The Life Of A Plastic Milk Bottle - Biffa
Milk bottle recycling

Life of a plastic milk bottle

5 Jun 2019
6 mins

There is an extensive list of different types of milk – skimmed, full fat, organic, soy, chocolate, oat and many others, but the most used milk comes from a plastic bottle. When you purchase a bottle of milk, do you ever think what happens to the bottle once it’s empty or what happened to it before it arrived in the supermarket’s fridge? Would you be surprised if these two questions have exactly the same answer? Plastic milk bottles can be recycled through a closed loop process – this means that the milk bottle you put in your recycling bin can be part of a new bottle! 


Making milk bottles

Plastic bottles are made out of HDPE – high density polyethylene – which is identified as the number “2” in the recycling triangle.


Why is HDPE used instead of other materials?

As HDPE is strong and lightweight, it helps reducing the weight of heavy volumes of liquid. If you were to carry six pints of milk in a glass jug, it would be quite heavy and if dropped, it would smash. While plastic milk bottles can also break when dropped from a significant height, they would not shatter. 

HPDE is a food-grade plastic, so it’s safe for storing perishable goods for a short amount of time. It can also be shaped to make a handle, making for easy manoeuvring from the fridge to the counter, especially useful for the elderly or those with disabilities. 

How is the plastic turned into milk bottles?

Firstly, recycled pellets, also known as rHDPE, are blended with virgin material which is then directly moulded into the shape of a milk bottle – the process looks like blowing up a balloon with warm air! As the walls of the bottle mould are cold, once the plastic hits them, it instantly cools and sets.

Filling the milk bottles

Did you know? A cow can produce up to 30 litres of milk a day, that’s sixty 1-pint milk bottles.

No matter who made the bottles or filled them with milk, up until recently all milk bottles used to look the same, having a natural colour. Because of colouring, white milk bottles cannot be recycled into new bottles, however, they can still be recycled into other products. It’s not until the labels are added to the bottles at the dairies that they recognisable as different brands. To ease the recycling process, the labels have been designed to fall off easily.
Milk bottle recycling

Purchasing a bottle of milk

Did you know? Compared to other milk types, skimmed milk is the highest retail expenditure in Great Britain.

The most familiar step of the milk bottle’s journey is the actual purchasing of the milk, so we won’t explain how this works! 

Disposing of milk bottles

The milk bottle’s journey with the consumer will end once all the milk has been consumed, then it is time to move to the next step – disposal. An important step in recycling is cleaning out the milk bottle – cleaning it will not only reduce the odours in your bin (who likes the smell of sour milk?), but it will also remove the contamination possibility of dry materials such as paper and cardboard in your recycling bin. 
Should you remove lids and labels too?
No need to remove the labels and lids from milk bottles, labels are specifically designed to be easily removed during the recycling process and the caps will be recycled into other new products.

Recycling milk bottles

The recycling process is the final step in the life of a plastic milk bottle. It starts when waste service vehicles like the Biffa’s Wasteater’s collect recycling, either from household kerbside or from businesses and transport the waste to a transfer station, a central location where all waste vehicles drop off their waste collections.

The materials from transfer stations are then weighed and sent to processing facilties – along with other recyclables, plastic milk bottles are sent to a MRF – materials recycling facility. 
Materials go through mechanical and manual sorting to remove any non-recyclable materials that have accidentally made their way to the MRF before being separated by material type.
Closed loop plastic
After that milk bottles are flattened and baled to be transported to Biffa Polymers that can accept around 24,000 tonnes of materials every year! Once they arrive at Polymers, the bottles will be industrially cleaned, shredded and then turned into plastic pellets. Watch the video below plastic is recycled at our award-winning facility.
Biffa Polymers produces approximately 18,000 tonnes of food grade material every year. The produced pellets are sold to milk bottle manufacturers. Along with virgin plastic, the recycled plastic pellets will be used to create a brand new milk bottle and like this the whole process starts all over again!

Did you know? Even though you cannot tell all major diaries companies use recycled materials in their bottles, milk bottles are now up to 40% recycled content in the UK. 
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Author: Biffa

This article was written by one of Biffa's own experts and content writers.