It is worth defining, then, what exactly constitutes a biodegradable and compostable plastic material. Here we turn to the Australasian Bioplastics Association (ABA), which has helpfully provided an outline of the requirements of Australian standard AS 4736-2006.
This standard "provides assessment criteria for plastic materials that are to be biodegraded in municipal and industrial aerobic composting facilities."
While it is similar to the well known European EN 13432 standard, the Australian standard has an additional requirement of a worm test.
The ABA notes that in order to comply with AS 4736-2006, plastic materials must meet the following requirements:
- minimum of 90% biodegradation of plastic materials within 180 days in compost
- minimum of 90% of plastic materials should disintegrate into less than 2mm pieces in compost within 12 weeks
- no toxic effect of the resulting compost on plants and earthworms.
- hazardous substances such as heavy metals should not be present above the maximum allowed levels; and
- plastic materials should contain more than 50% organic materials.
The ABA leverages a third‐party verification system to assist manufacturers, distributors and retailers to communicate their compliance to this standard hence verify product quality with respect to biodegradability claims.
Two companies of note on Ferret.com.au that have undertaken this third-party verification process are Innovia Films and BioPak . Both have been awarded a Certificate of Conformance to the AS 4736-2006 standard.
Innovia Films was awarded the Certificate for its NatureFlex family of speciality packaging films, which are manufactured from a compostable cellulose-based material. In addition to being certified to the Australian standard, NatureFlex films are also certified to the European (EN13432) and American (ASTM D6400) standard.
BioPak supplies a wide range of starch based compostable bags that are made from Australian certified compostable bioplastics. The company states that these bags will safely turn into healthy compost in just 12 weeks, ultimately turning into carbon dioxide, water, and non-toxic raw materials.