Landfill-biodegradable products are made by combining traditional plastic with an organic additive. The biodegradation only begins when the plastic is exposed to a microbe-rich environment, such as a landfill. The additive attracts microbes to the plastic and they start to digest it. As they do this, the enzymes (the microbes secrete) break the carbon bonds in the plastic molecule allowing the microbes to digest them for their energy. As more enzymes are secreted, more atoms are removed from the plastic molecule (called depolymerisation) which the microbes can digest. As this process continues, the plastic molecule is broken down and digested away.
The biodegradability of plastic can be confirmed by comparing biodegradation results from an independent laboratory using either ASTM D5511, ASTM D5526 or Bio-Methane Potential (BMP) tests.
The diagram below illustrates the additive and the landfill-biodegradable process.