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Go Compostable or Go Home

By: Stephanie Higgins

Source: Pexels

Plastics compete in the same market, whether they are brand new (primary) or recycled (secondary). When oil costs are low, as they were in 2016, the price of primary plastic drops. Secondary plastics, on the other hand, have a more fixed price as labour costs associated with recycling remain the same, while the quality is lower. The difficulty to turn a profit has led to a decrease in environmental health as many secondary plastic producers ceased operations in 2016. With only 9% of plastics being recycled in 2016, and 86% being diverted to landfills (Figure 1), it is evident that solutions are necessary.

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Figure 1. Canadian resin flows in thousands of tonnes per annum, 2016 source: Economic Study of the Canadian Plastic Industry, Markets and Waste (2019).

In June 2019, CBC reported the Trudeau government will ban single-use plastics as early as 2021, including bags, plastic straws, cotton swabs, drink stirrers, plates, cutlery, packaging, and balloon sticks (oxo-degradable plastics), that do not fully decompose in the environment, but degrade and remain in the environment for up to 1000 years. This was announced after Prime Minister Justin Trudeau joined the Canada-led Ocean Plastics Charter last June, with many countries such as France, Germany, Italy, the U.K., and the EU signing on. 

A news release from the Trudeau Government on June 10, 2019, reads, “These measures will be grounded in scientific evidence and will align, where appropriate, with similar actions being taken in the European Union and other countries.” However, the 2030 deadline of zero plastic waste is called “ambitious” and that “business-as-usual or incremental changes are not an option” in Canadian Plastic Industry, Markets and Waste (2019). They add that a Canada-wide Strategy on Zero Plastic Waste is in development which would create approximately 42,000 jobs. 

The plastics industry in Canada is booming, with $35 billion in sales, 93,000 jobs in Ontario, Quebec, and Alberta, and recycling generating $350 million and 500 jobs in less than a dozen companies.  

So, what will replace convenient, profitable, disposable single-use plastics? There are two main categories of plastic alternatives (also called bioplastics): biodegradable and compostable. Biodegradable options can be either bio- or petrochemical-based, where enzymatic breakdown by microbes releases carbon dioxide, water, inorganic compounds, and biomass. These biodegradable options can also release heavy metals, or only partially breakdown (ASTM standard D6813). 

Compostable options, on the other hand, will biodegrade at least 90% within 180 days in a facility, which is consistent with the rate of other compostable materials (cellulose) (ASTM standard D996, also D6400). Standards in the US and Europe already exist for compostable materials such that: i) they meet this standard decomposition timeline, ii) leftover compost will be free of toxins, iii) meet a regulated heavy metal concentration, and iv) lack obvious polymer residues, and so can be sold for gardening and agricultural uses. 

Some biodegradable plastics are difficult to recycle, specifically, the multilayer laminate on food packaging compromises the integrity of the biodegradable plastic if recycled, and current recycling facilities are not equipped to handle biodegradable plastics. Incineration of biodegradable and compostable plastics has been proposed as an energy source (even has no notable atmospheric pollution); however, the moisture of the waste may play a key role in determining whether this is energetically feasible. 

While there are some compostable plastics that can be composted at home (writer found no standard), poor at-home composting can lead to anaerobic (low oxygen) decomposition and methane release. Some people will not have the interest or space to compost. However, at home composting would be an excellent option, cutting down on fees associated with waste management, the ability to sell compost from facilities for agriculture or at-home  use (at a time when phosphate rock is becoming scarce, no less), and compostable plastic litter would naturally decompose in the environment – whether that is on our highways, or in our waterways. 

Technically anything is biodegradable given enough time and under specific temperature and moisture conditions – even the very plastics the Trudeau government wants to eliminate. Therefore, whatever future restrictions on single-use plastics, there should be packaging requirements so the consumer can make an informed choice. The certification standards from other countries would be a good starting point, with specific symbols clearly stating the material is “compost facility friendly”, “burn friendly”, “home compostable friendly” or “general waste only.” 

Whether recycling, composting in a facility, incinerating, or at home composting, there are benefits and drawbacks. Composting is not just a tree-hugger’s favourite past-time (I can say it, I had composting worms in my house once). Composting and incineration are two feasible and potentially profitable avenues for waste disposal. On top of that: the environment wins. With creative bioplastic solutions ready for environmental and financial success, it’s time to go big or go home. 

Sources: 

Biodegradable vs compostable vs oxo-degradable. (2020, March 30). Retrieved January 22, 2021, from https://www.greendotbioplastics.com/biodegradable-vs-compostable-vs-oxo-degradable-plastics-a-straightforward-explanation/

Canada to ban harmful single-use plastics and hold companies responsible for plastic waste. (2019, June 10). Retrieved January 22, 2021, from https://pm.gc.ca/en/news/news-releases/2019/06/10/canada-ban-harmful-single-use-plastics-and-hold-companies-responsible

Environment and Climate Change Canada. Summary Report to Environment and Climate Change Canada. (En4-366/1-2019E-PDF). Retrieved from Environment and Climate Change Canada website: http://publications.gc.ca/collections/collection_2019/eccc/En4-366-1-2019-eng.pdf

Government to ban single-use plastics as early as 2021: Source | CBC News. (2019, June 10). Retrieved January 22, 2021, from https://www.cbc.ca/news/politics/government-to-ban-single-use-plastics-as-early-as-2021-source-1.5168386

Miller, R. (2005). The landscape for biopolymers in packaging. Miller-Klein Associates report. Summary and Full Report available from The National Non-Food Crops Centre, Heslington, York, UK www. nnfcc. co. uk.

Song, J. H., Murphy, R. J., Narayan, R., & Davies, G. B. H. (2009). Biodegradable and compostable alternatives to conventional plastics. Philosophical transactions of the royal society B: Biological sciences364(1526), 2127-2139.

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