- Plastics are more difficult to recycle than other materials. The reason is that there are different types of plastics and that plastic is not a natural material. Most plastics are, therefore, non-biodegradable. When a plastic container reaches a landfill it will not corrode or rust in the course of time.
- Many plastic products are marked to help consumers tell which plastics can be recycled. The recycling process for plastic normally involves cleaning it, shredding it into flakes, then melting the flakes into pellets which can be melted into a final form like plastic milk crates, car carpets etc. Burning plastics emit poisonous or irritating fumes which add to air pollution. Because the recycling of plastics is so problematic only about 5% to 10% of plastics are recycled. Researchers are working to develop biodegradable plastics that will disintegrate due to bacterial action or exposure to sunlight.
3.1 Explain the term “non-biodegradable”.
3.2 List products that are packed in plastic containers.
3.3 Why is plastic such a popular material for packaging?
3.4 Write a paragraph on why plastic waste is such a major problem.
Activity 4
To demonstrate an understanding of how materials (glass) can be recycled
- Glass is a strong, transparent material which is used for windows, bottles, glasses etc. It has some unusual properties – it melts easily, is chemically inactive and is cheap because its main ingredient is sand.
- In many towns and cities there are bottle banks where one can throw away ones glass waste. Some places even have two separate containers: one for coloured glass and the other for white glass. The glass is taken to a recycling plant where it is cleaned and then crushed. The waste glass is called “cullet” and melts at a lower temperature than the raw materials of glass. This saves energy and raw material. Many companies give a deposit on their empty bottles which is even better than what is paid by a recycling plant.
4.1 Name two advantages of glass.
4.2 Name the disadvantages of glass that you can think of.
4.3 What makes the glass used in a motor-car different?
4.4 What is glass fibre?
Activity 5
To demonstrate an understanding of how materials (paper) can be recycled
- Every day people throw away tons of paper. There are ways of collecting paper and using it to make new paper. To recycle waste paper so that it is as white as writing paper, any printing ink on the waste has to be removed. The waste is collected in bales and shredded into small pieces. It is then fed into a pulper. Here hot water and chemicals help to separate the paper fibres and remove the ink. Caustic soda is usually used for this purpose. Poorer quality paper like that used for newspapers is mixed with water to form pulp which can be fed in to a paper-making machine.
- Paper is made from wood. About 35 million trees could be saved each year if 75% of waste paper and cardboard were recycled into pulp and used to make new paper. In some tropical countries large areas of hardwood forest have been cleared of mature trees. This is called “deforestation”. This can be very harmful to the environment because the soil can now be washed away by the tropical rains.
- Trees provide oxygen which we all need for survival. They also provide shelter and homes for many animals. Luckily re-forestation is taking place in many parts of the world. Trees are one of the natural resources that can be replaced by planting new trees.
