Are Plastic-coated and Compostable Paper Cups the Same?
When left in landfills, compostable paper cups can eventually be turned into garden manure. These cups contain a paper board with a PLA film coating that decomposes just like any other organic substance. In a home compost pile, it can take 90 days for a cup to decompose completely. The film coating is also biodegradable, and is made of polylactic acid. The biodegradability of PLA makes it a great alternative to petroleum-based plastics.
Although the cups themselves are made of 100% paper, the lids are still a piece of plastic that has to be removed from them. This prevents the cup from getting soggy, and is considered a contaminant by traditional recycling plants. Regardless of how many cups are used, these lids can cause problems when it comes to recycling. And even if they are recycled, their lids must be thrown away separately.
While it is possible to manufacture compostable paper cups without plastic lining, this method is not sustainable and poses serious health risks. Plastic liner can also be very difficult to compost, as most recycling facilities do not have the equipment to separate it mechanically. In addition, the polyethylene coating makes it difficult to decompose the paper portion, as it breaks down into large flakes and clogs fine pulping screens.
The main disadvantage of non-biodegradable paper cups is that they are not compostable, making them more likely to land in landfill sites. The coatings used by most of these cups are made of Polyethene, otherwise known as polyethylene, which can last up to 500 years. Even worse, the thin coating can break down into small pieces that can enter the food chain. This is an unacceptable level of waste for a product that is used in our society.