AS 4736 Biodegradable Plastics - Biodegradable Plastics Suitable for Composting and Other Microbial Processes

An Australian standard, AS 4736 Biodegradable plastics - Biodegradable plastics suitable for composting and other microbial processes, specifies requirements and test methods for determining the compostability or anaerobic biodegradation of plastics, addressing biodegradability, breakdown during biotreatment, effect on biotreatment process and effect on quality of resulting compost. This standard provides a basis for allowing materials or products made from plastics to be labelled as compostable for use in facilities such as municipal or industrial composting establishments. This standard applies to the processing of plastics in controlled waste treatment facilities.

Products and materials that meet this standard are compostable and biodegradable plastics. The label on these products clearly states that the packaging materials are biodegradable and compostable. In order for a product to be certified as compostable and carry this label, suitable biopolymer materials must undergo a rigorous testing regime in accordance with the AS 4736 standard and these tests must be conducted by recognised independent accredited laboratories.

In the plastic packaging industry, the term biodegradable is often used to refer to plastic bags that break down in landfills or in the natural environment. However, the term is meaningless without industry standards or criteria to determine whether a piece of plastic is biodegradable. In fact, there is nothing that does not break down in nature. Even steel oxidizes and corrodes over time, but just like plastics, this process takes many years.

In the plastic packaging industry, biodegradable refers to plastic packaging that has additives added to it to break down more quickly in landfills or in nature. This process still takes many years, but more problematically, it leaves toxic residue or microplastics in the environment.

The term biodegradable is often used instead of compostable, but these concepts are different. Composting is a form of waste disposal in which organic waste, such as food, naturally decomposes under conditions rich in oxygen and microbes. There are industrial composting facilities and composting systems for homes. Compostable packaging should be disposed of in these facilities or systems. Because compostable packaging is made from raw materials (such as corn starch) that naturally decompose in environments rich in microbes and oxygen, just like organic waste. The benefit of this is that the packaging not only does not end up in landfill, but when composted, it can help fertilize plants and vegetation. In the end, this method is a real step towards sustainable packaging.

For a plastic material to be certified as compostable, it must comply with the AS 4736 standard. This standard is similar to the European EN 13432 standard, but includes an additional requirement for worm testing. The AS 4736 standard provides criteria for assessing plastic materials that will biodegrade in industrial anaerobic composting facilities. Industrial composting facilities are very different from home composting systems. Industrial composting facilities can process organic waste at high temperatures (50 degrees or higher) that cannot be replicated at home, thus increasing the rate at which the waste decomposes. Therefore, just because something is certified to AS 4736 does not mean that it will decompose in the same way in a home composting system!

To comply with the AS 4736 standard, plastic materials must meet the following requirements:

• Plastic materials must biodegrade to a minimum of 180 percent within 90 days in compost.
• At least 90 percent of plastic materials should be broken down into pieces smaller than 12 mm in the compost within 2 weeks.
• The resulting compost has no toxic effects on plants and worms.
• Hazardous substances such as heavy metals must not exceed the maximum allowable levels.
• Plastic materials must contain more than 50 percent organic matter.

Products that meet these requirements are certified in accordance with the AS 4736 standard. This document ensures that these products and materials can be easily identified and that food waste or organic waste contained in these certified products can be easily separated and removed from landfills.

The aim of compostable packaging is to have less waste end up in landfill, especially single-use bags. However, if, for example, compostable garbage bags are used to pack inorganic waste and are thrown in landfill, the purpose of the compostable nature of the bag is defeated. Therefore, to ensure that such packaging is disposed of properly, instructions for proper disposal should be included with the contents of compostable packaging. It is important to know how to dispose of the packaging.

Our organization has a strong staff that closely follows the developments in the world in the field of science and technology and constantly improves itself. Among the numerous test, measurement, analysis and evaluation studies provided for businesses in various sectors, there are also testing services in accordance with the standard "AS 4736 Biodegradable plastics - Biodegradable plastics suitable for composting and other microbial processes".