Using Resources

combined science

?
View mindmap
  • Using Resources
    • life cycle assessments
      • looks at every stage of a products life to assess the impact it would have on the environment
      • problems
        • the use of energy, some natural resources and the amount of certain types of waste produced by a product over a lifetime can be easily quantified. but the effect of some pollutants is harder to give a numerical value
          • producing a life cycle assessment is not an objective method as it takes into account the values of the person carrying out the assessment - LCAs can be biased
        • selective LCAs only show some of the impacts of a product on the environment can also be biased as they are written to deliberately support the claims of a company - to give them + advertising
      • getting the raw materials
        • manufacture and packaging
          • using the product
            • product disposal
              • getting the raw materials
                • manufacture and packaging
                  • using the product
                    • product disposal
                      • products are often disposed of in landfill sites - takes up space an pollutes land and water
                      • energy is used to transport waste to landfill - causes pollutants to be released into the atmosphere
                      • products might be incinerated - causes air pollution
                    • the use of a product can damage the environment
                    • how long a product is used for or how many uses it gets is also a factor - products need lots of energy to produce but are used for a long time means less waste in the long run
                  • can use a lot of energy resources and can also cause pollution
                  • need to think about any waste products and how to dispose of them. the chemical reactions used to make compounds from their raw materials can produce waste products
                    • some waste can be turned into other useful chemicals
                • can damage the local environment and can result in pollution due to amount of energy needed
                • often need to be processed to extract the desired materials - often needs large amount of energy
              • products are often disposed of in landfill sites - takes up space an pollutes land and water
              • energy is used to transport waste to landfill - causes pollutants to be released into the atmosphere
              • products might be incinerated - causes air pollution
            • the use of a product can damage the environment
            • how long a product is used for or how many uses it gets is also a factor - products need lots of energy to produce but are used for a long time means less waste in the long run
          • can use a lot of energy resources and can also cause pollution
          • need to think about any waste products and how to dispose of them. the chemical reactions used to make compounds from their raw materials can produce waste products
            • some waste can be turned into other useful chemicals
        • can damage the local environment and can result in pollution due to amount of energy needed
        • often need to be processed to extract the desired materials - often needs large amount of energy
    • Potable water
      • water you can drink
      • not pure as it contains dissolved substances
      • how its produced
        • when it rains water is collected as surface water (lakes, rivers and reservoirs) or as groundwater (in rocks called aquifers that trap water underground)
          • in the UK the source of fresh water depends on location - surface water dries up first so eg. in the south east most of the domestic water supply comes from groundwater
          • in some very dry countries theres not enough surface or groundwater and instead seawater must be treated by desalination
            • seawater can also be treated by processes that use membranes - like reverse osmosis
              • the salty water is passed through a membrane that only allows water molecules to pass through
              • both methods need lots of energy - very expensive and not practical for mass production
            • both methods need lots of energy - very expensive and not practical for mass production
        • filtration - a wire mesh screens out large twigs etc. and then gravel and sand beds filter out any solid bits
          • sterilisation - the water is sterilised to kill any harmful bacteria or microbes - can be done by bubbling chlorine gas through it or by using ozone or ultraviolet light
    • waste water treatment
      • sewage treatment:
        • diagram*
        • 1. the sewage is screened - removing any large bits of material as well as grit
          • 2. then it stands in a settlement tank and undergoes sedimentation - the heavier suspend solids sink to the bottom to produce sludge while the lighter effluent floats to the top
            • 3. the effluent in the tank is removed and treated by biological aerobic digestion  - where air is pumped through the water to encourage aerobic bacteria to break down any organic matter
              • 4. the sludge from the bottom of the tank is removed and transferred into large tanks - gets broken down by bacteria in a process called aerobic diestion
                • 5. aerobic digestion breaks down the organic matter in the sludge, whilst releasing methane gas - the methane gas can be used as an energy source and the remaining digested waste can be used as fertiliser
                  • 6. for waste water containing toxic substances - might need to add chemicals, UV radiation or using membranes
        • can be used as an alternative in areas where there's not much fresh water
      • where it comes from
        • when you flush water down the drains in your house it goes into the sewers and towards sewage treatment plants
        • agricultural systems produce a lot of waste water including nutrient run-off from fields and slurry from animal farms
        • sewage from domestic, industrial and agricultural sources have to be treated to remove any organic matter and harmful microbes before it can be put back into freshwater sources
        • industrial processes also produce a lot of waste water that has to be collected and treated
    • natural resources
      • includes anything that comes from the earth, sea and air - form without - human input
      • can be replaced by synthetic products or improved upon by man-made processes
      • agriculture provides conditions where natural resources can be enhanced for our needs
      • some will run out:
        • renewable resources
          • reform at a similar rate to or faster than, we use them
          • eg. fresh water and food
        • finite (non-renewable) resources
          • aren't formed quickly enough to be considered replaceable
          • include fossil fuels and nuclear fuels such as uranium and plutonium , metals and minerals found in ores in the earth
          • after they've been extracted, many finite resources undergo man-made processes to provide fuels and materials necessary for modern life
      • risks of extracting finite resources
        • people have to balance social, economic and environmental effects
    • reuse and recycling
      • sustainable development
        • an approach to development that takes account of the needs of present society while not damaging the lives of future generations
        • using, processing and extracting resources can be unsustainable
          • extracting - due to the amount of energy used and waste products produced
          • processing - amount of energy used from finite resources
        • one way of reducing finite resources is for people to use less
          • we cant stop using them  altogether but chemists can develop and adapt processes that lower amounts of finite resources and reduce damage to the environment
      • copper ores
        • copper is a finite resource
        • to improve its sustainability you can extract it from low grade ores (ores without much copper)
          • bioleaching
            • bacteria are used to convert copper compounds in the ore into soluble copper compounds, separating out from the copper ore in the process
              • the leachate (solution produced) contains copper ions which can be extracted
          • phytomining
            • this involves growing plants in soil that contain copper - plants cant use or get rid of it so it gradually builds up in the leaves
              • the plants can be harvested, dried and burned in a furnace- the ash contains soluble copper compounds which copper can be extracted by electrolysis or displacement
          • traditional methods are damaging to the environment - the new methods have smaller impacts but they're slow
      • recycling metals
        • mining and extracting metals takes lots of energy
        • recycling metals uses much less energy - conserves the finite amount of each metal in the earth and cuts down amount of waste getting sent to landfill
        • metals are usually recycled by melting them and then casting them into the shape of the new product
        • depending on what the metal will be used for after recycling, the amount of separation required can change
      • recycling glass
        • reduces the amount of energy needed to make new glass products and amount of waste created when used glass is thrown away
        • glass bottles can be reused without reshaping
        • other forms of glass cant be reused so they're recycled instead - usually separated by colour and chemical composition before being recycled
        • the glass is crushed and then melted to be reshaped for use

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all using resources resources »