Compostable defines a product or material that can be broken down by nature into naturally occurring products within a period of 180 days at 140 degrees F in the United States, the EN 13432 represents the time frame allowed in Europe of 180 days at 131 – 134.5F. Most materials that are viewed as compostable take a period of time to be broken down by heat in order for the microbes to have the ability to consume these products.
Composting
Most composting facilities operate their composting establishments at 120-160F, the reason for this is to kill pathogens that are dangerous to the environment. The EPA notes that composting conditions effect the nitrious oxide which is in the environment a green house gas 296 times more potent than CO2. When creating the compost with compostable materials it is important that the amount of nitrogen that is placed into the system is 20 carbon and 1 nitrogen. Microorganisms do not need a large amount of nitrogen to live and therefor the product consumption of nitrogen is low when consuming the carbon content within the compost.
PolyLactic Acid
PLA which is manufactured around the world by various manufacturers has the ability to be broken down by 140F within a period of time based on thickness. The EPA has done studies around PLA and the degredation rate of PLA when formed into articles to be used by consumers. These materials do not break down in home composting conditions, they are only broken down by heat and hydrolysis over a period of time in specific environments. The EPA notes that soup cups and utensils made for eating hot food items take 6-12 months for complete compostability of the products. Most of the PLA products take between 3-6 months to completely compost in the 140F temperatures found in industrial compost facilities.
PHA
PHA’s are materials manufactured by companies from natural occurring biodegradation of products. PHA’s are manufactured by bacteria which can be used for polymers to be molded, extruded into useful products. PHA’s are vast and the difference between each strain or polymer of PHA have different abilities in our environment. In some cases PHA’s can be home composted without industrial compost facilities like PLA. PHA material has a barrier to entry due to costs of the material.
Compost Testing
When testing if your product is compostable or not compostable you will need to test your product under the EN 13432 or the ASTM D6400 tests. The ASTM D5338-12 test method is used to see if your product is compostable based on the standard ASTM D6400.
