PET bottles produced from polyethylene, a kind of plastic, are used in various containers such as juice, tea, soda, seasoning, and alcohol. PET is difficult to decompose by the force of nature, and the vast amount of plastic waste generated by the consumption of plastic containers is a problem. However, among these, the research results that investigated the most eco-friendly plastic bottle capacity are published in the scientific journal Scientific Reports.
Although PET bottles are known as recyclable materials, in fact, not all discarded PET bottles are recycled, but a significant amount is sent to landfills every year. According to the US Environmental Protection Agency’s EPA estimate, only 29.1% of PET bottles are recycled in the US, with the remaining 70% going to landfill.
Plastic waste, including PET bottles, has a serious impact on the global environment, so many scientists are doing their best to solve the problem of plastic waste. A research team at the University of South Carolina believes that reduction in PET waste can be realized by maximizing the content of PET bottles per PET used, and conducted a study to calculate the size of the largest capacity per weight by measuring the weights of PET bottles of various sizes.
The research team collected 187 PET bottles of various capacities sold by alcoholic beverage brands and measured the weight of PET used by a specific bottle. As a result of the measurement, it was found that small bottles of less than 473ml had a heavier PET weight per capacity than medium bottles of 473∼2,957ml or large bottles of 2,957ml or larger. In addition, the lightest PET per capacity bottle capacity was found to be 2.3 liters.
Regarding this result, the research team pointed out that the basic design of the PET bottle is related. All PET bottles have a common mechanism around the cap, and the weight of this part is almost constant regardless of the total capacity. Since the drink itself is not included in this part, it is explained that small bottles generally weigh more per capacity than large ones. In addition, it is said that the medium bottle is more efficient than a larger bottle because the shape of the plastic bottle changes to withstand the weight when it becomes a large bottle.
In addition, as factors that determine the weight of PET bottles, 80% of the capacity and 16% of the product category are involved, and the PET usage per capacity is said to be the highest in the order of juice, soda, and non-carbonated beverages. The research team also compared PET bottled beverage sales and PET waste by analyzing data from Minnesota, where the state collects and discloses PET waste, and the consumption of PET bottled beverages is close to the US average. As a result, it was confirmed that the amount of PET waste tends to be low during the period when the sales of intermediate bottles are high, and the amount of PET waste is high during the period when the sales of small bottles are collapsed.
Using national data on PET waste, the research team simulated how much PET waste could be reduced over one year under a scenario where 20% of small bottle sales went to medium bottles. As a result, it is possible that PET waste can be reduced by 9,000 tons per year just by converting small bottle sales into medium bottle sales.
Recently, public health authorities are considering reducing the size of plastic bottles, considering that excessive sugar intake is eroding health. However, the results of this study suggest that if the consumption of small plastic bottles increases, the impact on the global environment increases, and a solution that considers the future global environment is needed. Related information can be found here.