Is glass recyclable?

Glass is a transparent solid which is made primarily from molten sand. It’s a non-crystalline substance which we use for a multitude of purposes. It’s used to make containers, windows, decorations, and many other household items. 

In this article, I will go over whether glass is recyclable. Then I will explain in detail what glass is made of. Thereafter I will explain the process of recycling glass. Lastly, I will discuss the obstacles we face in glass recycling today. 

Can we recycle Glass? 

Yes, glass is a resource that can be endlessly recycled without any drop in quality. It is 100% recyclable. Glass is made from silica (SiO2), soda ash, and lime mixed with certain other raw materials. Cullet is the name given to recycled or broken glass which is a major ingredient of glass-making. 

In most cases, 95% of the cullet is mixed with 5% other raw material to make glass. 

This significantly reduces the energy expenditure of the factory since using cullet reduces the temperature at which glass is melted. 

Moreover, using cullet drastically cuts down on greenhouse gas emissions during the glass-making process. Soda ash, also known as Na2CO3 releases CO2 when heated. Using prominently cullet to make glass means less soda ash is added, thus less CO2 is released into the atmosphere. 

One more advantage of recycling glass is that it’s cheaper than making new glass. Since less raw materials and energy are required, it’s more cost-effective and the more environmentally friendly option.

It is important to know which glass objects are recyclable and which are not. Indiscriminately dumping all glass into the recycling bin will contaminate the source and may result in the entire batch being thrown into landfills. 

Almost all glass that is used for food packaging is recyclable, which includes drink bottles, glass food containers, jars, etc. The recycling plant will sort these based on color and it is not necessary to sort them beforehand. 

However, there are glass items that are not recyclable, and there are different methods of disposal for them.  These glass items are light bulbs, fluorescent light tubes, mirrors, window glass, pyrex glass, crystal glass, drinking glasses, etc. 

The disposal methods for these items vary and will be discussed in detail in the next section. 

How to dispose of non-recyclable glass: 

Not all glass can be thrown in the household recycling bin. 

Fluorescent lights, for example, have hazardous chemicals inside, which you should either take to a household hazardous waste facility (HHW) or wait for a recycling event to drop them off. Some countries leave recycling points around the city where you can drop those off. 

Other lights like incandescent and halogen lights go in the trash. 

Drinking glasses like wine or water glasses have a very different chemical composition and melting point, if these are mixed with recyclable glass then the end product is of poor quality. They usually have fracture points and abnormalities in the end product making them unreliable for future use. 

If drinking glasses are broken, please place them in a paper bag before throwing them in the trash, intact glasses can be repurposed or donated. 

Broken glass is fairly controversial in many countries. The problem with broken glass is that it’s a health hazard and can injure the staff who work to collect the recyclable items or work at the recycling plant. 

Most municipalities do not accept broken glass but check your municipality’s rules on broken glass before you throw them out.

The best way to dispose of broken glass is to first wrap them in a paper bag, please keep in mind throwing them in a plastic bag is a very dangerous health hazard for municipal workers. 

Another important reminder is that ceramic is not recyclable. It is not glass, even though it gets mistaken as glass in many cases. Ceramic should be thrown in the garbage or given away. 

On top of that, broken glass of different colors contaminates the entire batch, colored glasses mixing would ruin the aesthetic quality of the glass. And it is extremely hard and dangerous to sort broken glass. 

Pyrex, mirrors, window glasses are all non-recyclable. Pyrex is treated with special chemicals to be able to withstand high temperatures, that is why it can’t be recycled. 

You can dispose of these glasses in the garbage, but there are local programs that repurpose mirrors and window glasses into construction material. Check your local companies before you throw them out. 

Depending on where you are, how you recycle glass will vary. Make sure you know the local regulations. 

The process of recycling glass is fairly straightforward and closely resembles the recycling process of plastic and paper. The process is explained in detail in the next section. 

How do we recycle glass? 

Most European countries have a multi-stream recycling system where there are multiple bins each assigned to a specific material, i.e. glass, paper, plastic, metal, etc. However, in the United States, the recycling system they follow is single-stream, which means all recyclable material is thrown into the same bin. 

Glass collected from a single-stream recycling system has to undergo a few extra steps of processing since it’s mixed in with all types of recyclable material. 

First, it needs to be sorted and collected to remove all other impurities from the batch. Once that is done it is sent to a Materials Recycling Facility (MRF) where it is stored until it’s sent to a glass treatment plant. 

For the glass collected via a multi-stream recycling system, glass is directly sent to the MRF. 

In the glass treatment plant, cullet is made. Glass recycling has 5 main steps, as explained below: 

  • Color sorting- glass is first sorted by color. In most countries, it’s done by a machine and the process is fully mechanized. The glass containers are sorted according to three colors, clear, green, and brown.
  • In this step, the glass is crushed mechanically. This produces cullet, which is crushed glass. This cullet is then sent to a beneficiant plant.
  • Beneficiation is the process by which contaminants are removed from cullet. A magnet is used to remove the iron particles, an air jet is used to blow away non-iron metals. Then a vacuum is used to remove lightweight contaminants, lastly, a laser is used to remove any remaining contaminants from the cullet.
  • Now, this cullet is melted and molded to give new shapes and sent to factories for food and drink packaging. 

Problems facing the glass recycling industry today:

Most European countries are role models when it comes to recycling and sustainable living.  On average, Europe recycles 74% of its waste glass. 

Compared to this impressive number, the United States falls short. In the US, only 33% of its waste glass is recycled currently. The main reason behind this abysmal number is the Single-stream recycling system. 

A lack of awareness among the public regarding recycling is also a factor. Many Americans do not bother to recycle their glass waste, these end up in landfills. 

Moreover, many well-intentioned folks throw many non-recyclables like batteries, composite material into curbside recycling bins which contaminate the whole batch. Consequently, all these items again end up in landfills. 

Glass takes 4000 to 1 million years to decompose, this imposes a serious threat to the ecosystem. In many countries in the developing world, inefficient disposal and recycling systems mean glass ends up in the soil, and water outside of landfills.

This is a major health hazard in places where underprivileged people live around landfills and scavenge landfills for valuables. 

Better disposal systems have to be implemented to curb glass ending up in landfills in these areas. A proper recycling system for glass benefits all parties, it has environmental and economical benefits over making new glass. 

The European model has worked for decades now, and it seems to be the best way to save natural resources and limit the excess carbon emissions, both of which are associated with new glass making. 

One reason why recycling works so well in Europe is that children in school are taught the importance of it, and the proper procedures of recycling. This seems to be the way forward for the rest of the world. 

Conclusion: 

In this article, I went over whether glass is recyclable. Then I explained in detail what glass is made of. Thereafter I explained the process of recycling glass. Lastly, I discussed the obstacles we face in glass recycling today. 

Frequently Asked Questions (FAQ): Is glass recyclable? 

Is glass recyclable or not? 

Yes, glass is one of the resources that is endlessly recyclable. It cannot be recycled infinitely without any drop in quality. 

Can glass be 100% recycled?

Yes, 100% of the glass that’s sent for recycling is used. Glass, if recycled responsibly will not end up in landfills. 

What types of glass are not recyclable? 

Although most glass is recyclable, some are not, these include mirrors, drinking glasses, window glass, light bulbs, fluorescent tubes, etc.

It’s wise to check your municipality’s instructions on glass recycling for more accurate information. 

What is the rule when recycling glass? 

As a general rule of thumb, recycle bottles and jars. Make sure you don’t throw broken glass into the recycling bin. Those are hazardous. Refer to the question above to see which glass items cannot be recycled.  

Is broken glass recyclable? 

It depends. It is always preferred that the glass isn’t broken. There are some multi-stream recycling systems in certain European countries where they accept broken glass. But in countries like the US where the recycling system is single-stream, broken glass is not recyclable. 

References: 

  1. Glass Recycling Facts – Glass Packaging Institute. (2021). Retrieved 9 December 2021, from https://www.gpi.org/glass-recycling-facts
  2. (2021). Retrieved 9 December 2021, from https://www.randysenvironmentalservices.com/about/blog/glass-101-what-types-glass-can-be-recycled
  1. Glass 101: What types of glass can be recycled?. (2021). Retrieved 10 December 2021, from https://www.randysenvironmentalservices.com/about/blog/glass-101-what-types-glass-can-be-recycled
  2. Deer, R. (2021). Why is Glass Recycling Going Away?. Retrieved 9 December 2021, from https://www.roadrunnerwm.com/blog/why-is-glass-recycling-going-away
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  4. Glass Recycling – SUEZ Australia & New Zealand. (2021). Retrieved 9 December 2021, from https://www.suez.com.au/en-au/sustainability-tips/learn-about-waste-streams/general-waste-streams/glass-recycling
  5. The Glass Recycling Process | How is Glass Recycled?. (2021). Retrieved 9 December 2021, from https://gaskellswaste.co.uk/recycling/glass-reprocessor/
  6. The Glass Recycling Problem: What’s Behind It, and What to do. (2021). Retrieved 9 December 2021, from https://greatforest.com/sustainability101/the-glass-recycling-problem/
  7. Glass Recycling. (2021). Retrieved 9 December 2021, from https://www.calrecycle.ca.gov/glass
  8. Is Glass Recyclable?. (2021). Retrieved 9 December 2021, from https://pebblemag.com/magazine/living/is-glass-recyclable

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