Continuing the theme of biodegraded plastics that was discussed at our previous lecture on the 6th of February, I would like to add some words on the topic. The Biodegradable Products Institute and the National Geographic, a usual adviser on how to live and think green, argue that the things are not so simple as they look:

- biodegradability can be measured "by the extent to which a substance degrades through natural means and by how fast that process occurs. Unfortunately, there is no regulatory definition of the term "biodegradable" as it applies to a complete product, since the only standardized testing in place for biodegradability pertains to individual ingredients." (Taken from: Biodegradable Household Products)

- biodegradable products are not supposed to biodegrade in the landfill. "Nothing biodegrades in a landfill because nothing is supposed to." (...) "...uncontrolled biodegradation in a landfill can cause ground water pollution, methane gas emissions, and unstable sub-soil conditions. As a result, modern landfills are kept dry and air-tight to prevent biodegradation. Composting, on the other hand, is the process of controlled biodegradation outside a landfill.
By carefully controlling the feedstocks (source-separated, mixed organics), and controlling the process (moisture content, oxygen levels), composters transform biogegradable materials into useful products that are used in farming, gardening and soil conservation.

Today, despite national progress on yard waste composting, more than 60 million tons of biodegradable materials (food scraps, wet & soiled paper, leaves and grass) are still being sent to landfills where they will sit in an airless, dry environment to be mummified.

The phrase biodegradable, like recyclable, merely describes the composition of a product. Its potential, not its inherent value. If a product is sent to a landfill, and not disposed of properly in a municipal composting or recycling facility, it is still part of the problem no matter what it's made from.

(Taken from : The Myths of Biodegradation)

Read More:

What Are the Benefits of Biodegradable Plastic?