Using Resources

• The human population is increasing rapidly and our use of earth's finite resources has increased. If humans continue to use these resources at the rate at which we are, then we will reach a point where the human population cannot be sustained on earth.
• Resources humans use


  • Warmth
  • Shelter
  • Food
  • Clothing
  • Transport
• Scientists are making technological advances in agricultural and industrial processes to provide food and other products that meet the growing needs of the human population but it is of major importance that this is done in a sustainable way so that our finite resources are not used up.
• Finite resources


  Resources of which there is a limited supply, e.g. coal, oil and gas
• Renewable resources


  Resources that will not run out in the near future because the reserves of these resources are high, e.g. solar energy, wind power, hydropower and geothermal energy
• Crude oil processing


  1. Fractional distillation

  2. Cracking
• Crude oil is processed through fractional distillation and cracking to produce many useful materials such as petrol, diesel and kerosene.
• Potable water


  Water that is safe to drink
• Pure water


  A substance that contains only a single type of material that has not been contaminated by another substance
• Potable water must contain low levels of microbes and salts for it to be deemed safe to consume. This is because high levels of microbes and salts can be harmful to human health.
• The methods of making water safe vary depending on where you live. Starting with sea water is harder than starting with fresh water. This is because the energy cost of removing large amounts of sodium chloride from seawater is greater.
• In the UK, our populations' water needs are met through rainfall. During the summer, water levels in reservoirs decrease and local areas are encouraged to reduce their water usage by swapping baths for showers and they are asked to avoid using hosepipes.
• Removing impurities from naturally occurring fresh water in the UK


  1. Passing it through filter beds

  2. Sterilising the water using chlorine, ozone or ultraviolet light
• Scientists often discover new ways to produce a product; synthetic methods of production replace natural methods. For example, fertilisers were obtained from manure (a natural resource). The Haber process allowed the synthetic production of fertilisers and this enabled intensive farming methods to spread across the globe. In turn, this supported the growing human population.
• Copper is another resource that has been exploited over time. As the human population has increased since 1900, the demand for copper has also increased. Copper is a finite resource which means that there is a limited supply.
• Desalination of sea water

  1. Distillation

  2. Reverse osmosis
• Osmosis


  The movement of particles from an area of high concentration to an area of low concentration through a semi-permeable membrane
• Reverse osmosis involves forcing water through a membrane at high pressure. Each membrane has tiny holes within it that only allow water molecules to pass through. Ions and other molecules are prevented from passing through the membrane as they are too large to fit through the holes.
• The disadvantage of reverse osmosis is that it produces large amounts of wastewater and requires the use of expensive membranes. Due to a large amount of wastewater produced, the efficiency of this method is very small.
• Water treatment before release back into the environment

  1. Screening to remove material such as branches, twigs and grit

  2. Sedimentation to remove heavier solids

  3. Aerobic digestion of organic matter

  4. Anaerobic digestion of sludge
• Analysing water samples


  1. Testing pH

  2. Measuring mass of dissolved solids

  3. Distillation
• Life-Cycle Assessment (LCA)


  Follows the four main stages of the life cycle of a product: 1) Extracting and processing raw materials, 2) Manufacturing and packaging, 3) Use, 4) Disposal

  
• The disadvantage of comparative LCAs is that some parts of it require certain judgements to be made. Different people have different opinions and this is dependent on who completes the LCA and whether a certain level of bias is added.
• Biological extraction methods


  Methods that use plants (phytomining) or bacteria (bioleaching) to extract metals, with lower environmental impact than mining
• Advantages of recycling


  • Fewer resources needed to extract raw materials

  Less energy used compared to making new products

  Less greenhouse gases produced

  Less waste going to landfill
• Disadvantages of recycling


  • Collection and transport of goods requires staff, vehicles and fuel

  Sorting materials can be difficult to achieve high purity

  Some materials like steel don't require high purity for some uses