When it comes to biodegradable plastics, the three main choices are Oxo-Degradable (sometimes just called ‘degradable’), Compostable, and now Landfill-Biodegradable (which is our choice).
The table below summarises these technologies.
|100% biodegradable in landfills?||Yes||No||No|
|100% recyclable with other mainstream plastics?||Yes||No||No|
|Special storage conditions required?||No||Yes||No|
|Shelf life / has expiration dates?||No||Yes||No|
|Will degrade when exposed to sunlight or high heat||No||Yes||No|
|Fragments into small pieces in air||No||Yes||No|
|Biodegradation begins at time of disposal; not before||Yes||No||Yes, in compost facility only|
|Will biodegrade in commercial and municipal composts||Yes||No||Yes|
|Needs oxygen in order to biodegrade||No||Yes||Yes|
Bio-Gone Plastics uses a patented additive to make our disposable products landfill-biodegradable. This means that the plastics will decompose under typical landfill environmental conditions much faster than traditional plastics which have an indefinite life span. Biodegradation of plastic is achieved by enabling microorganisms to metabolize (i.e. break down) the molecular structure of the plastic, which produces an humus-like material (organic matter that cannot break down any further) which is a natural plant fertilizer. There are two different ways this is achieved in industry.
Landfill-Biodegradable Plastics are made by combining traditional plastic, which is petroleum-based, with an organic additive. The biodegradation only begins when the plastic is exposed to a microbe rich environment such as in a landfill. The additive attracts microbes to the plastic and they start to digest it. As they do this, the enzymes the microbes secrete cause the plastic polymer molecules to break down into shorter chains, which the microbes can then begin to digest them too. The biodegradability of a plastic can be confirmed using the standard laboratory test ASTM D5511.
Advantages of Landfill-Biodegradable plastics:
Another type of biodegradable plastic often mentioned is known as ‘Compostable’. These are a type of plastic made from renewable sources rather than petroleum-based plastics and will quickly biodegrade in a commercial compost facility (not in a backyard compost or garden bed). The more common types of bioplastics are:
Although the manufacturing of bioplastic materials is reliant upon petroleum as an energy and materials source, it is generally regarded as a more sustainable activity (due to carbon sequestration) when compared to petroleum-based plastics. Compostable plastics are bioplastics that biodegrade under commercial composting conditions as per ASTM 6400*. Note that not all bioplastics are compostable. Bio-Gone Plastics does not use compostable plastics.
* To meet ASTM 6400 standards, a plastic needs to exhibit 60% biodegradation within 180 days in commercial composting conditions.
Confusion exists over the term bioplastic. Some people think that a bioplastic is automatically biodegradable. This is not the case. A bioplastic is a plastic made from plant materials. There is no inference about its biodegradability. Polyethylene plastic can be made from sugar cane, but it is no more biodegradable than polyethylene made from petroleum.
The other question regarding bioplastics is, should we really be using good arable land for growing crops destined for bioplastics when the world has a food shortage?
Limitations to compostable plastics
At the present time there are several limitations for compostable plastics that make them not a suitable choice for controlling plastic waste.
Confusion also exists over the term ‘Degradable’ plastics. A degradable plastic is a plastic with a metallic additive that sets off a slow chemical reaction and over 12-24 months will cause the plastic to fragment into little pieces. This has nothing to do with biodegradation and microorganisms, and so instead of 1 piece of plastic we end up with hundreds or thousands of little pieces of plastic, which is a worse result for the environment.
Also, the reaction will only work in the presence of oxygen and sunlight. So if a degradable plastic is buried in a landfill where there is no sunlight and very little oxygen, it will stay there like a conventional plastic not degrading. Therefore for a degradable plastic to fragment down into little pieces it has to be up on top of the ground and there those little pieces will blow around and disperse into the environment. Bio-Gone Plastics does not use degradable additives.