How much water is used to make plastic bottles?
PET (Polyethylene terephthalate) bottles are one of the most widely used forms of packaging in the world today.
PET bottles are lightweight, durable, and have a wide range of applications. They’re used for packaging bottled water, carbonated drinks, salad dressings, cooking oil, peanut butter, liquid hand soap, mouthwash and pharmaceuticals. PET is even used in the manufacture of tennis balls!
Virtually all single-serving and larger bottles of carbonated soft drinks and water sold are made from PET.
The production of PET bottles requires a significant amount of water. It’s not just the impact of the water that’s contained in the bottles, but also the amount that’s used in their production. In this blog post, we’ll explore how much water is used in the manufacture of PET bottles.
The manufacture of PET bottles involves several stages, including the production of PET resin, the formation of preforms, and the blow-moulding of bottles. Each stage requires water, and the amount of water used varies depending on the process.
PET Resin Production
The first stage in the manufacture of PET bottles is the production of PET resin. This process involves the polymerization of ethylene glycol and terephthalic acid to produce PET resin.
This process requires water to cool the reactor and maintain the desired temperature during the process. According to a study by the Pacific Institute, it takes approximately 1.6 litres of water to produce 1 kilogram of PET resin.
The next stage in the manufacture of PET bottles is the production of preforms.
Preforms are small, tubular plastic containers that are used as the starting point for the blow-moulding process. Once again, water is required for cooling and lubrication during this stage.
According to the same study by the Pacific Institute, it takes approximately 0.24 litres of water to produce one preform.
The final stage in the manufacture of PET bottles is the blow moulding process.
This is where the preforms are heated and then moulded into the final bottle shape that we’re so familiar with. Once again, water is needed to cool the moulds and the bottles after they’re formed.
The Pacific Institute recorded that it takes approximately half a litre of water to produce one PET bottle during this phase.
Taking all three processes into account, it takes just over 2.3 litres of water to produce one PET bottle.
This figure may vary depending on the production process used, but it provides a general idea of how much water is required to produce each bottle.
Studies have shown that almost one million plastic bottles are purchased each minute across the globe – that’s around 1.4 billion bottles each day. Multiply that by the 2.3 litres that it takes to produce a PET bottle and that adds up to over 3.3 billion litres of water that’s needed to manufacture the bottles consumed in one day.
And that doesn’t include the water that’s contained in the bottles.
The production of PET bottles is not only water-intensive but also has other environmental impacts:
· The PET resin in the first stage of production is produced from petroleum and natural gas
· Each bottle takes about 4 million joules of energy to create
· Every ton of PET that’s produced creates three tons of CO2
· Disposal of PET bottles contributes massively to environmental pollution
It’s therefore essential to find a more sustainable production process, promote recycling of PET bottles and find ways to reduce our reliance on single-use plastic.
In summary, the manufacture of PET bottles requires a significant amount of water – much more than just the water contained in the bottles.
The production processes of PET resin, preforms and blow-moulding each require water. The total water usage for one PET bottle is approximately 2.34 litres. It’s therefore crucial to consider the environmental impact of PET bottle production and promote sustainable practices to reduce water usage and environmental pollution.