C14 - The Earth's Resources Flashcards
D. Finite?
Will eventually run out
D. Renewable?
Can be replaced
How is water purified?
- passing through filter beds to remove solids
- adding chlorine or ozone
- by passing UV rays through to reduce microbes
Cons of water distillation?
expensive
requires large amounts of energy
How is salt water purified? (reverse osmosis)
uses membranes to separate dissolved salts from salty water
Cons of reverse osmosis?
expensive as uses energy to make high pressure conditions needed
pipes are corroded by salt
Series of steps involved in sewage treatment?
1) Screening - removes large solids from water
2) Primary treatment - solids removed by letting them settle
3) Secondary treatment - useful bacteria break down remaining organic matter
4) Final treatment - useful bacteria settle and are removed as sediment - can be filtered through a sand bed/ UV/ chlorine (chlorine may cause damage to ecosystems)
How is sludge made safe?
- separated
- broken down by anaerobic digestion
- dried
Uses of sludge?
fertiliser
source of renewable energy
D. Life Cycle Assessment?
Carried out to assess the environmental impact of products, processes or services at different stages in their life cycle
Summary of stages of LCA?
Raw material extraction – Manufacture – use/reuse/maintenance – recycle/waste management
How is most copper extracted?
smelting copper-rich ores
How can copper be extracted?
electrolysis
- displacement using scrap iron
D. Bioleaching?
Using bacteria to to help extract copper
D. Phytomining?
Using plants to help extract copper
