E8+Waste

**__E8 Waste__**
__E8.1__ __Methods of waste disposal__ Example of open dumping in Alaska:-
 * ~ Landfill || (+) can deal with large volumes easily and can be used to build land ||
 * ~  || (-) takes time and methane is being released into the atmosphere ||
 * ~ Open dumping || (+) convenient and cheap ||
 * ~  || (-) causes air and water pollution and takes up space ||
 * ~ Incineration || (+) more efficient as the residue is stable, odourless and can be reused. ||
 * ~  || (-) requires large amounts of energy so it is expensive to carry out. It could also produce toxins if not burnt properly. ||
 * ~ Ocean dumping || (+) convenient, and this method is cheap ||
 * ~  || (-) can be dangerous for marine animals and the sea may be polluted ||
 * ~ Recycling || (+) encourages sustainability and causes less damage to the environment ||
 * ~  || (-) produces air pollution, takes a lot of time and is difficult to separate the different materials. This method usually needs government's encouragement. ||

__E8.2__ __Recycling__
 * ~ Metals || Metals such as aluminium and steel can be collected and melted. The mixture will then be remoulded and reused. ||
 * ~ Paper || The used paper is mixed with chemicals and water, which is then spun, washed, dried and bleached. ||
 * ~ Glass || Glasses of different colours are sorted then washed, crushed and remoulded into shape. ||
 * ~ Plastics || Plastics are sorted into different types, which are then degraded into monomers through methods such as gasification, thermal cracking, hydrogenation. The monomers are then repolymerised and reused. ||


 * Benefits of recycling**:
 * Saves space in landfills
 * Saves raw materials
 * Saves energy that will be needed for the production of new raw materials



__E8.3__ __Different types of radioactive waste__ Low level radioactive waste:
 * Includes paper, gloves or clothing exposed to radioactive materials
 * Half life: short
 * Activity: low
 * Usually from equipments used for cancer treatments in hospitals and any materials that has been in contact with the radioactive material

Storage and disposal of low level radioactive waste:
 * 1) Stored in cooling ponds for a period of time until the level of activity has fallen by giving off heat. Alternatively, the waste can also be stored in concrete and steel containers.
 * 2) Passed through ion exchange resins to filter out the ions responsible for radioactivity, e.g. caesium and strontium.
 * 3) The water is then released into the sea and diluted.

High level radioactive waste:
 * Generated in power stations, nuclear power plants, fuel rods, the military and the reprocessing of spent fuel rods
 * Half life: long
 * Activity: high

Storage and disposal of high level radioactive waste:
 * 1) High level radioactive waste has long half-lives so sometimes they are being reused.
 * 2) If not, it will produce a high level liquid mixture of radioactive waste.
 * 3) Firstly the liquid needs to be dried in a furnace and mixed with sand (which makes glass) in a melting pot.
 * 4) The mixture cools and solidifies in a steel container.
 * 5) These containers will remain radioactive for thousands of years, and stored in concrete vaults.
 * 6) However problems may arise with the leaking of radioactivity into the water supply and the availability of storage space.