A product that is “compostable” is one that can be placed into a composition of decaying biodegradable materials, and eventually turns into a nutrient-rich material.  It is almost synonymous with “biodegradable”, except it is limited to solid materials and does not refer to liquids.

Composting occurs in nature every day as fallen leaves and tree limbs biodegrade into the forest floor.  The EPA considers composting a form of recycling because it turns resources into a usable product.

Compost piles have been used by many farmers and gardeners for generations.  Food, leaves, grass clippings, garden wastes, and tree trimmings (which amount to between 50 and 70 percent of waste in this country) can all go into the compost pile, where hungry microorganisms eat the waste to produce carbon dioxide, water and humus.  The resulting compost is an excellent natural fertilizer proven by organic gardeners to restore soil fertility, control weeds, retain ground moisture and reduce soil erosion.

While backyard compost piles are well known, the newest application of composting is municipal composting, which works on the same natural principles, but is done on a much larger scale.  Over 2,200 communities already compost their leaves, grass and yard trimmings.  Approximately 55 additional communities compost or are about to compost all their organic trash at well-sited, professionally managed composting facilities.

Municipal composting requires minimal time, effort and labor, since most of the work is done by the microorganisms.  Communities can also use or sell the resulting compost for agricultural and horticultural uses, or to restore depleted lands.  Unlike landfills, a composting site can be continually reused without ever reaching capacity.

As with the term biodegradable, regulators recommend that the term compostable not be used unless the product is currently composted in a significant amount in the area where it is sold.  Without the ability to actually compost the product, claim is considered to be meaningless and thus deceptive.  They recommend that any product promoted as “compostable” should clearly and prominently disclose that the product is not designed to degrade in landfills.

There are no federal regulations regarding the use of the term “compostable”, but the Federal Trade Commission does give guidelines.

They say, “An unqualified claim that a product or package is compostable should be substantiated by competent and reliable scientific evidence that all the materials in the product or package will break down into, or otherwise become part of, usable compost (e.g., soil conditioning material, mulch) in a safe and timely manner in an appropriate composting program or facility, or in a home compost pile or device.”

Claims may be considered deceptive if: (1) municipal composting facilities are not available to a substantial majority of consumers or communities where the package is sold; (2) the claim misleads consumers about the environmental benefit provided when the product is disposed of in a landfill, or (3) consumers misunderstand the claim to mean that the package can be safely composted in their home compost pile or device when, in fact, it cannot.

 

In this section we also wanted to address and define the term, “Oxo-degradable.” Many plastic products that DO NOT and CAN NOT meet the compostability standards have labeled themselves Oxo-Degradable. These plastics are mainly based on polyethylene and contain additives that cause the plastic to degrade. The additives are typically organic compounds of transition metals (such as cobalt, iron, nickel, and manganese).

More specifically, Oxidative degradation is a complex series of chemical reactions in which the long chains of polyethylene molecules are broken down into shorter lengths by the action of oxygen, ultra-violet light and/or heat. This degradation process causes deterioration in the strength of the plastic, which becomes brittle and easily fragments into small pieces. “Fragment” is the key here. The fate of plastic fragments that remain in the soil is an area of uncertainty. Although these are regarded as beneficial by the producers, concerns have been raised that these particles of plastic may be ingested by invertebrates, birds, animals or fish. Additionally, one should also should be quite suspicious of any manufacturer making claims that their products will degrade in an air-locked landfill, which is absent of oxygen and ultra-violet light. The majority of landfills in the U.S. are anaerobic (air-locked) landfills.

Again, Oxo-degradable plastics are not compostable, according to established international standards EN13432 and ASTM 6400. Oxo-degradable plastics should not be included in waste going for composting, because the plastic fragments remaining after the composting process might adversely affect the quality and saleability of the compost.

Also, Oxo-degradable plastics are not suitable for recycling with main-stream plastics as they have an adverse effect on the quality and usability of the finished recycled product.

PLA is a biodegradable and biobased thermoplastic polyester derived from renewable resources, such as sugarcane or cassava. PLA is one of the highest quality and one of the most popular biopolymers on the market. Since providing a high level of purity of the PLA is not so easy, only the fewest manufacturers achieve this.

 

Verifood includes the traditional PLA grades as well as the latest developments on high heat PLA. Due to the special material properties, our weforyou PLA can be used for a wide range of markets and industries. These include food packaging, consumer goods, medical equipment products, food packaging, fiber and non-wovens.

 

Due to the latest developments and high material purity, our PLA is also resistant to heat. It offers completely new industrial uses and can therefore replace other types of plastic. High-quality PLA can partially or totally replace LDPE, HDPE, PP, PA, PS and PET. PVC shrink films and PVC cards can also be replaced by PLA.

Compostable Plastics Quick Facts

  • Generally Freezer safe
  • Depending on resin can handle hot food till 200F.
  • Fully compostable in commercial composting operations
  • Feel and look like plastics for the most part
  • Est. Home Composting Time: Varies, See Table
  • Est. Commercial Composting Time: Varies, See Table
  • Reports and Test Results

 

Compostable Plastics are a new generation of plastics which are biodegradable through composting. They are derived generally from renewable raw materials like starch (e.g. corn, potato, tapioca etc), cellulose, soy protein, lactic acid etc., are not hazardous/toxic in production and decompose back into carbon dioxide, water, biomass etc. when composted.  Some compostable plastics may not be derived from renewable materials, but instead derived made from petroleum or made by bacteria through a process of microbial fermentation.

 

Currently, there are a number of different compostable plastics resins available in the market and the number is growing every day. The most commonly used raw material for making the compostable plastics is corn starch, which is converted into a polymer with similar properties as normal plastic products. Other compostable resins are available made from potato starch, soybean protein, cellulose and as well from petroleum and petroleum by products. It is counter intuitive to think that compostable resins could be derived from petroleum, when all normal plastic products are derived from petroleum and are non compostable. However, there are certified compostable resins available in the market, derived from petroleum and the field of compostable plastics is constantly evolving with new materials and technologies being worked on and being brought to market. There is even research underway to make compostable plastics from carbon dioxide.

 

Properties The compostable resins for the most part mimic plastic properties, and different resins have different properties related to heat resistance, tensile strength, impact resistance, MVTR, oxygen barrier etc. One of the main compostable resin PLA, for example has a heat resistance of only 110F, while other compostable resins can have a much higher heat resistance.

Bioplastics can take different length of times to totally compost, based on the material and are meant to be composted in a commercial composting facility, where higher composting temperatures can be reached and is between 90-180 days. Most existing international standards  require biodegradation of 60% within 180 days along with certain other criteria for the resin or product to be called compostable. It is important to make the distinction between degradable, biodegradable and compostable. These terms are often (incorrectly) used interchangeably.

 

Compostable Plastic is plastic which is “capable of undergoing biological decomposition in a compost site as part of an available program, such that the plastic is not visually distinguishable and breaks down to carbon dioxide, water, inorganic compounds, and biomass, at a rate consistent with known compostable materials (e.g. cellulose). and leaves no toxic residue.”  American Society for Testing & Materials (ASTM).  In order for a plastic to be called compostable, three criteria need to be met:

 

  1. Biodegrade – break down into carbon dioxide, water, biomass at the same rate as cellulose (paper).
  2. Disintegrate – the material is indistinguishable in the compost, that it is not visible and needs to be screened out
  3. Eco-toxicity – the biodegradation does not produce any toxic material and the compost can support plant growth.

 

Biodegradable Plastic is plastic which will degrade from the action of naturally occurring microorganism, such as bacteria, fungi etc. over a period of time.  Note, that there is no requirement for leaving “no toxic residue“, and as well as no requirement for the time it needs to take to biodegrade.

 

Degradable Plastic is plastic which will undergo a significant change in its chemical structure under specific environmental conditions resulting in a loss of some properties.  Please note that there is no requirement that the plastic has to be degrade from the action of “naturally occurring microorganism” or any of the other criteria required for compostable plastics.

 

A plastic therefore may be degradable but not biodegradable or it may be biodegradable but not compostable (that is, it breaks down too slowly to be called compostable or leaves toxic residue).

Product Home Composting Commercial Composting
Wheat Straw or Sugarcane Fiber  Plates, Takeout Contianers, Bowls, Cups and Trays Upto 6 months 1-3 Months
Ingeo Cold Cups, Clear Containers, Straws Not recommended 3-6 Months
TPLA Heat Resistant & Non Heat Resistant Utensils Not recommended 3-6 Months
Trash/Kitchen Bags Upto 1 year 2-4 Months

The rate of biodegration for different biocompostables is dependent upon the composition and thickness of the material as well as composting conditions. Commercial composting facilities grind the materials, turn over the piles and reach high temperatures, thus reducing the amount of time it takes to compost and, is thus, the recommended method for composting these products. Home composting rates are slower and can vary, depending on how frequently the pile is turned over, the moisture and material content and the temperature.   Composting utensils at home is not recommeded, due to their thickness and they may not break down for few years.  Similarlry, Ingeo products are not recommended to be composted at home.

There are currently few international organizations which have established standards and testing methods for compostability, namely:

The ASTM, CEN and DIN standards specify the criteria for biodegradation, disintegration and eco-toxicity for a plastic to be called compostable.

  • Biodegradability is determined by measuring the amount of CO2 produced over a certain time period by the biodegrading plastic.  The standards require 60% conversion of carbon into carbon dioxide within 180 days for resins made from single polymer and 90% conversion of carbon into carbon dioxide for co-polymers or polymer mixes.
  • Disintegration is measured by sieving the material to determine the biodegraded size and less than 10% should remain on a 2mm screen within 120 days.
  • Eco toxicity is measured by having concentrations of heavy metals below the limits set by the standards and by testing plant growth by mixing the compost with soil in different concentrations and comparing it with controlled compost.

In the long term, our society needs to substitute raw materials based on fossils (petroleum) with raw materials from renewable sources. Oil is a limited resource, the cost of which is rising due to increased global demand. The majority of our bags products are made from PLA, it is is an innovative family of bioplastics that uses substances obtained from plants, such as corn starch, and biodegradable/compostable polymers obtained both from renewable raw materials and fossil raw materials. PLA is the result of continuous efforts to use new technologies and new industrial supply chains based on the use of renewable energy and raw materials, while ensuring the highest levels of performance. The use of renewable raw materials, instead of those derived from fossils in the chemical and plastics industry, can help control greenhouse gases. These renewable raw materials use atmospheric CO2, absorbed by plants through photosynthesis.