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Biodegradable vs. Compostable

Writer: Life Cyle Indonesia
Life Cyle Indonesia
6 hours ago
4 min read

Imagine you are sorting four everyday items into waste buckets: an apple core, a certified PLA bio-plastic coffee cup, a plastic bag labeled simply as "biodegradable" without certification, and a standard PET plastic water bottle. Consider whether each item is both biodegradable and compostable, biodegradable only, or neither.


Most of us may want to make greener choices, but navigating product packaging often feels like reading a secret code. Terms like "biodegradable" and "compostable" are frequently used to sell us on "green" packaging. Treating them as identical can be misleading and in reality, they represent distinct scientific processes. 


One golden rule: all compostable items are biodegradable, but not all biodegradable items are compostable. 


Biodegradable: Unspecified Timeframe


Biodegradable, which is mainly used in plastic,  means a material can be broken down by naturally occurring living organisms, such as bacteria, fungi, and algae, into natural elements like water, carbon dioxide, and biomass.


Science dictates that almost everything will eventually biodegrade given enough time—even conventional plastics will break down over hundreds of years. However, as they degrade, traditional plastics fragment into harmful microplastics and leave behind toxic chemical residues. Without an explicit standard or certified testing environment, labeling a product "biodegradable" offers no guarantee of how quickly it breaks down or what it leaves behind in the ecosystem.


Compostable: Decomposition on a Fixed Clock


According to the Ellen MacArthur Foundation, compostable materials are able to be broken down into carbon dioxide, water, and biomass within a specific time-frame under specific conditions.


Unlike biodegradation, compostability involves two distinct pathways:


  • Home-Compostable: Breaks down at ambient temperatures with a natural microbial community (like a backyard compost bin).

  • Industrially Compostable: Breaks down under increased temperatures, controlled humidity, and specifically formulated microbial conditions found only in specialized commercial facilities.


Note: Compostable materials can be made from either bio-based (plant) or petro-chemical inputs, and compostable packaging is subject to strict certification standards across North America, Europe, and Japan.


Key Differences at a Glance


Beyond basic definitions, their real-world impact depends on how they behave after disposal. Here is a quick breakdown of how they compare:

Property

Biodegradable

Compostable

Timeframe

Unspecified (weeks to centuries)

Strict: Must meet defined biodegradation and disintegration requirements under the applicable composting standard

Required Conditions

Depends on the specific biodegradation claim; may require particular temperature, moisture, oxygen, microorganisms, etc.

Controlled (specific heat, moisture, oxygen levels)

End Product

Water, CO2, biomass, potential microplastics

Compost, biomass, CO₂, water, and inorganic compounds without harmful residues

Landfill Behavior

Slowly degrades; can release methane (under anaerobic conditions)

Will not decompose properly due to lack of oxygen


Even with the differences, marketing terms can still be confusing in everyday practice. Here are three common traps to watch out for:


  • Biobased ≠ Compostable


"Biobased" refers to where the material comes from (plant sources like corn or sugarcane) rather than how it behaves after use. However, biobased plastics like bio-PET are chemically identical to conventional plastic and will not compost. Only specifically engineered biopolymers (like PLA) qualify.


  • Home vs. Industrial Composting

Commercial compostable items require sustained high heat (50°C–70°C / 122°F–158°F), moisture, and aeration found only in industrial facilities. They generally will not break down in a standard backyard compost pile.


  • Never Mix with Standard Recycling

Compostable plastics must never be placed in standard plastic recycling bins. Because they melt at lower temperatures than traditional resins, adding compostable items can ruin an entire batch of recycled plastic.


Practical Guide: Look for Recognised Certifications


Because vague claims like 'eco-friendly' or 'biodegradable' offer no real guarantees, checking for verified third-party certifications is the only way to know how to handle the product correctly:


Certification Bodies & Labels


  • BPI Certified & CMA (North America): Independently test and verify that products safely break down in commercial composting facilities without contaminating the soil.

  • TÜV AUSTRIA OK compost HOME: Certifies that a product can decompose in the lower heat of a home composting environment in less than a year. 


Technical Standards Behind the Logos

  • ASTM Standard D6400: For a product to be labeled “industrially compostable” or “commercially compostable,” it must meet standards established by the American Society for Testing and Materials (ASTM). Standard D6400 indicates that breakdown occurs within 180 days and that the final product is not toxic to the environment. This is also equivalent to EN13432, which assures the same in Europe and abroad.

  • ASTM Standard D6868: ASTM D6868 indicates products that can be composted in industrial aerobic composting facilities without negatively affecting the environment. This standard is used for products with a film or coating made with biodegradable plastic.


Making sustainable choices starts with reading the label correctly. However, a compostable item is only as green as the facilities available to process it. Checking whether your local area has industrial composting, home compost options, or standard recycling ensures your purchasing choices lead to real environmental gains.


The information presented in this article is accurate as of the publication date, based on publicly available data. LCI may periodically update this article to reflect evolving standards and regulations. 


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