using resources

• what is sustainable development?

  It meets the needs of the current generation without compromising the ability of the future generations to meet their own needs.
• what needs to be at low levels so it is safe for humans to

  Microorganisms and dissolved salts in water
• what word describes water that is good quality sand safe to drink?

  potable
• where in the uk is potable water produced?

  -fresh water from a sustainable source: lakes, rivers

  -passes through a filter bed to remove solid particles

  -chlorine gas is added to kill any harmful microorganisms

  -fluoride is added to reduce tooth decay
• what things can be used to sterilise water?

  Ozone and Ultraviolet
• how can you improve the taste and quality of tap water?

  More dissolved substances can be removed by passing water through a filter containing carbon, silver and ion exchange resins
• how can seawater become pure?

  It can be desalinated through distillation or reverse osmosis
• what is a disadvantage of using reverse osmosis and distillation to purify seawater?

  It requires lots of energy which can be very expensive
• what happens during distillation?

  Water is boiled to produce steam, the steam is condensed to produce pure liquid water
• what must happen to waste water before it returns back to the environment?

  Must be treated
• what does sewage treatment require?

  -screening and grit removal

  -sedimentation to produce sewage sludge and effluent

  -anaerobic digestion of sewage sludge

  -aerobic biological treatment of effluent
• why is copper good for extracting metals?

  -good conductor for electricity and heat

  -easily bent, but hard enough to make water pipes and tanks

  -doesn't react with water do will last a long time
• how might copper be extracted?

  -heating copper-rich ores with carbon in a furnace (smelting) then can be purified by electrolysis

  -can be obtained from solutions of copper salts by electrolysis

  -displacement using scrap iron
• what has happened in the past which meant copper is running out?

  extensive mining of copper
• what is phytomining?

  method that uses plants to absorb copper:

  -as plants grow they absorb and store copper

  -the plants are then burned and the ash produced contains copper in high quantities
• what is bioleaching?

  Uses bacteria to extract metals from low-grade ores (contain small amounts of copper):

  -a solution containing bacteria is mixed with a low-grade ore

  -the bacteria converts the copper into a solution which the copper can easily be extracted from
• what are advantages of bioleaching and phytomining?


  More environmentally friendly than traditional mining methods as they do not waste materials as much
• what does a lifecycle assessment do?

  assesses the environmental impact a product has over its whole lifetime
• what does a LCA provide us with?

  A way of comparing several alternative products to see which one causes the least damage to the environment
• what do scientists need to know to carry out a LCA?

  the impact of:

  -extracting the raw materials

  -processing the raw materials

  -manufacturing the product

  -how the product is used

  -how the product is transported

  -how the product is disposed of at the end of its life
• why may an LCA not be accurate?

  Some aspects are difficult to quantify and involve value judgements, such as the impact of pollutant in the environment
• why should we recycle?

  -save money and energy

  -make sure natural resources are not used up unnecessarily

  -reduce the amount of waste produced

  -reduce the damage to the environment caused by extraction
• how may somethings be reused?

  -waste glass can be crushed and melted

  -waste plastics can be recycled to make fleece material

  -metals can be recycled by melting them down into new objects
• what is a benefit of recycling?

  Uses far less energy than the initial extraction and production processes, so less fossil fuels are burned and less greenhouse gases are released into the atmosphere, preserving raw materials for the future
• we use resources to provide warmth, shelter, food and transport
• these resources are produced by agriculture
• finite means it cannot be replaced as quickly as they are being uses up
• fossil fuels are an example for finite resources
• metals are also finite resources
• renewable means we can replace the resources as quickly as we use them
• sustainability means we can meet our needs without preventing future generations from meeting their own
• drinking water has to have low levels of dissolved salts, no microorganisms, and a pH between 6.5 and 8.5
• potable water is water safe to drink
• pure water contains no dissolved substances at all which makes it not safe
• to produce potable water:

  1. find a good source of fresh water, eg a river
  2. pass the water through filter beds to remove materials such as leaves and suspended particles
  3. water is then sterilised to remove microbes using either chlorine, ultraviolet or ozone
• sea water has high levels of dissolved minerals which means potable water is then produced by desalination
• desalination reduces the level of dissolved minerals so it reaches an acceptable level to become potable
• to carry out desalination use simple distillation or reverse osmosis
• both distillation and reverse osmosis reduce the levels of dissolved minerals but require lots of energy making them expensive
• waste water contains large amount of organic molecules and harmful microorganisms