C14 Flashcards
What are finite resources?
Resources that are being used up at a faster rate than they can be replaced.
What are renewable resources?
Those that can be replaced at the same rate at which they are used up.
What is potable water?
Water that is safe to drink.
What are the 6 stages of making water potable?
1.The water passes through a cage-like metal screen that catches large objects such as sticks and leaves
2.Passes through a coarse filter
3.Passes through a sedimentation tank, where sand and soil falls to the bottom
4.The water then passes through a fine sand filter, so no particles of dust remain
5.The water contains bacteria so small amounts of chlorine are added to kill any harmful bacteria
6.The pH is checked and maintained then it is distributed
What are the 4 stages of sewage treatment?
1.Screening-larger solids and grit reduced by running water through a metal grid
2.Primary treatment-solid material allowed to settle in a circular tank, with water above being effluent
3.In the next tank, useful bacteria feed on any remaining organic matter and break it down by aerobic respiration
4.Useful bacteria allowed to settle out of the bottom of the tank, sediment recycled back into stage 3 or added to sludge at stage 1, waiting for treatment.
What happens with the sludge in stage 2?
It is treated further where it is anaerobically digested by microorganisms. Higher temp for breakdown of organic material and produces a biogas which can be burned for energy. Then dried out for ‘crusty cake’ which is burned for energy.
How can salty water be purified?
It is often called desalination where they use reverse osmosis using membranes to separate the water and the salts dissolved in it.
What are the two main methods of extracting copper from the ore?
In one method, sulfuric acid is used to produce copper sulfate solution before extracting the copper metal and the other method is called smelting where it is heated to a high temperature to produce improper copper.
What is phytomining?
Where plants that absorb copper ions are grown on soil containing low grade copper ore. These plants are burnt and copper is extracted. It is dissolved from the ash by adding sulfuric acid and then displaced by using electrolysis for a pure copper metal.
What is biobleaching?
Bacteria feeds on low-grade metal ores, so a solution of copper ions can be obtained from waste copper ore. Scrap iron and electrolysis is used to extract the copper from the solution.
What does an LCA assess?
Getting and processing raw materials, making the product, using reusing and maintaining the product and disposing of the product at the end of its useful life.
How is an LCA carried out?
Listing all the energy and material inputs and outputs into the environment. Evaluating the potential environmental impacts from these inputs and outputs. Interpreting the results to help make decisions about using one material, process, product or service over another.
What are the stages of an LCA?
Raw material extraction, manufacture, use/reuse/maintenance and recycle/waste management.
What are the aims of reduce, reuse and recycle?
Reduce or use of limited resources, use of energy and what waste we produce.
Why do we recycle aluminium?
As it is heavily used and needs to be made through electrolysis which needs large amounts of energy.
Why do we recycle iron and steel?
To avoid the negative impacts of blast furnaces on the environment.
