As a supplier of compostable poly bags, I often encounter questions from customers regarding the compatibility of our products with various waste materials. One of the most frequently asked questions is whether compostable poly bags are suitable for composting cardboard. In this blog post, I will delve into this topic, exploring the science behind composting, the properties of compostable poly bags and cardboard, and the practical considerations for using these materials together.
Understanding Composting
Composting is a natural process that involves the decomposition of organic materials by microorganisms such as bacteria, fungi, and worms. These microorganisms break down the organic matter into a nutrient-rich soil amendment known as compost. The process requires a balance of carbon-rich materials (browns), nitrogen-rich materials (greens), oxygen, and water. Cardboard is a classic example of a carbon-rich material, while food scraps and grass clippings are nitrogen-rich.
Properties of Compostable Poly Bags
Compostable poly bags are designed to break down under specific composting conditions. They are typically made from biodegradable polymers derived from renewable resources such as corn starch, potato starch, or polylactic acid (PLA). These materials are engineered to degrade into carbon dioxide, water, and biomass within a defined period, usually within 180 days under industrial composting conditions.
The key advantage of compostable poly bags is that they offer a sustainable alternative to traditional plastic bags, which can take hundreds of years to decompose and often end up in landfills or the environment. Compostable poly bags can help reduce the environmental impact of plastic waste and contribute to a circular economy by returning organic matter to the soil.
Properties of Cardboard
Cardboard is a widely used packaging material made from paper pulp. It is a renewable and recyclable resource, and when disposed of properly, it can be recycled into new cardboard products. However, cardboard can also be composted, as it is a carbon-rich material that provides a source of energy for the microorganisms involved in the composting process.
Cardboard breaks down relatively slowly compared to other organic materials, as it has a high lignin content, which is a complex polymer that resists decomposition. To speed up the composting process, it is recommended to shred or tear the cardboard into small pieces to increase the surface area available for microbial activity.
Compatibility of Compostable Poly Bags and Cardboard
The compatibility of compostable poly bags and cardboard depends on several factors, including the type of composting system, the composition of the compostable poly bags, and the condition of the cardboard.
Industrial Composting
In industrial composting facilities, which are equipped with large-scale composting equipment and controlled environmental conditions, compostable poly bags and cardboard can be composted together. These facilities typically operate at high temperatures (between 55°C and 65°C) and have a well-defined composting process that ensures the efficient decomposition of organic materials.
Compostable poly bags are designed to meet the standards for industrial compostability, such as the ASTM D6400 or EN 13432 standards. These standards specify the requirements for the biodegradability, disintegration, and ecotoxicity of compostable materials. When used in industrial composting facilities, compostable poly bags will break down within the specified time frame, along with the cardboard, to produce high-quality compost.
Home Composting
Home composting systems, on the other hand, are typically smaller in scale and have less control over the composting conditions. The temperature, moisture, and oxygen levels in home composting systems can vary widely, which can affect the decomposition rate of compostable poly bags and cardboard.
While some compostable poly bags are labeled as suitable for home composting, it is important to note that home composting conditions may not always meet the requirements for complete decomposition. In general, home composting systems operate at lower temperatures (around 20°C to 40°C) and may not have the same level of aeration and moisture control as industrial composting facilities.
As a result, compostable poly bags may take longer to break down in home composting systems, and there is a risk that they may not fully decompose within a reasonable time frame. Additionally, some home composting systems may not be able to handle the high volume of cardboard that is generated in a household, which can lead to slow decomposition and the formation of a compacted layer in the compost pile.
Practical Considerations
When using compostable poly bags for composting cardboard, there are several practical considerations to keep in mind:
- Check the Label: Before using compostable poly bags, make sure to check the label to ensure that they are suitable for the type of composting system you are using. Some compostable poly bags are only suitable for industrial composting, while others may be suitable for both industrial and home composting.
- Prepare the Cardboard: To speed up the composting process, shred or tear the cardboard into small pieces before placing it in the compostable poly bag. This will increase the surface area available for microbial activity and help the cardboard break down more quickly.
- Mix with Other Materials: To create a balanced compost pile, mix the cardboard and compostable poly bags with other organic materials such as food scraps, grass clippings, and leaves. This will provide a source of nitrogen and help maintain the proper carbon-to-nitrogen ratio in the compost pile.
- Monitor the Compost Pile: Regularly monitor the compost pile to ensure that it is maintaining the proper temperature, moisture, and oxygen levels. Turn the compost pile every few weeks to aerate it and promote decomposition.
- Be Patient: Composting is a natural process that takes time. It may take several months for the cardboard and compostable poly bags to fully decompose, depending on the conditions of the composting system. Be patient and allow the microorganisms to do their work.
Conclusion
In conclusion, compostable poly bags can be suitable for composting cardboard, but the compatibility depends on the type of composting system and the specific properties of the compostable poly bags and cardboard. In industrial composting facilities, compostable poly bags and cardboard can be composted together to produce high-quality compost. However, in home composting systems, the decomposition process may be slower, and there is a risk that the compostable poly bags may not fully decompose within a reasonable time frame.
As a supplier of compostable poly bags, I recommend that customers carefully consider their composting needs and choose the appropriate type of compostable poly bags for their specific situation. If you are unsure whether compostable poly bags are suitable for your composting system, I encourage you to consult with a composting expert or contact your local waste management authority for guidance.
If you are interested in purchasing compostable poly bags for your composting needs, I invite you to explore our range of Bioplastic Bags. Our products are made from high-quality, biodegradable materials and are designed to meet the highest standards of compostability. We also offer HDPE Medical Waste Biohazard Bag and Biohazard Waste Bags for specific waste management applications.
Contact us today to discuss your requirements and learn more about how our compostable poly bags can help you achieve your sustainability goals.
References
- ASTM International. (2019). Standard Specification for Compostable Plastics. ASTM D6400-19.
- European Committee for Standardization. (2000). Packaging - Requirements for Packaging Recoverable through Composting and Biodegradation - Test Scheme and Evaluation Criteria for the Final Acceptance of Packaging. EN 13432:2000.
- Composting Council of Canada. (n.d.). Composting Basics. Retrieved from https://compostingcouncil.ca/composting-basics/