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Defining Biodegradable and Comparing to Compostable

written by: ciel s cantoria•edited by: BStone•updated: 8/8/2010

Finding out exactly what does biodegradable mean vs. compostable can help individuals make their own contributions to resolve the current waste management problems faced by their communities. Find out how and why...

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    The Complex Problems of Solid Waste Management

    800px-Solid waste in plastic barrels 

    One of the complexities in waste disposal is the presence of solid waste materials and their decomposition structures. Currently, not all consumers have sufficient knowledge pertaining to biodegradable vs. compostable wastes. There is very little awareness of the fact that not all of the biodegradable products being bought and used provide solutions to present environmental troubles.

    In fact, consumers in general are of the mindset that adding biodegradable wastes to the waste stream is harmless. Unfortunately, the presence of unscrupulous manufacturers have added to this complexity, by making improper or incorrect use of the descriptions “biodegradable" or “compostable" in their product labels.

    In view of this, it is quite important that consumers are well informed about the distinction between the two terms. However, answers to the question "What does biodegradable mean ?" goes beyond an understanding of the definition but should also delve into how the two types of materials overlap.

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    What Is Biodegradable?

    800px-Shredded solid waste 

    Most scientific publications admit that there have been many attempts to define biodegradation. Nevertheless, all agree that it is in essence the natural property of a material to transform into something undesirable due to the activities of microbial organisms.

    In the earlier days of waste management, this process was called biodeterioration.

    The word biodegradation came into use when the need for waste management became of utmost importance, because modern living introduced other materials made from synthetic substances that could not assume a natural state of deterioration. These materials were then assigned the classification of non-biodegradables.

    A material is coined non-biodegradable if it does not possess the quality of deteriorating through natural processes brought by the conditions of moisture and heat plus the feeding activities of a microbial community like bacteria, algae, fungi and yeast. The enzymes of these organisms are supposed to cause the original form of the material to disappear and be converted into other compounds, particularly carbon dioxide.

    As a result, solid waste management units' solution was to segregate non-biodegradables from the biodegradables.

    As years passed more testing processes were conducted and as more products were introduced, things became complicated. The environmental problems that were revealed demanded more than the simple solution of differentiating biodegradables from non-biodegradables.

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    The Problems with Some Biodegradable Wastes as Composting Substances

    450px-Composting together 

    Carbon dioxide is essential to plant life; hence, the idea of composting became of great relevance to biodegradable substances.

    However, since plastics and genetically modified food came into the picture, further testing made by the American Society for Testing and Materials revealed that not all biodegradable materials, particularly plastics, deteriorate at the same rate. Its not just about what does biodegradable mean, but what are the specific properties of each type of biodegradable substance. Also to consider, some wastes do not produce similar by-products as natural wastes. This realization brought awareness that large amounts of carbon dioxide and other substances are being released into the environment as substances break down, causing further pollution to land, water and atmosphere.

    The following are the problems caused by biodegradable wastes:

    • The U.S. EPA includes some biodegradable materials as causes of pollution. Although these wastes are broken down, they transform into another compound, usually organic carbon, which subsequently converts into carbon dioxide and water. Through a series of natural processes, carbon dioxide will form part of the atmosphere and precipitates into acid rain.
    • Another problem presented by biodegradable wastes is that their large presence in bodies of water and subsequent conversion into organic carbon can promote the presence of oxygen consuming organisms. These types of organisms tend to compete with other marine life in the consumption of oxygen content available in their habitats, as in the case of a great part of the Gulf of Mexico declared as a “dead zone". It was established that this area was no longer inhabitable by aquatic life due to its low levels of oxygen.
    • Others may think that this is of little importance but the greater impact, if cases like this will continue, is the eventual loss of biodiversity, considering those instances when thousands of dead fish often rise to the surface due to unexplained causes.
    • Fertilizers made from sewage sludge are considered as unfit for organic gardening due to the possible presence of human wastes carrying food substances broken down from genetically modified food.

    Please proceed to the next page to know the succeeding developments to these environmental problems.

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    After learning the answer to "what does biodegradable mean?", learn about the differences and similarities in biodegradable and compostable wastes, so you can make informed decisions. In addition, find information on where to check for compostable and non-compostable organic materials as well as where to check out products that are genuinely certified as compostable.
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    How Does a Biodegradable Material Compare to a Compostable Substance?

    Perhaps, at this point the reader now has an idea about the differences between biodegradable vs. compostable. Nevertheless, the key differences are presented in the list below:

    (1) Biodegradables can only be broken down into useful materials through a commercial facility equipped and constructed for such purpose. Compostables can be included in your home compost, and will transform into a humus-like substance within a reasonable time frame. It usually takes 3 weeks, and will become usable as fertilizer or soil augmentation.

    (2) Biodegradable products contain petroleum based ingredients while compostable materials are made from natural plant fibers like bamboo, crop stalks and starches.

    (3) Biodegradable material will decompose by way of microbial processes, but the length of time it takes to decompose and the condition required varies. Compostable wastes can be expected to transform into useful humus within the same period that it takes natural matters like food, grass, dried leaves and other wastes made from similar materials when put into ordinary home composting processes.

    (4) Both types of waste, if put together with other garbage material in a landfill, will not breakdown. Both have to go through their respective processes in order to become useful.

    (5) Both biodegradable and compostable plastics are not recommended for home composting because they are capable of emitting methane.

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    What Steps are Being Taken by Local Government Units to Resolve this Problem?

    120px-Material recovery facility 2004-03-24 

      With these issues to consider, some local governments no longer accept wastes that are classified as biodegradables, but only those that are considered as compostable. The issue here is the amount of money spent to manage solid wastes and that local government units do no have the funds to spend for sorting biodegradables nor the composting facility to break them down.

      The city of Wyoming for example does not accept biodegradables, compostable or not. They maintain that the city’s composting facility does not have the capacity to convert biodegradables into suitable compost materials. The compostable plastics are also banned because a large concentration of these wastes will pile up in landfills. They foresee that the strong Wyoming winds will only carry the broken down chemical compositions of disintegrated plastics and other compostable waste materials into the air. These now are some of the present-day complexities of solid waste management problems.

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      MSWghg co2 emission 

      After defining biodegradation and comparing the process to composting, a recap of what has been discussed will draw us into a conclusion that solid waste management’s initial recommendation of segregating garbage into biodegradables and non-biodegradables was not sufficient to address waste disposition problems. Although some of the non-biodegradables were reclaimed, repurposed or recycled, certain environmental problems stemmed from biodegradation as it produces carbon dioxide.

      As carbon dioxide is essential to plant life, composting became the recommended waste treatment process in households and in municipal levels. However, as more sophisticated methods of testing processes were developed, it revealed that not all biodegradable wastes are fit for composting. The time and condition it takes for most biodegradables vary; hence local solid waste management units have to spend considerable amounts just to segregate biodegradables into those that are fit for composting and those that are not. In addition, their facilities have to be outfitted with composting processors that can immediately convert biodegradables into compost material.

      Based on all that transpired, it appears that the main issue here is that local government units are spending funds that could be directed elsewhere, instead using them to manage a continuous flow of biodegradables. It seems that the only solution left for solid waste management is total waste reduction and elimination.

      During the recent Earth Day celebration, the National Solid Waste Management Association, a for-profit trade association of North American professionals, along with other waste management companies, vowed to achieve zero-waste by investing more on technology.

      Perhaps if more consumers are aware of this problem, then they can contribute in their own way to eliminate such wastes by totally eliminating biodegradables from their shopping lists. Hence, there will be less demand for new technologies. In view of this, you may want to check on the Environmental Protective Agency’s list of compostable and non-compostable organic materials.

      Now that you know the answer to the query "What does biodegradable mean?", it would be best if you know what are the compostable consumer products. They can be checked with the Biodegradable Products Institute (BPI) by referring to their Directory of Certified Compostable Products. In addition, products labeled as “compostable" should bear the BPI Logo.

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      Reference Materials and Image Section

      Reference Materials:



      • Wikimedia Commons