Term 6 - 10C10 Using Resources

What are finite resources?

Resources that aren't formed quickly enough to be considered replaceable

What are renewable resources?

Resources that are reformed or replenished as they are used

What are natural resources?

Resources that form without human input

What is sustainable development?

Development that meets the current needs without limiting future needs

What is potable water?

Water that is safe to drink

What is desalination?

The removal of salt from water

Is potable water pure?

No - it contains dissolved substances

What is the main source of fresh water in the UK?

Rain water that collects in the ground and in rivers and lakes

Outline the three steps in producing potable water from fresh water

1. Choose a source of fresh water

2. Passing water through filter beds

3. Sterilising it

Why is fresh water passed through filter beds when making potable water?

To remove any solid material

Why is fresh water sterilised when making potable water?

To kill microbes

If supplies of fresh water are limited, how will potable water be generated?

Taking salt out of salt water or sea water

How is salty water desalinated?

Either by distillation or reverse osmosis (both process remove salt)

How can fresh water be sterilised?

Either by chlorine, ozone or UV light

Why is it better to generate drinking water from fresh water than salty water?

Removing salt from salty water requires lots of energy

How can you test if water is pure?

Check if the melting point is 0 ᵒC and the boiling point at 100 ᵒC

How is sewage treated?

1. Screening to remove any large material

2. Sedimentation to produce sludge and effluent

3. Sludge undergoes anaerobic digestion to produce natural gas and fertiliser

4. Effluent undergoes aerobic digestion to produce water

What happens when sludge undergoes anearobic digestion?

The organic matter in sludge is broken down producing natural gas and fertiliser

What happens when effluent undergoes aerobic digestion?

The organic matter in effluent is broken down producing water

Why are life cycle assessments carried out?

To assess the environmental impact of the life of a product

What are the main stages of a life cycle assessment?

consider the environmental impact of products during:

• extracting and processing raw materials

• manufacturing and packaging

• use and operation during its lifetime

• disposal at the end of its useful life, including transport and distribution at each stage.