What happens to glass when you throw it away?


When you throw away glass it either ends up in a landfill, in a ditch or in a recycling plant depending on where and how you throw it away. Glass is for the most part very recyclable but not all glass, for example lamp bulbs and wine glass consists of different kind of glass.

In this article you will learn about the lifecycle of glass and how exactly glass is recycled. What the numbers are and what you can do to recycle glass properly.

Also some alternative tips that you can use to avoid throwing away glass because recycling isn’t zero waste. Always remember that is costs energy to recycle and therefore recycling also releases greenhouse gasses in the process.

The lifecycle of glass

First of all, let’s dive in a little more on what glass is and how it’s made. Check out this video made by the company Saint-Gobain:

Basically they explain that glass has a lifecycle of 6 stages:

  1. Extraction of raw materials
  2. Manufacturing of flat glass
  3. Transformation (shaping the glass)
  4. Construction or consuming
  5. Glazing life
  6. End of life

For the extraction of raw materials mainly sand and water is used and something called soda ash which is natrium carbonite and it reduces the melting temperatures and supports the shaping of glass.

The raw materials are shipped to factories that are called floats where they are melted in large kilns in temperatures of around 1500 degrees. Then they are coated to make stronger. After this process flat glass is created.

The flat glass is moved to a transformation factory where it is shaped into what ever is needed. Bottles, windows, pot lids.

Then the glass is shipped to the consumer, a company or a construction site.

The glazing life is the time it is being used. This can also mean reuse.

End of life is when it’s time to throw away or recycling.

Glass recycling in numbers

According to Statista the glass industry reported recycling around 27 million metric tons worldwide, which is 21% of the total glass production in that year. This does not mean 21% of glass is recycled though. Container glass accounted for the highest recycling rate amoung glass, with around 32% waste.

Volume recycled (in million metric tons)27
Percentage of glass produced that is recycled21
Recycling rate (in percentage)*35
Recycling rate of container glass (in percentage)32
Recycling rate of flat glass (in percentage)11

How glass is recycled

Glass is recycled by the following process:

Step 1: The glass is stripped from labels and other items.
Step 2: The glass is broken down
Step 3: The glass is melted
Step 4: The glass is being poured into a mold.

Important takeaways:

  • Always categorize your glass by color.
  • Glass has be broken because it melts faster.

Recylable glass and non recyclable glass

Mostly container glass is recylable. Think of glass bottles, jars, drinkware and bowls. What isn’t recyclable is glass with items attached or mixed into it like lightbulbs, car glass and wine glasses.

The positives of recycling glass

Despite the fact that recycling costs energy and releases pollutants it still is better for the environment overal. It reduces related air pollution by 20% and related water pollution by 50%.

Also recycling glass as with almost all recycling reduces the amount of landfills and that means less toxic materials end up in soil and in (drink) water.

The cost savings is in the use of energy. Compared to making glass from raw materials, cullets melt at lower temperature.

Source: https://wwf.panda.org/discover/knowledge_hub/teacher_resources/project_ideas/recycling_glass/?

The negatives of recycling glass

The disadvantages of recycling glass are that of recycling overall but not all. They are:

  • While being processed the factories do produce green house gasses.
  • Not all glass items are recyclable.
  • Glass recycling creates unemployment because there will be less jobs in the glass industry.

Now ofcourse everything has a down side but glass recycling is much much better than throwing it away. Reducing the amount of landfills is very important in order to combat climate change.

Reusing glass is always better when possible

If possible you should re use your glass if at all possible. For example if you want to throw away wine glasses think about selling them instead of throwing it away. Now ofcourse this isn’t possible for all glass, but be mindful if this is at all possible. Now that you also know that not all glass is recyclable.

Would you like to know what happens to other materials different then glass? Check out our other article about most household items and what happens to them when you throw it away here: https://greennova.net/where-does-your-trash-go-after-you-throw-it-away/

Sources used:

  • https://www.recovery-worldwide.com/en/artikel/glass-recycling-current-market-trends_3248774.html
  • https://www.statista.com/statistics/1055604/key-figures-glass-recycling-globally/.
  • https://wwf.panda.org/discover/knowledge_hub/teacher_resources/project_ideas/recycling_glass/?
  • https://www.youtube.com/watch?v=vhpc0UULjDU
  • https://www.youtube.com/watch?v=MOKT6crXtFE
  • https://www.ciner.us.com/soda-ash-spotlight-the-glass-manufacturing-industry/#:~:text=Specifically%2C%20soda%20ash%20is%20used,shaping%20of%20the%20glass%20item.
  • https://en.wikipedia.org/wiki/Container_glass

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Greennova is created out of a passion for sustainability. The vision is to create a sustainable world for humans and our role is to provide a platform where people can learn about how to become part of the solution.

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