The Meaning of the Terms
The terms biodegradable materials, biodegradation and compostability are often used the wrong way, so here we will differentiate these three.
What Does Biodegradable Mean?
Biodegradable refers to the ability of materials to break down and return to nature. For packaging products or materials to qualify as biodegradable, they must completely break down and decompose into natural elements within a short time after disposal – typically a year or less. The ability to biodegrade within landfills helps to reduce the build-up of waste, contributing to a safer, cleaner and healthier environment. Materials that are biodegradable include corrugated cardboard and even some plastics. Most plastics, however, are not biodegradable – meaning they cannot break down easily after disposal and can remain on the planet as waste for decades.
What Does Compostable Mean?
Compostable materials are like biodegradable materials, as they are both intended to return to the earth safely. However, compostable materials go one step further by providing the earth with nutrients once the material has completely broken down. These materials are added to compost piles, which are designated sites with specific conditions dependent on wind, sunlight, drainage and other factors. While biodegradable materials are designed to break down within landfills, compostable materials require special composting conditions. Compostable packaging materials include starch-based packing peanuts – an alternative to Styrofoam loose fill packaging that can be dissolved in water and added to composts for safe disposal.
Wrong use of the terms biodegradable and compostable can lead consumers to make wrong and costly choices. Several countries have now banned the use of the word “biodegradable” on packaging, because there is not much benefit if the end product still ends up in the landfill. Consumer products may be labelled as “compostable” as long as they conform to accepted standards.
The compost industry raised the concern where materials were labelled as biodegradable and compostable, and led to the making of the European Standard EN 13432 which describes qualifications for what can or cannot be labelled as compostable and/or biodegradable. European Standard EN13432 is ISO Standard basis. The said standards are meant to ensure that the materials will disintegrate in industrial composting conditions.
Materials that qualify the said European Standard will disintegrate effectively in all composting systems.
How a Product Meets the Standards
Each of these criteria is needed to qualify for the definition of compostability, but each point alone is not enough. For example; biodegradable is not necessarily compostable.
To be labelled as “compostable”, the material must have the following:
It is measured by metabolic conversion of the material to Carbon Dioxide to more than 90% in less than 6 months. (10% is allotted for sampling error
There should be dissolution below a certain size with no signs of contamination. This is tested by composting the materials for 3 months, after which is screened through a 2mm sieve. The mass of residues above 2mm must be not greater than 10% of the original mass.
Absence of negative effects on the final compost: This is tested by a plant growth test and physical/chemical analyses. There must be no difference from the control compost.
Other chemical/physical parameters that must not be different from those of the control compost after the degradation are: the pH, salinity, volatile solids, Nitrogen, Phosphorous, Magnesium and Potassium.
Low levels of heavy metals: Less than a list of specified values of certain elements
Each of these tests is undertaken according to internationally agreed methods of testing. Independent laboratory test results are then compared with the strict pass/fail limits set in the standard. Only if a material passes every ‘compostable’ test requirement is it proven to be ‘compostable’.
The Use of Logos
Each of these criteria is needed to qualify for the definition of compostability, but each point alone is not enough. For a couple of standards such as EN 13432, external certification bodies offer certification services and product assessment. In the case of compostable packaging, when an application is received, the certification body would review the ingredients and the nature of the packaging sample, and ensure it is delivered to a laboratory for testing. When the sample is received, the certification body will then check whether the lab test results report on the sample proves that it has passed the EN 13432’s criteria. If it has passed, a unique packaging product certification number and certificate is given, and it may bear the scheme’s certification mark/logo “compostable”.
Under this scheme, a product that carries the ‘compostable’ seedling logo must also display its 7P number. This allows end-users to trace the product to its source.
Ok Compost Logo
Certifies that the product is compostable in an industrial composting unit, including the components, inks and additives used. The certification programme’s sole reference point is the harmonised standard EN 13432: 2000, which means any product featuring the OK Compost mark is in fact in accordance with the EN13432 standard. With this marking system, users are guaranteed that the certified product can be composted in an industrial composting facility.
OK Biobased Logo
Certifies the product is contributing to resolving the economic and environmental problem of fossil fuels and greenhouse gases by using renewable raw materials. And that environmentally conscious motivation on the part of customers is exactly the reason why there is a need for an independent, high-quality guarantee of the renewability of raw materials which the OK Biobased logo states.