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Which is Better For The Environment? Glass or Recycled Plastic (rPET)?

When you search for zero waste products, you’re bound to notice tons and tons of pictures of glass jars and bottles. From the drinks we consume to the jars lining our pantries, glass is pretty popular in the zero waste community and spruiked as an eco friendly alternative, but is it really?


Well, perhaps the answer isn’t as clear cut as you may think. This is a long post but worth it.

Australia Exported 126,300 Tons of Plastic Garbage in 2019–20. 61.3% of the plastic was recycled in Australia, while 200,300 tonnes, or 38.7%, was exported outside. According to the latest available data, the total plastic waste generated in Australia was approximately 3.5 million tonnes in 2019-20. That said, there’s so much more to think about in terms of what goes into manufacturing and recycling both glass and plastic, not to mention all the environmental impacts shipping, transportation can cause.

Glass

Glass is a useful material for everything from preserving food to carrying signals that power the internet. So essential is glass to human development that the United Nations named 2022 the International Year of Glass to celebrate its contribution to cultural and scientific development.

Glass can often be referred to as a material which can infinitely be recycled without impacting its quality, purity or durability and recycled glass can be crushed into glass 'cullets', which can be melted down and used to produce more glass and glass used for packaging has a high recycling rate compared to other packaging materials. Sand Mining Unlike plastics, which break down into dreaded microplastics that can leach into our soils and water, glass is non-toxic as it's made mostly of silica, sand. Silica, also known as silica dioxide, makes up 59% of the Earth's crust. Since it is a natural compound, there is no concern about leaching or environmental degradation.


Because sand is natural we often think it's best and glass is often touted as a more sustainable alternative to plastic.


Map of Australian sand mines.


However, glass bottles have a higher environmental footprint than plastic and other bottled container materials including drink cartons and aluminum cans. The mining of silica sand can cause significant environmental damage, ranging from severe land deterioration to the loss of biodiversity and water pollution. Extracting sand for glass production may also have contributed to the current global sand shortage. Sand is the second most-used resource in the world after water – companies use over 50 billion tonnes of "aggregate", the industry term for sand and gravel, each year.

Its uses range from land regeneration to microchips. According to the UN, sand is now used faster than it can be replenished and illegal sand mining is rampant, often in designated nature reserves, national parks and sanctuaries.


Sand Mine WA.

Glass also requires higher temperatures than plastic and aluminum recycling to melt and form, says Alice Brock, a PhD researcher at University of Southampton in the UK. Raw materials for making virgin or recycled glass also releases a lot greenhouse gases during the melting process, adding to its environmental footprint. According to the International Energy Agency, the container and flat-glass industries emit over 60 megatonnes of CO2 per year. It may seem surprising, but Brock's study found that recycling plastic bottles is far less environmentally damaging than glass bottles. Although plastic cannot be endlessly recycled yet, the manufacturing process is far less energy-intensive, as there is a lower melting point for plastics compared with glass and little water usage. Raw materials for glass are melted together in a furnace at 1500C. The molten glass is then removed from the furnace, shaped and moulded. Glass production facilities often add only a small portion of recycled glass cullets into the virgin glass material mix. Generally, a 10% increase in glass cullet into the container glass melting mixture can decrease energy consumption by 2-3%. This is because it requires a lower melting point to melt glass cullet compared to the virgin materials used to produce glass. In turn, this slightly reduces the CO2 emissions produced during manufacturing.

A key problem with glass recycling is that it does not eradicate the remelting process, which is the most energy intensive part of glass production. It accounts for 75% of the energy consumption during production. Even though glass containers can be reused an average of 12-20 times, glass is often treated as single-use.and once in landfills can take up to one million years to break down.


Single-stream recycling often complicates the sorting process, since glass must be separated from other recyclables we pop in our bins and sorted by colour before it can be remelted. Often, it is too time-consuming, and therefore expensive, to separate mixed coloured glass at a recycling facility.

The colour of glass affects how pure the stream needs to be. While green glass can use 95% of recycled glass; white or colourless glass, also known as "flint glass", has higher quality specifications and only permits up to 60% recycled glass because any contamination affects the quality.


There is no doubt that glass still plays an important role in many industries. Its durability and non-toxic properties make it ideal for foods and materials which require preserving. However, the assumption that glass is sustainable merely because it is infinitely recyclable is misconstrued. Considering its entire lifecycle, glass production may be equally as detrimental to the environment as plastic if not worse when factoring in sand mining.

Recycling If glass manufacturers used 50% recycled content to make 'new' glass it would remove 2.2 million metric tons of CO2 from the environment. That’s the equivalent of removing CO2 emissions of nearly 400,000 cars every year.

While glass is completely recyclable, unfortunately much of the contaminated glass or glass stockpiles are crushed and used as a landfill cover which happens a lot here in Australia as well as overseas. Landfill covers are used to control the offensive smells landfills give off, deter pests, prevent waste fires, discourage scavenging, and limit rainwater runoff.


Landfill Cover - bottles are crushed down into smaller pieces by the compactor tractors over time.

Landfill Cover

PET into rPET

Virgin plastic production begins by treating components of crude oil or natural gas in a “cracking process” where they are converted into hydrocarbon monomers, such as ethylene and propylene. Even more processing leads to various other monomers, such as styrene, ethylene glycol, terephthalic acid, vinyl chloride and several others. These monomers are then chemically bonded into chains called polymers.

The different combinations of monomers yield various different kinds of plastics, all with a wide range of characteristics and properties. There are seven major plastics that are used widely such as Polyethylene Terephthalate (PETE), High Density Polyethylene (HDPE), Polyvinyl Chloride (PVC), Low Density Polyethylene (LDPE), Polypropylene (PP), Polystyrene (PS) and other plastics (ex: nylon). Pollution & Energy All these different plastics serve different functions, though some are easier to recycle than others. As you can imagine, creating all those virgin plastics takes a lot of energy and resources. In fact, the emissions from virgin plastic in 2015 were equivalent to nearly 1.8 billion metric tons of CO2.

It doesn’t help the factories used to create virgin plastic also run on fossil fuels and produce emissions as well. To be fair though, factories that produce glass also create emissions and run on fossil fuels for the most part. rPET stands for recycled polyethylene terephthalate, or recycled PET. PET (polyethylene terephthalate) itself is a polymer used to widely manufacture affordable, durable and recyclable containers and packaging as well as a form of polyester. Recycling PET into rPET

By recycling post consumer waste into a valuable resource, rPET excels in the sustainability compartment compared to virgin PET bottles. The use of rPET plastic is on the rise as a result of its very low carbon footprint (saving raw materials by requiring less energy), recyclability (reducing waste), and strong environmental benefits. As more and more brands continue to adopt the use of rPET, we are setting a standard where rPET is routinely used instead of regular PET bottles. Lil'Bit uses 100% Post consumer waste rPET saving existing PET from landfill.

When PET packaging is recycled/discarded by us, the consumer, it becomes waste. That waste then makes it way to a material recovery facility (MRF) where it is sorted from other materials, baled, and sent to specific PET recycling facilities. At these new facilities, each bottle is washed and contaminants are removed (water is continuously recycled unlike glass recycling). The bottles then get sorted according to color and are ground into flakes or made into pellets. These flakes and pellets are then sold as raw material that can be used for a range of products (clothing, carpets, insulation, etc) or made back into rPET bottles that can be recycled again and again, just like glass. Energy Consumption In the closed loop, bottle to bottle system described above, 100% recycled polymers directly replace virgin polymers to create several major advantages in the realm of energy, greenhouse gas emissions and cost. Unlike glass where only a small percentage of recycled materials still need to be added to a virgin mix. The process of converting rPET requires substantially less energy than glass, aluminum, or other materials. Although PET’s is derived from crude oil and natural gas, approximately 40% of that energy is trapped within the PET polymer for recapture and reuse every time PET is recycled. This means rPET leads to a greater conservation of raw materials and a reduction in greenhouse gas emissions by 65%

Since PET is lightweight and more compact, it allows for more product to be delivered with less packaging, less weight and less fuel for transport, and with less trucks on the road.

It takes 12.2kg of glass versus 90g of plastic to deliver 30 L of product.

rPEt plastic means a reduction in breakage and damaged goods compared to glass packaging.

The reality is that 100% of all PET products can be made from rPET. In addition to all the advantages of rPET plastic, consumers are actively looking for companies that are committed to sustainability, recycling and the overall green agenda.

Last but not least, the closed loop cycle of rPET relies on the consumer to recycle. It only works if this necessary step takes place, so please, always recycle you rPET bottles!

Phew! I told you this was a long blog post!

Both recycled glass and rPet have pros and cons but I bet you thought it was more clear cut than this didn't you? I did. I had no idea glass took so many natural resources to make and recycle, let alone the impact on the environment. Like many of you I thought choosing glass was a no brainer until I really looked into it. The choice is yours but we shouldn't be so quick to demonize rPET either. If we don't use existing plastics in the form of rPET they will end up in landfill = waste. So being waste free is not being plastic free, it's being VIRGIN plastic free.



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