C10 - Using resources Flashcards
What are the 4 main stages of a product life cycle?
- Extracting and processing the raw materials
- Manufacturing and packaging your product
- Using your product
- Disposing of it
What is the purpose of a life cycle assessment?
To assess the environmental impacts of products
What is potable water?
Water that’s safe to drink
What is pure water?
Water that only contains water molecules
Is potable water pure?
No, it often contains other dissolved substances which makes it impure
What is the 3 criteria for potable water?
- Levels of dissolved substances need to be fairly low
- pH between 6.5-8.5
- No micro-organisms
What are the 3 steps to treat fresh water?
- Filter through a wire mesh (filter our any big objects)
- Filter through sand and gravel (filters out other smaller bits)
- Sterilise it (kill any harmful microbes)
What are the 3 ways to sterilise water?
- Bubbling chlorine gas through it
- Expose it to ozone
- Expose to ultraviolet light
What is desalination?
Extracting potable water from sea water
What is an aquifer?
Permeable rock underground that traps water
What are the 2 main techniques used in desalination?
- Simple distillation
- Reverse osmosis
What are the 3 main steps to treat sewage water?
- Screening (remove anything large)
- Let the sewage sit in a settlement tank (allows it to undergo sedimentation - heavier bits sink to the bottom and form sludge and are left with the effluent which are both sent to different tanks)
- Pumping air into the effluent tank to supply the bacteria with oxygen (the microbes in the tank can break down the organic matter by aerobic digestion)
What is the main drawback of desalination?
It requires a lot of energy, so is very expensive
