Using resources

• Potable water 


  Safe for human consumption
• To make water potable we have to

  Drastically reduce the microbes found in it

  Reduce concentrations of dissolved minerals and salts but don't eradicate them completely

  It does not have to be chemically pure
• Sources of potable water

  Fresh water - only needs filtering and sterilising and is the easiest source to treat

  Seawater - most expensive to treat due to the large amounts of energy needed for desalination

  Waste water - although treatment of waste water involves many steps less energy is used than desalination
• Potable water in Saudi Arabia

  Rainfall levels are low so fresh water cannot be relied on

  Seawater is used as an alternative to fresh water

  Seawater must be desalinated and there are 2 methods

  The major disadvantage to both desalination methods is that they need a high amount of energy making them expensive
• Desalination 


  Distillation: boiling seawater creates steam which then condenses giving pure water

  Reverse osmosis: seawater is passed through a selective membrane which only allows water molecules through
• Desalination 


  Distillation

  
• Desalination 


  Reverse osmosis

  
• The earth's natural resources form without human assistance. They usually come from the earths crust, oceans or atmosphere and are sued for energy, building materials and food
• Natural renewable resources 


  Renewable resources are regenerated at the same rate or faster than they are used some of these include:

  • Timber
  • Fresh water
  • Food
• Natural non-renewable resources 


  Non-renewable resources are regenerated at a much slower rate than we use them. Examples include:

  Fossil fuels

  Nuclear Fuels

  Metal ores
• The human population on Earth has increased rapidly in the last 100 years forcing us to find ways to supplement the Earths natural resources
• Agriculture 


  Agriculture is the main example of Supplementation

  Natural food products are now available in much larger quantities because of the organisation of agriculture
• Synthetic products 


  The development of useful synthetic products has reduced our reliance on natural products

  E.g. man-made polymers have gradually replaced rubber in tyres
• Domestic sources of waste water 


  Washing up, using the toilet, and having a shower are all activities which produce waste water

  Treatment removes the organic matter ad harmful microbes found in this waste
• Agricultural sources of wastewater

  Nutrient run-off and slurry are two major sources of agricultural waste water

  Similarly to domestic waste water, organic matter and harmful microbes must be removed prior to releasing this water back into fresh-water sources
• Industry sources of waste water

  The harbour process is an example of an industrial process that produces a lot of waste water

  Additional treatment stages are required for industrial waste water as it often contains harmful chemicals
• Sewage treatment 


  To avoid polluting our environment, we must treat sewage before releasing it into the environment. The steps in the sewage treatment process are:

  Screening - Sewage is examined to remove grit and large items

  Sedimentation - This results in the separation of sewage into heavier sludge and lighter effluent

  Sludge - anaerobically digested by bacteria

  Effluent - aerobically digested by bacteria
• Metal ores


  Finite resources and the availability of metal ores is rapidly decreasing. Mining is the traditional method used to extract ores from the ground, but this process causes significant environmental damage
• Environmental damage from metal ore extraction

  Habitat destruction - destroyed by mining and this then threatens biodiversity

  Pollution - mining creates a lot of noise and air pollution

  Landscape scars - Large mounds of rock are left behind, scarring the landscape
• Properties of Copper

  • Good conductor of heat
  • Good Conductor of electricity
  • Malleable
  • Unreactive - doesn't react with water meaning it has longevity
• Copper overexploitation 


  Copper-rich ores are in short supply because of historical overexploitation

  Consequently, we have had to find new ways of extracting copper from low-grade ores and contaminated lands
• Phytomining 


  Allows us to extract copper from contaminated land

  Plants growing on contaminated land absorb copper ions as they grow

  These plants are harvested and burned, producing ash that contains high concentrations of copper compounds
• Bioleaching


  Improved our ability to extract copper from low-grade ores

  Bacteria are mixed in with low-grade ores

  The bacteria convert the copper into a solution rich in copper compounds called leachate solution

  A disadvantage of bioleaching is that the process is very slow
• Life cycle assessments 


  LCAs assess every stage of a product's lifetime in order to evaluate total environmental costs

  There are four stages to be considered

  • Acquiring raw materials
  • Manufacturing and packaging
  • Product use
  • Product Disposal
• Difficulties associated with LCAs

  Some aspects like energy use and raw materials can be easily quantified, others can be more difficult to estimate

  Most LCAs have subjective parts to them meaning they can be biased

  Selective LCAs only use or quantify some of a products environmental impact

  These can be exploited by biased companies to give them a positive brand image
• Reusing and recycling can

  Reduce waste production

  Reduce environmental impact - Resource extraction can cause significant environmental damage. more recycling can reduce resource extraction

  Increased efficiency - in terms of both cost and energy consumption

  Sustainability - ensure the preservation of raw materials for use by future generations
• Recycling metals 


  The process of recycling involves melting metals before reshaping them. Recycling is preferable to mining and extracting new resources for the following reasons:

  • Less energy required
  • Fewer waste rock heaps
  • Reduced burning of fossil fuels
  • Conserves finite resources
• Reducing the use of Glass 


  Some glass products such a bottles cant be reused as they are but they can be recycled

  The four steps are:

  • Crush
  • Sort - into colour and chemical composition
  • Melt
  • Reshape