Topic 10 Flashcards
How is potable water produced in the UK?
Choose appropriate source of fresh water
Pass water through filter beds to remove solids
Sterilise to kill microbes
What are the sterilising agents for potable water?
Chlorine- toxic so amount added has to be carefully monitored
Ultraviolet light- kill microbes and avoids using chemicals. More expensive
How is desalination carried out?
Can be done distillation or processes that use membranes such as reverse osmosis. Require lots of energy
What is reverse osmosis?
Sea water passed through membrane- only allows water molecules through.
Needs high pressure to push water through membrane.
High pressure needs lots of energy.
How is wastewater produced?
Urban lifestyles and industrial processes produce lots of waste water
Sewage and agriculture waste water require removal of organic matter
What are the processed involved in sewage treatment?
- screening and grit removal
- sedimentation to produce sewage sludge and effluent
- anaerobic digestion of sewage sludge
- aerobic biological treatment of effluent
What is phytomining?
Uses plants to absorb metal compounds from soil. Plants are harvested and burned to produce ash that contains metal compounds
What is bioleaching?
Uses bacteria to produce leachate solutions that contain metal compounds
What are the main advantages and disadvantages of phytomining and bioleaching?
Need less energy than traditional methods and can work on low concentration ores
Are slow to carry out
Describe the stages of LCAs
They are carried out to assess environmental impact of products in each stage;
- extracting and processing raw materials
- manufacturing and packaging
- use and operation during lifetime
- disposal at end of useful life
Why do we reduce the resources?
Reduces the use of limited resources, energy consumption, waste and environmental impacts
What are the advantages and disadvantages of recycling?
A: less pollution/ metal ore reserves last longer/ conserved energy for extraction saved less mining
D: collection problems/ transport problems/ cost of transport
