C19 Using Earth's resources

Question 1

Pure water

Answer 1

Just H2O molecules
Nothing else

Question 2

Potable water

Answer 2

Water molecules with low levels of salts

Safe levels of harmful microbes

Question 3

Salty water

Answer 3

Water molecules
Dangerously high levels of salt

Can have high levels of harmful microbes

Question 4

Fresh water

Answer 4

Water molecules
Low levels of salt

High levels of harmful microbes

Question 5

Where does fresh water come from?

Answer 5

Rivers
Lakes
Underground

Question 6

2 ways salty water can be made in to potable water

Answer 6

Distillation
Reverse osmosis

Question 7

How does reverse osmosis work?

Answer 7

Membranes separate salts that are dissolved in the water

Water MUST be pressurised as the salty water corrodes the water pumps

Question 8

Why must the water be pressurised during reverse osmosis?

Answer 8

Otherwise the salty water will corrode the pumps

Question 9

Disadvantage of reverse osmosis

Answer 9

Expensive due to the pressurisation

Question 10

How can fresh water be made in to potable water?

Answer 10

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

Question 11

3 ways to sterilise fresh water

Answer 11

UV
Chlorine
Ozone

Question 12

How can desalination be carried out?

Answer 12

Distillation
Reverse osmosis

Question 13

What can waste water contain?

Answer 13

Harmful microbes
Organic waste
Harmful chemicals

Question 14

What are the three types of waste water?

Answer 14

Sewage
Agricultural waste
Industrial waste

Question 15

What is the first step in processing waste water?

Answer 15

Screening and grit removal

Question 16

What is the second step in processing waste water?

Answer 16

Sedimentation

Question 17

What is sedimentation?

Answer 17

Separating water in to sludge and effluent

Question 18

How is sludge treated?

Answer 18

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

Question 19

How is effluent treated?

Answer 19

Aerobic respiration
- Bacteria are added to effluent
-These bacteria feed on organic matter and microbes

Bacteria is then removed

Discharged back to rivers

Question 20

What is biogas?

Answer 20

A mixture of methane, CO2 and hydrogen sulfide

Used as fuel

Question 21

What is phytomining?

Answer 21

Using plants to extract copper

Question 22

What is bioleaching?

Answer 22

Using bacteria to extract copper

Question 23

How does phytomining work?

Answer 23

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

Question 24

How does bioleaching work?

Answer 24

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

Question 25

Advantages of Phytomining and bioleaching

Answer 25

Avoid digging and moving large amounts of rock associated with traditional mining methods

Question 26

What type of rock is used for phytomining and bioleaching?

Answer 26

LOW GRADE ORES

(Ores with only little copper in them)

Question 27

What is a life cycle assesment?

Answer 27

LCA

A way of assessing the energy costs and environmental impact of a product over its lifetime

Question 28

What are the four stages of LCA?

Answer 28

Extracting and processing raw materials

Manufacturing and packaging

Use and operation during its lifetime

Disposal

Question 29

How can products be disposed?

Answer 29

Landfill
Incineration
Reused
Recycled