Using The Earths Resources Flashcards
(18 cards)
Potable water
Safe for humans to drink
How to make water potable
Drastically reduce number of microbes in it
Reduce concentrations of dissolved minerals and salts but don’t take them out completely
Potable doesn’t mean chemically pure. Chemically pure water would only have h20 molecules
Sources of potable water
Fresh water - only needs filtering and sterilising
Seawater - most expensive because of large amounts of energy needed to get the salt out of it
Waste water - temreatment involves many steps
Less energy to treat then treating seawater
Potable water resources in the UK
Rainfall
Levels of rainfall are high and rain is a type of fresh water so it doesn’t take much energy to make it potable
Potable water proces in UK
Collect fresh water from source not near to any heavy polluted areas
Filtrate it - solid particles are stopped
Sterilise it - harmful microbes killed
Potable water resources in Saudi Arabia
Seawater
Rainfall levels are low so supplies of fresh water cannot be relied on
Therfore seawater is used as the alternative
Treating seawater
Must me desalination ( have salt removed) by one of two methods
- Distillation - boiling seawater creates steam which condenses to give pure water
- Reverse osmosis - a Selective membrane only allows water molecules to pass through so larger molecule eg salt can’t get through
Their high energy demands means that both costs are high
Natural resources
Form without human involvement
Two categories
Renewable resources:
Don’t run out as they are generated quicker than they are used. Eg timber, fresh water, food
Non renewable resources:
Regenerated at a much slower rate than we use them. Eg fossil fuels, nuclear fuels, metal ores
Supplements to natural resources
Agriculture- natural food froducts are now available in much larger quantities bacuse of the organisation of agriculture
Synthetic products - development of synthetic products has reduced our reliance on natural resources
Domestic sources of waste water
Washing up, using the toilet, taking a shower.
Agricultural sources of waste water
Nutrient runoff and slurry
Industrial sources of waste water
Haber process
Other chemical reactions process
Sewage treatment
To avoid polluting environment we must treat sewage before it returns to the environment
Screening - sewage is examined to remove grit and large items
Sedimentation - results in the separation of sewage into heavier sludge and lighter effluent
Sludge vs effluent
Sludge is anaerobically digested by bacteria
Heavier
Effluent is aerobically digested by bacteria
Lighter
Metal ore extraction
Metal ores are non renewable and availability is rapidly decreasing
Mining is the traditional method of extraction but it causes environmental damage eg:
Habitat destruction
Pollution - makes lots of noise and pollutes air
Landscape scars - large mounds of rocks are left behind scarring the landscape
Properties of copper that make it important
Conducts electricity and heat well
Malleable
Unreactive - no reaction when it’s combined with water. Means it has a long useful lifespan
Copper overexploitation
Copper rich ores are in short supply due to historical overexploitation
Consequently we have to find new ways to extract copper from low grade ores ( ore that doesn’t contain much copper)
Alternate extraction methods of copper
Phytomining - technique that allows us ti extract copper from contaminated land
Method:
Plants growing on contaminated land absorb copper ions as they grow
These plants are harvested and burnt producing ashes that contains high concentration of copper compounds
Bioleaching - improves our ability to extract copper from low grade ores
Method:
Bacteria is added in with low grade ores
Bacteria break down the ores to create a solution rich in copper compounds. We can easily extract copper from the compound
Disadvantage of both is that they are much slower than original methods
