Is HDPE biodegradable? (7 properties of HDPE) 

In this article, the biodegradability of HDPE will be questioned. Other covered aspects will be: 

  • What is HDPE?
  • What are the types of plastics?
  • How is HDPE for the environment?
  • What is biodegradability?
  • What are the impacts of non-biodegradable waste on the environment?
  • Is HDPE biodegradable?
  • Can HDPE be recycled?
  • FAQs

Is HDPE biodegradable?

HDPE is not biodegradable because it is made from fossil fuel derivatives. It may require 450 years to degrade. 

However, HDPE is regarded as a safe plastic because its products are safe and non-toxic and may be used for applications such as jugs, grocery bags, kitchen bottles et cetera. 

HDPE can be recycled into new products and in this way, the negative effects of HDPE waste on the environment can at least be delayed to varying extents. 

What is HDPE? (7 properties of HDPE) 

HDPE expands to High-Density Polyethylene. HDPE is a synthetic polymer which is used to make consumer products. The products made from HDPE may include: 

  • Toys
  • Containers
  • Shampoo bottles
  • Grocery bags
  • Recycling bins
  • Jugs
  • Pipe systems

There are two types of polymers in the world. One is natural and the other type is synthetic polymers. The word polymer is of Greek origin which means many parts. 

Polymers are made from repeating monomers that are connected by chemical bonds such as covalent bonds. 

Examples of natural polymers include nucleic acids like DNA or RNA, proteins et cetera. The impact of natural polymers is supposed to be minimal because these polymers are found in nature. 

Examples of non-natural polymers include synthetic plastics like PET, LDPE, PVC, PC et cetera. The environmental impact of synthetic polymers is considered significant because of the fact that these polymers are made at the expense of fossil fuels. 

HDPE is an example of synthetic polymers and therefore, it is plausible to assume that there will be effects of HDPE on the environment and human health and that these effects will not be good. 

The article will also question the biodegradability status of HDPE because biodegradability is also a very important checkpoint because non-biodegradable products have a lot of negative impacts on the environment and human health. 

The following are the properties of HDPE: 

  • Translucent
  • Strength
  • Resistant to chemical
  • Water-resistant
  • Low absorption 
  • Affordable 
  • Easy processing 

What are the types of plastic?

As said, there are various types of plastics. HDPE is just one type of plastic. Other types of plastics commonly found in the consumer marketplace include: 

  • PET
  • LDPE
  • PVC
  • PC
  • PLA
  • Contemporary plastics 

Out of all these, most of the plastics are made from products derived from fossil fuels, and therefore, most of the plastics are non-biodegradable. 

The last category of plastics include bioplastics which are made from natural, plant-based materials. Examples of such materials can be sugarcane or cornstarch. 

You may wonder why there are so many types of plastics. The primary reason is because of the diverse use and applications of plastics. 

Plastics are found everywhere around us. From food to packaging to toys, every industry is associated with the use of plastic in its products. 

That is why we have different categories of plastics that are used for specific purposes. For example, bottles are mostly made from PET plastic. 

As per HDPE, the products that use HDPE include toys, containers, jugs, bags, box liners et cetera. 

Owing to the diverse properties of HDPE such as chemical and water resistance, affordability, and mechanical strength, it is used in a plethora of commercial and consumer products delivering good utility overall. 

How is HDPE for the environment? 

HDPE is a synthetic polymer and therefore, there are a number of negative impacts of HDPE on the environment. 

The greatest impact of HDPE on the environment is because HDPE is not biodegradable. It is also not compostable. 

Owing to this, HDPE will remain in the environment for hundreds of years. It is argued that HDPE may take as long as 450 years to degrade. 

While it persists, it may cause a number of environmental problems as well. HDPE production makes use of products derived from fossil fuels and this process leads to the emission of Greenhouse gases.

GHGs are known to cause a lot of harm to the environment because they cause a global rise in temperature which is also known as global warming. Global warming leads to other environmental problems as well that may include: 

  • Rising global temperatures
  • Floods
  • Droughts
  • Unseen weather patterns
  • Melting of glaciers
  • Pest and insect attacks
  • Loss of crop
  • Destruction of ecosystem
  • Disruption of food chains 

However, it may also be argued that HDPE is considered a safe option among other types of plastics. You may argue it is the best among the least. 

The production process of HDPE is relatively less intense as compared to other synthetic polymers. For example, HDPE making may require only a fraction of energy as compared to steel production. 

Furthermore, the products obtained from HDPE are regarded as safe and non-toxic and that is why they are used as food containers as well. 

What is biodegradability?

In order to make a stance on the biodegradability of HDPE, it is also important to know what biodegradability is. Biodegradability is the breakdown of waste by the action of microbes. 

These microbes can be bacteria, fungi, decomposers, algae, and even protozoa. These microbes ensure that the waste generated does not accumulate and gets back to the system of life. 

That is because if there is waste accumulation, there will be negative effects of that waste accumulation which will impact all areas of our life. 

Therefore, biodegradability can also be regarded as nature’s dustbin. What is the role of a dustbin? To keep the waste segregated from the environment and make sure it does not pollute the environment. 

The role of biodegradability is very similar. Other than microbes, there are also external factors which play an important role in the biodegradation process. These may include aeration, sunlight, temperature and pressure. 

The time taken for a product or substance to biodegrade depends on the type of material and the external conditions. 

Based on biodegradability, there is a classification of waste. Waste may either be biodegradable or non-biodegradable. 

This is because not all waste can be degraded by the action of microbes. Most of the waste that is from synthetic materials produced at the expense of chemicals and human innovation is not biodegradable. 

It may take hundreds of years for such waste to degrade and therefore, it is termed non-biodegradable waste. Examples of non-biodegradable waste may include:

  • Epoxy resin
  • PET
  • LDPE
  • Nylon
  • Dyneema
  • Acrylic fabric
  • Synthetic resins

These materials may take from a few hundred years to a thousand years to degrade. While they persist, they cause a plethora of problems to the environment and life. Examples of biodegradable waste may include plant waste, animal waste, manure et cetera. 

The impact of biodegradable waste on the environment is very less compared to non-biodegradable waste.

What are the impacts of non-biodegradable products?

The following are the common impacts caused by non-biodegradable products on the environment and human health: 

  • Global warming
  • Melting of glaciers
  • Increased sea levels
  • Deforestation
  • Decreased tree count
  • Decreased air quality
  • Poor fertility of the soil
  • Loss of life
  • Disruption of ecosystem
  • Chance in the natural habitats
  • Destruction of the natural order

The effects of non-biodegradable waste are not just limited to the environment. They are also reciprocated in life as well. Including humans, all forms of life are affected and impacted by the occurrence of non-biodegradable waste. 

These effects may include: 

  • Necrosis 
  • Organ damage
  • Developmental issues
  • Hormone change
  • Neuro Complications
  • Neuro toxicity 
  • Cancer
  • Mutations
  • Skin diseases
  • Behavioural changes
  • Damages to the foetus 

Is HDPE biodegradable?

It has been assessed that for a product to be biodegradable, it must be made from natural materials. We have seen the various categories of plastics and among those, only type 7 plastics (contemporary plastics made from plants) are biodegradable.

HDPE is not biodegradable because it is not sourced from nature; rather it is a product of fossil fuel derivatives. 

HDPE will remain in the environment for hundreds of years. It is estimated that HDPE may remain in landfills for as long as 450 years. 

Other than being non-biodegradable, HDPE is also non-compostable. Compost is dead organic matter which may be used as a natural fertiliser. 

Can HDPE be recycled?

Recycling is the process of reusing waste by converting and processing the waste into new materials. Recycling is one of the best solutions to deal with non-biodegradable waste. 

Since HDPE is not biodegradable, the next genuine question is whether it is recyclable or not.

Fortunately, HDPE can be recycled into new products and in this way, the negative effects of HDPE waste on the environment can at least be delayed to varying extents. 

Other benefits of recycling include:

  • Waste management
  • Resource management 
  • Resource conservation 
  • Reduction of waste generation 
  • Reduced pollution and other negative impacts of non-biodegradable waste 

Conclusion

It is concluded that HDPE is not biodegradable because it is made from fossil fuel derivatives. It may require 450 years to degrade. 

However, HDPE is regarded as a safe plastic because its products are safe and non-toxic and may be used for applications such as jugs, grocery bags, kitchen bottles et cetera. 

HDPE can be recycled into new products and in this way, the negative effects of HDPE waste on the environment can at least be delayed to varied extents. 

Frequently Asked Questions: Is HDPE biodegradable?

How long does it take for HDPE to degrade?

It may require 450 years for HDPE to degrade.

Which type of plastic is biodegradable?

Bioplastics made from sugarcane or corn starch are biodegradable. 

References

  • Achilias, D. S., Roupakias, C., Megalokonomos, P., Lappas, A. A., & Antonakou, Ε. V. (2007). Chemical recycling of plastic wastes made from polyethylene (LDPE and HDPE) and polypropylene (PP). Journal of hazardous materials, 149(3), 536-542.
  • Al Bakri, A. M., Tamizi, S. M., Rafiza, A. R., & Zarina, Y. (2011). Investigation of HDPE plastic waste aggregate on the properties of concrete. Journal of Asian Scientific Research, 1(7), 340-345.
  • Bardají, D. K. R., Moretto, J. A. S., Furlan, J. P. R., & Stehling, E. G. (2020). A mini-review: current advances in polyethylene biodegradation. World Journal of Microbiology and Biotechnology, 36(2), 1-10.
  • Balasubramanian, V., Natarajan, K., Hemambika, B., Ramesh, N., Sumathi, C. S., Kottaimuthu, R., & Rajesh Kannan, V. (2010). High‐density polyethylene (HDPE)‐degrading potential bacteria from marine ecosystem of Gulf of Mannar, India. Letters in applied microbiology, 51(2), 205-211.

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