ENSO bottles claims that their bottles are "biodegradable in both landfill and compost environments and can also be successfully mixed with standard PET plastic recycling." How is that possible?
The Risks of Degradable Plastic
1) Increased consumption: Consumers will use more disposable plastics. This means more resources -- whether petroleum or corn or other raw material for the plastic as well as energy and water and more -- go into making single-use throw-away goods.
2) Greenhouse gas balance: much of the carbon in the biodegradable plastics will be emitted as CO2, or worse, as methane (which has a much stronger greenhouse effect than CO2). Is freeing up landfill space really worth releasing all that formerly petroleum-bound carbon into our warming atmosphere?
3) Toxicity of breakdown products: because polymers start out as long chains, it is very important to ensure that none of the smaller pieces that occur as part of being broken down by microbes are toxic in their own right. ENSO has done testing and reports that all steps on the breakdown chain have no negative impacts on the environment. But in the race to get new plastics to the market, testing and caution must be the rule.
So is Biodegradable Plastic Good or Bad?
Biodegradable plastics are just one more tool in the waste management box. Particularly for hard-to-recycle plastic wastes, such as when plastic is bonded to other materials to provide a grease or liquid barrier, these new plastics are a bonus. The entire container can be designed to biodegrade and become a managable waste rather than a straight-to-landfill item. But accepting biodegradable plastic as a silver bullet is premature.