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Certified compostable: A more specific claim of biodegradability



Compostable plastics are those plastics which have been tested and certified by a third party to adhere to international standards such as ASTM D6400 (in the U.S.) or EN 13432 (in Europe) for biodegradation in an industrial composting facility environment.

Materials certified according to ASTM D6400 or EN 13432 will disintegrate within 12 weeks and biodegrade at least 90% within 180 days in a municipal or industrial composting facility. Approximately 10% of solid material will be left at the end of the six-month-long process in the form of valuable compost, or biomass and water. These standards also ensure that the leftover compost will be free of toxins, so the compost will not cause harm when the facility sells it for gardening or agricultural applications.

Unless otherwise denoted, certified compostable products must be disposed of in a designated municipal composting facility, not at home. Many certified compostable materials require the higher temperatures of industrial settings to biodegrade quickly enough, or in some cases at all.

Few areas in the U.S. have curbside collection for industrial composting, which is why certified compostable products are best utilized in closed systems such as amusement parks, stadiums and schools, where compostable and organic waste is carefully monitored and controlled to ensure proper disposal in an industrial composting facility. San Francisco International Airport and Safeco Field in Seattle are two good examples of organizations using composting as a means of reducing their carbon footprint and diverting organic waste from landfills.

Understanding bioplastics: Bio-based vs. biodegradable

To understand these three terms (i.e., biodegradability, compostability and oxo-degradability), it is important first to clearly understand the definition of bioplastics. Bioplastics refer to a large family of plastics which are sourced from biomass at the beginning of their life (bio-based), metabolized into organic biomass at the end of their life (biodegradable), or both.

Based on this, bioplastics can be broken down into three distinct classifications:

  1. Non-biodegradable and fully or partially bio-based (e.g., bio-based PET, bio-based PE.

  2. Biodegradable and petroleum-based (PCL).

  3. Both biodegradable and fully or partially bio-based (e.g., PLA or starch blends).

Biodegradable plastics are a relatively small subset of bioplastics which can be converted into water, carbon dioxide (CO2) and bio-mass over time with the help of micro-organisms — this process is called biodegradation. And because the biodegradability of a plastic lies with the chemical properties of the polymer —and not the source of the feedstock— biodegradable plastics can be either bio- or petroleum-based.

A quick note on oxo-degradable plastics


While often confused with biodegradable plastics, oxo-degradables are a category unto themselves. They are neither a bioplastic nor a biodegradable plastic, but rather a conventional plastic mixed with an additive in order to imitate biodegredation. Oxo-degradable plastics quickly fragment into smaller and smaller pieces, called microplastics, but don’t break down at the molecular or polymer level like biodegradable and compostable plastics. The resulting microplastics are left in the environment indefinitely until they eventually fully break down.

To add to the confusion, a similar term “Oxo-Biodegradable” is often slapped on some products.  People mistake the two terms for being one and the same thing. “Oxo-Biodegradable plastic uses metal salts to start degradation and to speed up the process, which result in extremely small fragments of plastic that no longer “visually” pollute the environment”. Further degradation depends on living organisms and bacteria. Products using this plastic typically don’t break down fully in normal landfills.  This may be due a lack of oxygen. Also, as another negative, some oxo-biodegradable plastics use Cobalt and carries the risk of further environment pollution.

When you are in the store, remember that there is a difference between biodegradable and oxo-biodegradable. Both affect the environment in different ways. Biodegradable products are actually environmentally safe and typically reduce the pollution. Where as oxo-biodegradable products may actually cause further pollution. There are a lot of products, which are biodegradable that can be bought at the store. These include trash bags, straws, and even shoes & watches!

Plastic recycling refers to the process of recovering waste or scrap plastic and reprocessing the materials into functional and useful products. This activity is known as the plastic recycling process. The goal of recycling plastic is to reduce high rates of plastic pollution while putting less pressure on virgin materials to produce brand new plastic products. This approach helps to conserve resources and diverts plastics from landfills or unintended destinations such as oceans.  


The Need for Recycling Plastic


Plastics are durable, lightweight and inexpensive materials. They can readily be molded into various products which find uses in a plethora of applications. Every year, more than 100 million tons of plastics are manufactured across the globe. Around 200 billion pounds of new plastic material is thermoformed, foamed, laminated and extruded into millions of packages and products. Consequently, the reuse, recovery and the recycling of plastics are extremely important.  


What Plastics Are Recyclable?


There are six common types of plastics. Following are some typical products you will find for each of plastic:

  1. PS (Polystyrene) – Example: foam hot drink cups, plastic cutlery, containers, and yogurt.

  2. PP (Polypropylene) – Example: lunch boxes, take-out food containers, ice cream containers.

  3. LDPE (Low-density polyethylene) – Example: garbage bins and bags.

  4. PVC (Plasticised Polyvinyl chloride or polyvinyl chloride)—Example: cordial, juice or squeeze bottles.

  5. HDPE (High-density polyethylene) – Example: shampoo containers or milk bottles.

  6. PET (Polyethylene terephthalate) – Example: fruit juice and soft drink bottles.

Currently, only PET, HDPE, and PVC plastic products are recycled under curbside recycling programs. PS, PP, and LDPE typically are not recycled because these plastic materials get stuck in the sorting equipment in recycling facilities causing it to break or stop. Lids and bottle tops cannot be recycled as well. “To recycle or Not to Recycle” is a big question when it comes to plastic recycling. Some plastic types are not recycled because they are not economically feasible to do so.


Some Quick Plastic Recycling Facts


  • Recycling plastic takes 88% less energy than producing plastics from new raw materials.

  • Currently, around 50% of plastics we use are thrown away just after a single use.

  • Plastics account for 10% of total global waste generation.

  • Plastics can take hundreds of years to degrade

  • The plastics that end up in the oceans break down into small pieces and every year around 100,000 marine mammals and one million seabirds get killed eating those small pieces of plastics.

  • The energy saved from recycling just a single plastic bottle can power a 100 watt light bulb for nearly an hour.


The Plastic Recycling Process


The simplest of plastic recycling processes involves collecting, sorting, shredding, washing, melting, and pelletizing. The actual particular processes vary based on plastic resin or type of plastic product. Most plastic recycling facilities use the following two-step process:

Step One: Sorting plastics automatically or with a manual sort to make sure all the contaminants are removed from the plastic waste stream. 

Step Two: Melting down plastics directly into a new shape or shredding into flakes then melting down before being finally processed into granulates.

The Latest Advances in Plastic Recycling

Ongoing innovations in recycling technologies have made the plastic recycling process easier and more cost-effective. Such technologies include reliable detectors and sophisticated decision and recognition software that collectively enhance the productivity and accuracy of automatic sorting of plastics. For an example, FT-NIR detectors can run for up to 8,000 hours between faults in the detectors.

Another notable innovation in plastic recycling has been in finding higher value applications for recycled polymers in closed-loop recycling processes. Since 2005, for example, PET sheets for thermoforming in the UK can contain 50 percent to 70 percent recycled PET through the use of A/B/A layer sheets.

Recently, some EU countries including Germany, Spain, Italy, Norway, and Austria have begun collecting rigid packaging such as pots, tubs, and trays as well as a limited amount of post-consumer flexible packaging. Due to recent improvements in washing and sorting technologies, the recycling of non-bottle plastic packaging has become feasible.


Challenges for the Plastic Recycling Industry


Plastic recycling faces many challenges, ranging from mixed plastics to hard-to-remove residues. The cost-effective and efficient recycling of the mixed plastic stream is perhaps the biggest challenge facing the recycling industry. Experts believe that designing plastic packaging and other plastic products with recycling in mind can play a significant role in facing this challenge.

The recovery and recycling of post-consumer flexible packaging is a recycling problem. Most material recovery facilities and local authorities do not actively collect it due to a lack of equipment that can efficiently and easily separate them. 

Oceanic plastic pollution has become a recent flashpoint for public concern. Ocean plastic is expected to triple in the next decade, and public concern has prompted leading organizations around the world to take action towards better plastic resource management and pollution prevention.

What do these terms mean? How are they different and which is the best one to choose?


Bio-based plastics are made in whole or partially from renewable biological resources. For example, sugar cane is processed to produce ethylene, which can then be used to manufacture for example polyethylene. Starch can be processed to produce lactic acid and subsequently polylactic acid (PLA).



The properties of bio-based plastics can vary considerably from material to material. Bio-based or partly bio-based durable plastics, so called "drop-in bioplastics”, such as bio-based or partly bio-based PE, PET or PVC, possess identical properties to their conventional versions. These bio-based plastics cannot be distinguished from conventional plastics other than by scientific analyses.


Bio-based plastics, such as starch blends, PLA, bio-PET and bio-PE, are mostly used in packaging applications. They are also used in fibres in the textiles sector. Bio-based succinic acid is suitable for several applications in sports and footwear, automotive, packaging, agriculture, non-wovens and fibres applications. In 2016, around 4.2 million tonnes of bio-based applications are produced annually; this is expected to increase to 6.1 million tonnes by 2021.


A straightforward explanation of biodegradable vs. compostable vs. oxo-degradable plastics

As consumer demand for sustainable products grows, bioplastics —which can reduce our reliance on fossil fuels and decrease greenhouse emissions— will become more prevalent. Production of bioplastics is expected to grow by as much as 20% by 2022, and as it does, consumer understanding of bioplastics will need to grow with it.

A major source of confusion is the difference between three terms: Biodegradability, compostability and oxo-degradability. Although these terms are often used interchangeably, they are not synonymous. Confusion regarding common bioplastics terminology such as these, especially where it concerns the disposal of bioplastic products, can have dire consequences. Companies need to understand the distinctions between each category in order to accurately and honestly market their products. And consumers need to understand these terms in order to make educated purchasing decisions and properly dispose of bioplastic products at the end of use.


Biodegradable vs. compostable vs. oxo-degradable plastics


Nearly every material will biodegrade, given enough time. But the length of the biodegradation process is highly dependent on environmental parameters such as humidity and temperature, which is why claiming that a plastic is “biodegradable” without any further context (i.e., in what timeframe and under what environmental conditions) is misleading to consumers.

Reputable companies will often make more specific claims, primarily certifying that their bioplastics are compostable. Compostable plastics are a subset of biodegradable plastics, defined by the standard conditions and timeframe under which they will biodegrade. All compostable plastics are biodegradable, but not all biodegradable plastics would be considered compostable.

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