Using Resources Flashcards
What do we use natural resources for
- warmth
- shelter
- food
- clothing
Potable water
Go look through the chem deck
What is a finite resource
One that will eventually run out
- coal, oil, gas
Examples of renewable energy
- solar
- wind
- wave
- tidal
- geothermal
What is potable water
Water that is safe to drink, but it still has some impurities in it
What is pure water
- odourless
- tasteless
- colourless
-only contains H2O
What does potable water contain low levels of in order to be safe
- microbes
- salts
Why is making sea water safe to drink, harder than pond water
High energy cost for removing sodium chloride from the sea water
How is potable water sterilised
- removing insoluble by passing the water through filter beds
- Microbes are killed via sterilising with:
—> chlorine
—> ozone
—> ultra violet - But you need to use the right amount of these as they can also be harmful to humans in excess
What is desalination
- turning sea water into drinking water
- this can be done via distillation or reverse osmosis
What is distillation
- heat sea water to boiling point and it evaporates
- steam rises, cools and condenses in a condensing tube
- leaving behind the salt
What are the downsides to desalination
- high energy cost of boiling water and cooling down steam in tube
- not all water evaporates = leaves salty waste water = difficult to sustainable dispose of, without harming aquatic life
What is reverse osmosis
- forcing water thru a membrane at high pressure
- the membranes tiny holes allows water through, but not ions and other molecules
- because they are too big
What is the disadvantage of reverse osmosis
- produces lots of waste water = not very effective
- membranes are expensive
What are the dangerous things in waste water
Pollutants:
- harmful bacteria
- nitrogen compounds
What are the dangerous things in industrial/agricultural waste water
- high levels of toxic metal compounds
- fertilisers
- pesticides
What are the different steps in cleaning sewage water
- Screening: removes twigs, branches and other materials
- Sedimentation: heavy solids sink to bottom of settlement tank (forming sludge), effluent stays above
- Effluent undergoes biological aerobic digestion (by pumping air thru to encourage aerobic bacteria to break down organic matter and other microbes)
- Sludge and other materials undergo anaerobic digestion: producing fertilisers and methane gas for fuel)
How do you find the mass of a dissolved solid
Mass of evaporating basin before - mass of evaporating basin of solid left behind from evaporation
What are the different stages to an LCA
- extracting and processing raw materials
- manufacturing and packaging product
- use of product
- disposal of product
Describe stage 1 of LCA - extracting and processing raw materials
- Is it finite?
- expensive energy to extract, transport then process raw material?
- scar the landscape?
- waste products harmful to local ecosystems?
Describe stage 2 of the LCA - manufacturing and packaging product
- it considers how much energy and resources are required
- energy is used in electricity, fuel, electricity
- is the pollution produced considered?
- what’s the environmental impact of transporting the goods from factory to customer?
Describe stage 3 of the LCA - use of product in lifetime
Depends on product
- car has a large impact: uses fuel = finite resource = bad
- wooden chair has a relatively small impact: made from a renewable resource = good
Describe stage 4 of the LCA - disposal of product
- landfill = high environmental impact
- incineration = low-ish environmental impact
- Recycling = good, no new compounds have been taken from environment
What are the disadvantages of comparative LCAs
- opinion based: people may disagree
- companies producing the product are biased: may hide certain important details
