Using Resources
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What are the 4 stages of LCA
-extraction and processing the raw materials - manufacturing and packaging your products -using products -disposing of it
What are the affects on the environment for each of the four stages?
(Extraction)1 damages in environment by deforestation (Manufacturing) 2 energy used, pollution from CO2 Use(3) the damages it creates, products use Disposing(4) chemical into atmospheres on ecosystems. Less biodiversity
What are the limitations of life cycle assessments?
Lots of steps, difficult to asses As swell as being manipulated by businesses
What is potable water?
Water that is safe to drink
What 3 criteria’s classify potable water?
-There is Low level of dissolved substances -no microorganisms -the ph is between 6.5 and 8.5
What is fresh water?
Has little dissolved substance.
Can you get potable water from fresh water?
Yes
Where does fresh water come from?
Surface water and ground water
What is surface water?
Bodies of water exposed to the surface (river and lakes)
What is ground water?
Water in in aquifers Permeable rocks trap water
Why does the uk use surface water?
As it is easy to access and is replaced frequently
Why can’t Middle East use fresh water?
As the water dries up when it hot
What are the methods to filter fresh water?
• filter out big things through wire mesh -using beds of sand and gravel to filter out small bits -sterilization: by bubbling chlorine gas through it. To kill microbes
What is desalination?
Extracting potable water from sea water
How do you desalinate water?
Distillation and reverse osmosis
What is distillation (desalination version)
Distillation burns water, then condenses it in condenser (I’m large wauntitiesy
What is reverse osmosis?
Salty water passed through membrane. So large molecules are trapped and separated
what are the domestic sources of waster water?
showers, sinks and tiolets
What are the agricultural system sources of waste water?
nutrients run off from fields, animal waste
what are the industrial sources of waste water
factories
what is removed from sewage/ agricultural waste water before returning to environment?
-harmful microbes -organic matter
what are the stages to sewage treatment
1, Screening: sewage passed through meshes to remove anything large 2, Sedimentation: where sewage is left to sit in settlement tank. heavy particles settle at bottom as sludge. lighter particles settle at top as effluent. 3.Aerobic digestion: oxygen is pumped to the effluent tank filled with bacteria[producing safe water] 4. Anaerobic digestion: The sludge tank has a sealed lid to stop oxygen getting in [producing methane, that is burned as energy source]
what are the additional stages to sewage treatment?
adding chemicals and ultra violet radiation
why do poorer countries use sewege treatmant?
it is easier than desalinating salt water