Polylactic Acid (PLA) is a widely adopted bioplastic derived from renewable sources such as fermented plant starches, including corn, sugarcane, or cassava. Synthesized from lactic acid, PLA has a lower carbon footprint compared to traditional petroleum-based plastics. Although PLA is often discussed as biodegradable, its decomposition requires a specific, controlled environment to break down effectively.
Understanding Composting Requirements for PLA
The label “compostable” for PLA refers to its ability to break down under the intense conditions of a commercial or industrial composting facility. This industrial setting is necessary because the PLA polymer chains must first undergo hydrolysis, the breaking of chemical bonds by water. This initial step is significantly accelerated by sustained, high temperatures rarely achieved in a backyard compost pile.
Industrial facilities maintain thermophilic conditions, typically between 131°F and 140°F (55°C to 60°C). This heat is generated by the metabolic activity of specialized microbial communities. Commercial composters also maintain precise moisture levels, usually around 60% water content, and ensure adequate oxygen for the microorganisms to thrive.
Home composting systems operate at much lower and more variable temperatures, often staying below the necessary threshold to initiate PLA’s breakdown. Without sustained heat, the PLA polymer remains intact and will not decompose within the typical composting cycle. Attempting backyard composting is ineffective and risks contaminating the finished compost. The required industrial conditions allow certified PLA to disintegrate by at least 90% within 12 weeks and mineralize into carbon dioxide, water, and biomass within six months.
Physical Preparation Before Composting
Proper preparation is necessary before sending any PLA item to a commercial facility to ensure it is accepted and processed efficiently. The first step involves thoroughly cleaning the item to remove all food residue or organic contaminants. Remaining food particles can disrupt the composting process and may lead to the material’s rejection at the processing facility.
Next, you must verify that the item is indeed a certified compostable bioplastic, as contamination with conventional plastic is a major issue for facilities. Look for certification symbols such as the ASTM D6400 standard in North America or the European EN 13432 standard, often displayed as the “OK compost INDUSTRIAL” mark. The presence of these marks confirms the material is scientifically validated to break down in an industrial setting.
Reducing the size of the PLA item is highly recommended to accelerate the process. Cutting or shredding the material into smaller pieces increases the total surface area exposed to heat and microbes. This physical preparation speeds up the initial hydrolysis phase, allowing the material to break down more quickly once it reaches the commercial composter.
Utilizing Commercial Composting Services
Since home composting is not viable for PLA products, utilizing commercial services is the only way to ensure successful decomposition. Check if your local municipal waste program offers specialized collection for certified compostable materials, often through a green bin program. Confirm that the municipal facility is equipped to handle bioplastics, as not all are capable of maintaining the required high temperatures.
If municipal services are unavailable, explore private composting companies or subscription drop-off services in your area. These dedicated commercial haulers often specialize in organic waste and are more likely to partner with facilities that process PLA. Resources like the United States Composting Council maintain directories that can help locate certified composters and haulers that accept commercial bioplastics.
Before committing to any service, contact the specific facility directly to confirm their acceptance policy for PLA products. Industrial composting capabilities vary widely, meaning facilities may have different requirements regarding certification marks or the physical form of the PLA they accept. This verification step ensures your prepared PLA material is successfully diverted from the landfill and properly composted.