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The lifecycle of glass

by Sharné

According to Consol, South Africa consumes more than 3.1 million tonnes of glass a year, 66% of which is reusable. The Glass Recycling Company (TGRC) states that we recycle 44% of the glass we use.

I admit, I used to think recycling was one of the most powerful, planet-friendly actions I was doing as an eco-conscious consumer! Before going #zerowaste I would buy items that were recyclable, and justify the purchases based on the fact that the items are recyclable. I would then recycle the items after a single use.

Then I discovered that to truly make a difference recycling should not be the first step after purchase, but a last resort! This goes for all types of recyclables, but for this post I’m focussing on glass.

Reuse, reduce then recycle

We currently have over 4000 glass banks in South Africa, which is amazing because it does make recycling more accessible. But recycling is just another way, albeit a more environmentally friendly way, of throwing out your waste. We really need to shift our focus from recycling to reducing in order to truly make a positive impact on the environment! And we need to reuse what we have reduced in order to prolong the lifespan of the items already made, which reduces the items carbon and ecological footprint.

To understand why this approach is better, we need to look at how glass is made and how it is recycled. With any product, to truly understand it’s environmental impact we need to look at it’s entire lifespan from extracting the materials needed to make the product, all the way to what happens to the product after use ie. recycling.

The ingredients of glass

Glass is made by melting minerals together at incredibly high temperatures. But first Silica, a type of sand and other materials like limestone and soda ash, all of which are natural materials, are extracted from the earth. To make coloured glass different types of oxides are added.

I have to note that these materials are finite aka non-renewable, yet we are using up earths resources as if it is infinite. The mining of these materials lead to land degradation, pollution, loss of biodiversity but also causes further environmental damage.

Once the materials are extracted, they are then processed which requires an immense amount of water and energy. Then the materials are transported from various countries to the glass making facility. Transportation in itself causes environmental damage.

Manufacturing Glass

Once at the glass manufacturing facility, giant furnaces are used to melt the materials, at incredibly high temperatures (around 1,500°C), most often using fossil fuels as energy. These furnaces run 24/7, and are never switched off during their approximate 15 year lifetime. Water is using extensively throughout the process, specifically for cleaning, cooling and glass finishing processes.

According to Consol, when molten glass comes out the furnace it is cooled to 1200°C. and is then cut into gobs which are then fed into to moulds and using various methods, shapes like bottles or jars are created. Then the new shape is coated with tin oxide, which strengthens it, before being transferred to another oven, this one slowly cools the glass from 600°C to 100°C.

Once cooled the external surface of the glass item is coated in polyethylene wax which protects the surface of the glass and prevents scuffing between bottles.

During the glass manufacturing process there are a few key areas of environmental damage to note: emissions to air, waste water and solid waste.

Once the glass products are made, they are transported to various suppliers. In South Africa, there are many imported glass products not just locally made ones. Because glass is a heavy material, less is transported than would be for a lighter material. Buying locally made items will have a smaller transport carbon footprint than imported items.

Reusing glass

When I consider the negative environmental impact a single glass item like a jar already has made even before purchase, then I’m encouraged to try reuse that jar for the rest of my life, if possible. I have a house full of jars, that was once filled with food, that is now being used in the garage, craft room, medicine cabinet and in the kitchen pantry, to store my packaging free dry goods. And the ones I don’t use I try to donate to others who can use it. And if that’s not possible, only then do I recycle it.

Because glass can be reused, many companies have glass take back programs so they can reuse the item multiple times before ultimately, hopefully sending it for recycling instead of it ending up in landfill. I want to urge all companies that sell products in glass packaging to implement take back programs for their glass packaging. After all, consumers should not be solely responsible for what happens to packaging after purchase.

Recycling glass

Most glass is infinitely recyclable so it can be recycled over and over without losing quality.

Once you have added your glass to a recycling bin or collection point, it will most likely be transported to a sorting facility before being transported to a recycling centre, where it will be turned into cullet, (crushed glass) The cullet is then transported to glass manufacturers.

There was a study done in 2019, that found using at least 30% cullet together with raw virgin materials to make new glass products, results in a significant reduction in CO2 emissions, waste, energy and costs.

Once the glass is transformed into a new glass product, the cycle mentioned above can continue indefinitely.

My thoughts

Even with all the things I have learned about the negative environmental impact throughout the lifecycle of glass, I still believe that the glass recycling process has the potential to become a leading example of a closed loop sustainable practice as part of a circular economy.

There is though, still a lot that needs to be done to make the glass recycling and glass manufacturing process using cullet, more sustainable with the goal of reusing and restoring natural resources.

I hope you have found this blog post interesting and useful. I’ll be adding more similar posts soon! If you would like some info about my green vegan lifestyle and the vegan products I use, please take some time and browse through my blog. I have a section where I post recipes I’ve created, or you could browse through the food and drinks section. Alternatively, you could head on over to the body & beauty OR home & garden section to see what products I personally use on myself and at home.

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