Innovation September-October 2023

What’s the potential process to use plastic bottles to stabilize landfills? Solvent-based depolymerization of plastic bottles is one of the innovative ways to solve this crisis. To remove impurities, a selective solvent dissolution process is used to recover plastics of minimum standards suitable for reuse. The pure polymer can be extracted from the solution through precipitation such as BHET (Bis 2-Hydroxyethyl terephthalate). The application of PET waste into soil is direct, and one needs only to pre-process the waste into finer (micron-sized) grains. Are there other types of waste this could work with? Plastic waste, including low-density polyethene (LDPE), polypropylene (PP), polyvinyl chloride (PVC), and polyethene terephthalate (PET), has already been used as a filler or as an admixture in the concrete paste and asphalts for road pavement design. Plastic waste holds several key Q&A WITH DR. SUMI SIDDIQUA

chemical complexes that can react and bind with various industrial waste, for example pulp mill fly ash and biochar. What are some of the challenges to adoption? In Canada, most of the plastics are produced from virgin resins, so the plastic waste generated in Canada enters landfills. The most significant challenge is establishing a circular economy potential for this plastic waste so that its value would be recovered at the end of its useful life. In this way, plastic waste can be applied in a large-scale construction market, extending its life cycle and reducing adverse environmental impacts. Are there other projects by grad students exploring how to improve landfills and waste management? Two of the master’s degree students in the Advanced Geomaterials Research Lab are looking into the shear strength and suction properties of BHET-treated sand-bentonite

Dr. Sumi Siddiqua, P.Eng. P hoto : C ourtesy of UBCO

in the presence of biochar. The goal is to improve the strength and minimize desiccation cracks. Also, a PhD student is currently developing waste-based composites for polystyrene microplastics (MPs) adsorption. In this project, we have designed column tests set up to model contaminant (MPs) transport mechanisms in landfills.

P R O F E S S I O N A L S E R V I C E S

Adver t ising in INNOVATION

For more information: Email advertising@egbc.ca Call: Wing-Yee Kwong at 604.681.1811

I N N O V A T I O N

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

3 5