Environmental chemistry

1. Environmental chemistry Waste

2. waste • Outline and compare the various methods for waste disposal. • Describe the recycling of metal, glass, plastic and paper products, and outline its benefits. • Describe the characteristics and sources of different types of radioactive waste. • Compare the storage and disposal methods for different types of radioactive waste.

3. waste disposal

4. Recycling • Reduces energy cost. • Reduces CO2 emissions. • Reduction in volume of waste. • Saves Earth’s metal ores reserves, trees, crude oil. • Creates jobs in collecting, sorting and recycling

5. recycling glass • Different glass types must be separated. • Glass is then crushed. • Other substances are removed such as metals, labels. • Glass is melted and remoulded. • Glass can be recycled many times.

6. metals • Saves Earth’s metal reserves. • Reduces energy costs in extraction (mining, transport and purification). • Collection, sorting and recycling provides jobs. • Many recycled metals are used in alloys.

7. recycling plastics • Difficult to recycle as there are so many different plastics each needed a different type of recycling. • Main stages: • After collection, manually sorting of different plastics • Washing of plastic • Most plastics melted and then moulded into new shape; • Other first shredded into flakes, then molten and processed into granules or pellets • Future = biodegradable plastics

8. recycling paper • Water is added to waste paper to make ‘pulp’ and separate fibres • Pulp is centrifuged to remove denser components such as clay, dirt, metals, .. • Air is pumped through it to remove ink • To make white paper it needs to be bleached. • Pulp is compressed to make new paper

9. radioactive waste - low level

10. radioactive waste – high level