Innovation September-October 2023

F E A T U R E

The research is especially valuable since used plastic bottles and textiles are posing an increasing problem for landfills worldwide. In 1950, the world produced two million tonnes of plastics. Since then, annual production has proliferated, with 460 million tonnes produced in 2019. Small plastic particles have been found in water, air, and soil, as well as animals and people, and evidence shows microplastic pollution causes physical harm.

In addition to the many tons of plastic waste, landfills also get soil from various construction sites that takes up a lot of area. Finding a way to combine soil and plastic usefully could be key to future waste management. Different soils and clays create a different chemical reaction. Siddiqua and doctoral student Alok Chandra are researching and testing these reactions in UBCO’s advanced geomaterials research Lab.

“Our results show great potential, but there is still some work to be done before we will integrate the PET waste into landfill soil stabilization management,” says Chandra. Their study suggests the reused material strengthens the soil and serves as a water-resistant layer that will keep pollutants, such as lead, from escaping the landfill. But before adding plastic waste to soil, researchers are working to understand the environmental effects on how disintegrated plastic particles migrate underground. Currently, laboratory-scale experiments are underway to understand how plastics break down in the presence of micro-organisms, chemicals, and low temperature treatments. “I hope to see a pilot project at landfill facilities in the near future,” says Siddiqua. “This not only solves the solid waste problem but also increases the economic value of waste and encourages its re-circulation back from already polluted lands and oceans,” says Siddiqua. The research is published in the journal Waste Management ( pubmed.ncbi.nlm.nih. gov/37210958/ ). The discovery goes beyond just landfills. In the future, plastic waste could be used to build roads, driveways, and bicycle lanes. “It’s exciting,” she says. “You can develop refabricated bricks made out of natural soil and also plastic waste.” Siddiqua says PET—commonly used in containers for food and liquids—could soon be used as an additive to clay or soil to create materials for large-scale construction, although it’s currently limited when it comes to its ability to support heavy weight. The breakthrough would help to create a circular lifecycle for the ubiquitous thermoplastic polymer resin.

PhD students Maryam Firouzi, left, and Babalar Mahmoud work in the Advanced Geomaterial Research Lab at UBCO. P hoto : S am C harles , UBCO S chool of E ngineering

3 4

S E P T E M B E R / O C T O B E R 2 0 2 3

I N N O V A T I O N