside recycling programs and frustrated many residents.

“If people get too frustrated with recycling, they’ll just start throwing it in the garbage,” he said, and the more waste that goes to the landfill, the quicker it fills up.

Duffy said he was approached by a group last month that proposed to have the landfill shred its plastic waste and ship it to a local cement plant, which would use it to fire its kilns. This process could accept all forms of plastic, even currently unmarketable ones like plastic clamshells and thin films.

Duffy emphasized the proposal is in its very early stages, and he isn’t sure if it is even feasible. The big question is the fuel requirement – the cement plant wanted about 60,000 tonnes of plastic per year.

“Sixty thousand tonnes of plastic is quite a bit for Roseridge to come up with,” he said, and he has yet run the idea past area governments.

Duffy said he isn’t sure if this process would throw all plastics in the kiln or just the unmarketable ones. He hasn’t figured out the cost, but said it would likely be cheaper than recycling.

“The cost to recycle plastic just keeps going up,” he said.

“If we can put all the plastic in one drum and take care of it, it would definitely alleviate some pressure off our residents.”

Dafoe said the board would get an update on this proposal later this month and would consider it in detail come March.

Greener cement

Duffy said Lehigh Cement’s Delta, B.C., operation has a similar waste-to-energy setup to the one under consideration at Roseridge.

That plant takes in tens of thousands of tonnes of wood waste and non-recyclable plastic per year to replace coal burned during cement production, said Jasper van de Wetering, alternative resources and CO2 mitigation manager for Lehigh. This change was made in part in response to the province’s carbon tax.

The cement industry creates about eight per cent of global greenhouse gas emissions, reports Carbon Brief – more than any nation besides China and the U.S. About half of that comes from heating limestone to make clinker (an ingredient in cement), while some 40 per cent comes from the fuel used to make that heat. The rest is from mining and transportation fuel.

van de Wetering said alternative fuels like waste can cut a cement plant’s fuel-related carbon footprint by as much as half, depending on the mix and amount of waste used, and help municipalities keep waste out of the landfill. The chemical reactions in cement production also trap many of the pollutants released by burning plastic in the cement itself.

Lehigh hopes to get about 35 per cent of the heat at its cement plants from waste by 2030, van de Wetering said. Lafarge got a $10 million grant from the Alberta government this week to support waste-to-energy at its Exshaw cement plant.

“The issue is establishing that supply chain,” van de Wetering said – you need about 100,000 tonnes of mixed waste to meet half a cement plant’s heating needs, and it all has to be shredded to the right size. Having a landfill that could provide such waste would help.

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