C19 Using Earth's resources Flashcards
Pure water
Just H2O molecules
Nothing else
Potable water
Water molecules with low levels of salts
Safe levels of harmful microbes
Salty water
Water molecules
Dangerously high levels of salt
Can have high levels of harmful microbes
Fresh water
Water molecules
Low levels of salt
High levels of harmful microbes
Where does fresh water come from?
Rivers
Lakes
Underground
2 ways salty water can be made in to potable water
Distillation
Reverse osmosis
How does reverse osmosis work?
Membranes separate salts that are dissolved in the water
Water MUST be pressurised as the salty water corrodes the water pumps
Why must the water be pressurised during reverse osmosis?
Otherwise the salty water will corrode the pumps
Disadvantage of reverse osmosis
Expensive due to the pressurisation
How can fresh water be made in to potable water?
Choose an appropriate source of fresh water
Pass water through filters to remove large objects
Sterilise water to kill any microbes using chlorine, UV light and ozone
3 ways to sterilise fresh water
UV
Chlorine
Ozone
How can desalination be carried out?
Distillation
Reverse osmosis
What can waste water contain?
Harmful microbes
Organic waste
Harmful chemicals
What are the three types of waste water?
Sewage
Agricultural waste
Industrial waste
What is the first step in processing waste water?
Screening and grit removal
What is the second step in processing waste water?
Sedimentation
What is sedimentation?
Separating water in to sludge and effluent
How is sludge treated?
1. Anaerobic respiration
- Bacteria are added to digest the organic matter
- Break down the material with limited oxygen
2. Biogas
The anaerobic respiration produces biogas
3. Remaining sludge used as fuel
- It is dried out then burnt for fuel
How is effluent treated?
Aerobic respiration
- Bacteria are added to effluent
-These bacteria feed on organic matter and microbes
Bacteria is then removed
Discharged back to rivers
What is biogas?
A mixture of methane, CO2 and hydrogen sulfide
Used as fuel
What is phytomining?
Using plants to extract copper
What is bioleaching?
Using bacteria to extract copper
How does phytomining work?
Grow plants near the metal ore
Harvest and burn the plants
Ashes contain the metal compound
Process the ash by electrolysis or displacement with a scrap metal
How does bioleaching work?
Grow bacteria near the metal ore
Bacteria produce leachate solutions that contain metal compound
Process the leachate by electrolysis or displacement with a scrap metal
Advantages of Phytomining and bioleaching
Avoid digging and moving large amounts of rock associated with traditional mining methods
What type of rock is used for phytomining and bioleaching?
LOW GRADE ORES
(Ores with only little copper in them)
What is a life cycle assesment?
LCA
A way of assessing the energy costs and environmental impact of a product over its lifetime
What are the four stages of LCA?
Extracting and processing raw materials
Manufacturing and packaging
Use and operation during its lifetime
Disposal
How can products be disposed?
Landfill
Incineration
Reused
Recycled
