How Is Biodegradable Plastic Different from Compostable Plastic?

With environmental awareness growing across the globe, terms like biodegradable and compostable have become popular in discussions about plastic alternatives. However, while both are linked to sustainability, they are not the same. Consumers, businesses, and even some policymakers often use these words interchangeably, which leads to confusion and even unintentional misuse.

To make environmentally sound decisions—whether you’re shopping for everyday items or sourcing packaging for your business—it’s important to understand the actual differences between biodegradable plastic and compostable plastic.

The Basics of Decomposition

Both biodegradable and compostable plastics are designed to break down after disposal, unlike conventional plastics that persist in the environment for hundreds of years. The key difference lies in how, where, and under what conditions they decompose.

Biodegradable plastic refers to materials that naturally break down into water, carbon dioxide, and biomass with the help of microorganisms. This can occur in various environments such as landfills, oceans, or soil, depending on the type of material. However, the process may take months or even years and is not always predictable or complete.

Compostable plastic, on the other hand, is engineered to break down in a controlled composting environment, usually within a specific timeframe. This process also results in water, carbon dioxide, and organic matter but must meet specific industrial or home composting standards. It’s a faster and cleaner form of decomposition, provided the right conditions exist.

Standards and Certifications

One of the key factors that set compostable materials apart is certification. Compostable plastics must meet stringent guidelines set by organizations such as ASTM (in the U.S.) or EN13432 (in Europe). These certifications ensure that the material fully disintegrates within a set period and does not leave toxic residues behind.

Biodegradable plastics, however, are not always subject to standardized certifications. A product labeled as biodegradable might only partially decompose or require specific conditions that are rarely met in natural environments. This lack of regulation can lead to greenwashing, where companies market their products as environmentally friendly without real proof.

Environmental Impact and End-of-Life Considerations

The ultimate goal of switching to sustainable materials is to reduce environmental harm. Compostable plastic performs better in this regard because it breaks down into non-toxic components and enriches the soil when composted properly. It fits well into circular waste systems and aligns with zero-waste lifestyles.

Biodegradable plastic, while a better alternative to traditional plastic, can still cause environmental issues if not managed properly. In landfills, it may break down anaerobically (without oxygen), producing methane—a potent greenhouse gas. Some biodegradable variants also contain petrochemical ingredients that leave behind microplastics during degradation, contributing to pollution rather than solving it.

Application in Everyday Products

Both types of plastic are widely used across industries—from packaging and agriculture to fashion and food service. Biodegradable plastic is often found in shopping bags, agricultural mulch films, and disposable utensils. It’s also used in cases where products are not likely to end up in composting facilities.

Compostable plastic is especially common in food packaging, catering disposables, and waste bags. Its controlled decomposition makes it suitable for applications where organic waste is collected and composted, such as in cafes, homes, and corporate offices practicing sustainable waste management.

Challenges and Considerations

While these alternatives offer hope, they also bring new challenges. One of the biggest issues is infrastructure. Compostable materials require access to composting facilities, and many regions still lack the systems needed to process them. Without the right setup, even compostable items can end up in landfills, undermining their benefits.

Another challenge is public education. Many people dispose of compostable or biodegradable items incorrectly, sending them to recycling or landfill where they don’t break down as intended. This mismanagement slows progress toward cleaner waste systems.

Clear labeling, consumer awareness, and proper collection systems are all crucial to ensure that these sustainable materials deliver on their promise.

Conclusion: Choosing the Right Alternative

Understanding how biodegradable plastic differs from compostable plastic is key to making responsible choices. While both offer improvements over conventional plastic, they serve different purposes and require different handling.

If your goal is to contribute to a zero-waste future and you have access to composting, compostable plastic is the better option. If composting infrastructure is not available, biodegradable materials can still offer a more eco-conscious solution—provided they are carefully chosen and correctly disposed of.

In the end, the shift away from traditional plastic is not just about replacing one material with another. It’s about adopting a mindset that values sustainability, minimizes harm, and supports a cleaner, more responsible way of living.