Maybe you already have a reusable coffee mug or some vegan leather sandals. If you care for the environment, you may have investigated the new and improved compostable and biodegradable trash bags.
While compostable and biodegradable bags are a critical part of helping to sustain our beautiful Earth, there are some important distinctions to be made. These two are not the same type of trash bags, and in order to make the best choices for the environment, you'll need know a few things.
Below we’ll fill you in on the essential details about these two products, the best companies to follow, and the right way to use them.
Enjoy!
What's the Difference?
Compostable Trash Bags
Compostable trash bags consist of plant starch converted into bioplastics. Starch is easily broken down by microorganisms in soil and compost piles, just like any plant matter, and it does not produce toxic byproducts or contain petroleum-based plastics or heavy metals. These bags are intended to dissolve in a compost pile or, more often, in an industrial compost facility.
Biodegradable Trash Bags
Biodegradable trash bags come from petroleum-based plastic, so they feel and perform like a standard kitchen trash bag. But, unlike your classic trash bag, they are susceptible to digestion by the types of microorganisms living in landfills. These organisms break up the large chains of plastic into smaller chains of plastic.
At times, this is accomplished by the inclusion of heavy metals into the plastic. Some of the bacterial species thriving in the anaerobic landfill environment are those whose respiration depends on metals rather than oxygen, and they see these metal-infused plastics as a food source.
The Main Differences
The most critical distinction between these two types of bags is the label. “Compostable” is a government-regulated industry standard in both the U.S. and Europe.
Legally, this means that a product advertised under this label should break down under “compost conditions” into natural elements without leaving toxic byproducts in the soil within about 180 days.
The trick lies in the phrase “compost conditions,” which most people take to mean a home compost pile. In fact, for the purposes of labeling regulation, “compost conditions” means a high-temperature industrial compost facility.
The label “biodegradable” is entirely unregulated. Much like the label “natural,” it can mean almost anything an advertiser wants it to mean, rendering the label effectively meaningless.
How Quickly Do Compostable / Biodegradable Bags Degrade?
Biodegradable Trash Bags
In the presence of light, oxygen, and moisture, biodegradable trash bags may rot away within a few months. However, these conditions are rare.
Most of these bags find their way into a landfill, where light, air, and moisture are scarce. In this case, biodegradable trash bags break down no faster than standard trash bags. In a landfill, plastic is plastic!
Compostable Trash Bags
Any bag labeled "compostable" should deteriorate in a way similar to other plant matter within between 90-180 days if used as intended. Consumers may want to examine the label closely to make sure that the bag is marketed for “home use,” meaning it will break down without an industrial compost facility’s extreme heat.
In practice, many users find that the bags are markedly diminished but still visible in the compost pile after 180 days. In reality, it may take several seasons for bags to decompose fully. Lower pH and higher levels of moisture and heat accelerate the process.
Common Misunderstandings
Are Compostable / Biodegradable Bags Recyclable?
Neither compostable nor biodegradable trash bags are recyclable. They should be sorted into the general waste bin, or, in the case of compostable bags, used for compost material.
Do Compostable / Biodegradable Bags Break Down in Landfills?
While it seems evident that these bags would degrade more quickly in landfills than standard plastic bags, in fact, neither of them usually breaks down well in a landfill.
EPA regulations require landfills to block out most oxygen, moisture, and sunlight. Without these crucial elements, very little decay of any kind is happening inside a landfill.
Although they are not sterile environments (studies show that aerobic, anaerobic, and sulfur-reducing bacteria are all present), reactions occur so slowly that using a biodegradable trash bag is similar to using a standard trash bag.
Both will take decades or even centuries to break down under typical landfill conditions. Compostable trash bags decay slightly more quickly, although some studies have found them still completely intact in landfills after three years.
Can Compostable / Biodegradable Bags Harm the Environment?
All products labeled “compostable” or, even worse,“biodegradable,” can be environmentally problematic because of the phenomenon of “greenwashing.”
Customers spot a claim on a label that helps ease their concerns about damaging the environment. Rather than attempting to use the product as directed or, indeed, take future environmentally conscious actions, the consumer may do further damage, such as over-using trash bags or even littering with them.
On the contrary; they are still plastic and should be used only in the intended manner. When scattered as litter, biodegradable and compostable bags disintegrate faster under the sun, rain, and air than a standard trash bag would.
However, they still break into thousands of tiny plastic bits that are consumed by animals and incorporated into waterways. In fact, by crumbling quickly into so many small pieces, these bags actually may do more harm as litter as your standard plastic bag.
Are They Worth it?
The reality is, most brands just don’t deliver results that meet the expectation. Compostable bags have limited kitchen use (they don’t tolerate wet or heavy loads well), and biodegradable bags make empty promises.
With brand names like “EarthHero” and “If You Care,” these green-washed products push the environmental guilt hard. We recommend compostable bags.
At a minimum, compostable bag plastic is made from short-term carbons, and will dissolve quickly in the ocean (if that is where it ends up, as so much plastic does) into non-toxic bioplastics. Plus, when it (eventually) breaks down, it will make CO2 instead of methane, a more potent greenhouse gas.
Best Compostable Trash Bags
For Large Jobs
(Like Collecting Leaves and Yard Clippings)
Envision 33 Gallon Compostable Trash Bags
For Smaller Jobs
(Countertop Home
Operations)
ProGreen 2.3 Gallon Compostable
Trash Bags
Why These Brands?
Composting bags are generally not strong enough to hold heavy loads. They begin to dissolve under contact with any moist, acidic, or microbially-rich trash (think banana peels, old strawberries, coffee grounds, etc). While some brands may need to be changed every couple of days, the brands above are well-reviewed for having an above-average “lifespan.”
Before You Buy
In addition to its intended purpose of lining a kitchen composting bucket, a compostable trash bag will probably serve well in an area where it is changed frequently and holds dry, light loads, like under a desk or in a bathroom (especially if these loads are also compostable).
Although many composting bags come in a 13-gallon size, none are listed here. Since 13-gallon is a standard size for a regular kitchen trash, a composting bag used this way would end up in landfill -- not the practical or intended use for these bags.
Best Biodegradable Trash Bags
Trash Bags
Eco Smart 13 Gallon Trash Bags
Why This Brand?
Although some websites claim that Eco Smartbags are compostable, they are not. However, what makes these biodegradable bags interesting is their inclusion of a proprietary additive (recall that this may or may not include heavy metals).
This compound hastens the action of anaerobic bacteria in landfills; the company claims that a bag will decompose in a landfill within seven years (not third-party verified). If this is true, their “biodegradable” claim is more accurate than most.
Before You Buy
These bags are probably more appropriate for typical kitchen use, both because they claim to break down in a landfill (compostable bags won’t) and also because they can comfortably hold wet, heavy loads for long periods without the risk of breaking.
Conclusion
The next time you see the marketing labels “compostable” and “biodegradable” on the shelves, you will know the differences between them and when each one is best used. You’ll know what to expect, and you can make an informed decision for your particular needs.
If you have any questions or comments, please leave them below.
Cheers,
Caitlin
Would using a paper bag for kitchen waste be best? (With vegetable waste & coffee/tea grounds going in a separate compost bin)
Hi Sally,
Thanks for the response and great question!
Paper bags seem like a great option because they introduce less plastic into the environment. However, consider that paper holds up poorly to the levels of moisture that occur in most types of kitchen trash—even if you separate compost. Also, studies indicate that paper does not break down as quickly in a landfill as many people assume. Rather, like plastic, it takes many years for paper to degrade because the landfill environment is low in light, oxygen, and moisture. They also cost more and take up more space in a landfill because they are larger and heavier than plastic trash bags. Finally, a life-cycle study of paper bags shows that their manufacturing process emits more carbon and uses more water (about four times as much!) than manufacturing the equivalent number of plastic bags. Studies widely agree that plastic bags are less ecologically costly to manufacture than paper. Knowing this, choosing a trash bag is a question of your priorities. If it’s important to you to prevent plastic from entering the environment at any stage, paper bags may be a great option for you. If you take into account the whole life cycle of a trash bag, you might choose one of the plastic-based options discussed above. We think there are good reasons for doing both.
Here’s an report of the “life cycle of supermarket carrier bags”
Hope this helps!
Caitlin
Wow that was eye opening!
What's the best way collect garbage in a way that won't hurt the environment?
Hey Nao,
Thanks for the response and the great question.
Unfortunately we do not have the most environmentally friendly techniques for disposing of garbage. They’re better than a lot, but there’s plenty of room for improvement.
The best thing you can do at home is make sure you recycle and compost as much as possible. This will, in turn, make your trash contribution smaller and less detrimental. You can also use compostable bags for your trash. While this doesn’t promise a “fast” decomposition in a landfill, it will degrade faster than the traditional trash bags we use made of materials like high density polyethylene.
I know, not the most uplifting answer but these small changes (on a large scale) can have a significant impact on our footprint.
Hope this helps,
Michael
Do biodegradable bags or compostable bags that end up in a landfill release worse toxins as they break down than traditional plastic garbage bags?
Hi Lindsay,
Apologies for the delay!
Plastic consists of chains of carbon, which is not itself toxic, if plastic could be entirely broken down. Unfortunately, plastic mostly breaks down into very small, and very harmful, pieces known as micro plastics, which probably persist in the environment for thousands of years. Traditional (petroleum-based) plastic garbage bags break down into micro plastics very slowly in landfills (Wojnowska-Baryła et al., 2022). These micro plastics leach into the environment through the water supply and they accumulate as animals (including humans!) drink them or eat them in the form of plants.
Worse still, these micro plastics act as carriers of other harmful chemicals, such as heavy metals, pharmaceutical toxicants, per- and poly-flouoroalkyl substances (PFAS), and even pathogenic bacteria and viruses (Joo et al., 2021, Wojnowska-Baryła et al., 2022).
Several studies have confirmed confirmed that bioplastics, just like regular plastics, also release these harmful micro plastics at levels at least equaling that of traditional plastics. Moreover, they release micro plastics at a faster rate (Fan et al., 2022, Wei et al., 2021). There are also indications that the plant-based material portion of some bioplastics can release cytotoxic pollutants during brief stages of their breakdown.
On the other hand, a life-cycle study of bioplastics (Tabone et al., 2010) indicates that these bioplastics do indeed produce fewer greenhouse gas emissions as they break down in landfills compared to traditional plastics, since they are partially made from carbon-sequestering plants.
Long story short, there is hope, with scientific and processing advances, that bioplastics can be the answer to many of our plastic problems, but as it currently stands, the situation can be summarized by the authors of one of the aforementioned reports, who have concluded after deep study that “At present, the performance of bioplastics is worse than that of conventional plastics” (Fan et al. 2022).
Hope this helps!
Cait
References:
Fan, P., Yu, H., Xi, B., & Tan, W. (2022). A review on the occurrence and influence of biodegradable microplastics in soil ecosystems: Are biodegradable plastics substitute or threat? Environment International, 163, 107244. https://doi.org/10.1016/j.envint.2022.107244
Joo, S. H., Liang, Y., Kim, M., Byun, J., & Choi, H. (2021). Microplastics with adsorbed contaminants: Mechanisms and Treatment. Environmental Challenges, 3, 100042. https://doi.org/10.1016/j.envc.2021.100042
Tabone, M. D., Cregg, J. J., Beckman, E. J., & Landis, A. E. (2010). Sustainability Metrics: Life Cycle Assessment and Green Design in Polymers. Environmental Science & Technology, 44(21), 8264–8269. https://doi.org/10.1021/es101640n
Wei, X.-F., Bohlén, M., Lindblad, C., Hedenqvist, M., & Hakonen, A. (2021). Microplastics generated from a biodegradable plastic in freshwater and seawater. Water Research, 198, 117123. https://doi.org/10.1016/j.watres.2021.117123
Wojnowska-Baryła, I., Bernat, K., & Zaborowska, M. (2022). Plastic Waste Degradation in Landfill Conditions: The Problem with Microplastics, and Their Direct and Indirect Environmental Effects. International Journal of Environmental Research and Public Health, 19(20), 13223. https://doi.org/10.3390/ijerph192013223
Thank you for this informative article! Do you have any recommendations for doggy poop bags?
Hey Savannah, I recommend finding bags that are D6400 & EN13432 certified, which basically is the US and Europe’s promise that the bag will degrade in an industrial compost setting (within a certain time frame). This is if you plan to throw the bags in your city compost bins. If you plan to compost the bags at home, look for the label “OK Compost Home”.
“Compost at Home” Poops Bags
City Compost Bin Dog Poop Bags
Please let us know if there’s anything else we can do for you 🙂
Savannah,
We like these doggie poop bags. They are certifed compostable so I feel good that they break down well: https://greenpaperproducts.com/biodegradable-dog-poop-bags-cbd864.aspx
Thank you! Very informative.