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How your Litter is Recycled
Here we look at the different ways that items are recycled.
Paper:
- Paper is collected together and sent to a paper bank
- From here it is taken to a large recycling centre where the different types of paper are separated out from each other. This needs to be done because different types of paper need to be recycled in different ways
- Each type of paper is then added to a machine called a pulper. This contains a mixture of water and chemicals
- The pulper chops the paper into really small pieces to makes it easier to recycle
- The mixture of paper, water and chemicals is heated which breaks the small pieces into small strands. These are called fibres.
- The mixture eventually becomes a mush. This is called a pulp
- This pulp is forced through a number of screens to remove the contamination. Contamination is the name given to the ink and writing which was on the paper before it was chopped into small pieces. This process is called de-inking.
The De-Linking Process
- The pulp is washed to remove some of the ink. This involves chemicals being added to the mixture to lift the ink off the surface of the paper
- After this a process called floatation is used. This is when air and surfactants are pumped into the water. A surfactant is a chemical which helps to break the surface tension of the water down so it can mix with the paper pulp
- The ink on the paper sticks to the air bubbles as they are pumped through the mixture. These air bubbles then rise to the surface of the pulp mixture and form a froth, which can then be removed from the surface of the mixture
- This cycle is repeated a number times to remove as much of the ink as possible from the mixture
- The pulp then needs to be refined. To do this the pulp is beaten to make the fibres swell. Doing this makes it easier to remould the paper into sheets by making it more flexible. If it is a batch of white paper it is then bleached to remove any remaining coloured inks
- After this process the pulp is removed from the mixture and added to water to make it 99.5% water. This liquid is then sprayed onto a wire screen which is moving very quickly. As the pulp spreads across this sheet the water runs off leaving a watery sheet
- The sheet is fed through a series of rollers which squeeze out more of the water. The sheet is then fed through a set of heated rollers which dry it out into large sheets of paper
- This paper is then put onto a large rollers and made into a roll ready for cutting and sizing.
Cans
- All the cans are collected together at large regional centres
- The can are then compacted into bales before being transported to the recycling centre
- After being unloaded at the recycling centre the can are crushed, and shredded
- Next they have the coating on the outside removed by burning them at high temperatures to remove the colours
- They shreds of aluminium are then loaded into a furnace where they are melted together with new bits of aluminium
- The liquid metal is then poured into large ingots, or large metal moulds
- Before the metal cools it is fed through a series of rolling mills which squash it down from a thickness of more than 20 inches to sheets about 10/1000 of an inch thick
- These large sheets are then coiled and rolled so they can be transported easily
- These sheets are sent to can makers who reform the aluminium into cans and make the lids
- Once complete the cans are delivered to the drinks makers where they are re-coated, filled and sealed
- It can take as little as 60 days for a can to be recycled and be back on the shelves in a shop
- Once they have been used again they can be sent for recycling again.
Food and Packaging
Although it is recyclable food waste is not recyclable into new food. It can be recycled and used in other ways though. It is a valuable energy source. We eat food for energy and recycling waste food to make use of the energy it contains allows us to create electricity with it.
- The food and packaging waste are collected in special bins around the school
- The bins are emptied into a large container which is collected and taken to a processing centre
- Here the food and packaging are loaded into a processing unit
- This slowly churns the waste against while being gently heated from the bottom of the processing equipment
- As this happens the water in the food becomes hot and evaporates away. After 18-20 hours of going through this process almost all of the moisture has been evaporated away and what is left is a powder which looks and feel like breadcrumbs
- The water that is removed as steam is converted back to water and drained away
- The dry powder, also called a biomass fuel, is then fed through to a unit which converts it to a gas
- It does this by sprinkling the powder through a oxygen free space which is heated to around 850°C. As the powder drops through this space it cannot stay in its natural form and vaporises it into a gas
- From here the gas is cooled and cleaned before it is fed into a gas engine. This is like a car engine which runs on gas
- These engines generate electricity which is then fed back into the electricity grid before being sent out to houses.
How can we work towards a greener world?
There are many ways which we can work together to make the world greener.
Recycling paper, cans and food is only the start.
There are many things you can do around the home which will help save the planet. Here is a list of some things that you can do around your home:
Switch off plugs on items not being used
Turn off lights when you leave the room
To be completed.