Topic C10 - Using resources Flashcards
What are renewable resources
Reform at a similar rate to or faster than we used them
One of the finite resources
Aren’t formed quickly enough to be considered replaceable
What are some examples of finite resource
Fossil fuel and nuclear fuels such as raining and plutonium minerals and metals are found in Ores
Are the risks of extracting finite resources
Many modern materials are made from raw, finite resources
People have to balance the social, economic and environmental effects of acting finite resources
Mining metal ores is good because useful products can be made. It was a provides local people with jobs and brings money into the area. However mining ores is it bad for the environment as loads of energy is used, scars the landscape and produces loads of waste and destroys habitats
How is chemistry helping improve sustainability
Sustainable development is an approach to development that takes account of the needs of the present society while not damaging the lives of future generations
As well as using resources, extracting resources can be unsustainable because of the amount of energy that is wasted. Processing the resource into useful materials can be unsustainable to as the process often uses energy that is made from finite resources
We can’t stop using finite resources altogether but chemists can develop and adapt processes that use low amount of finite resources and reduce damage to the environment
What are some sustainable ways of extracting from metal ores that are finite
By extracting from low-grade ores (ores without much metal in it)
By using bioleaching and phytomining
Traditional methods of mining are pretty damaging to the environment. These new methods of extraction have a much smaller impact but the disadvantage is that they are slow
What is bioleaching
Bacteria are used to convert metal compounds in the ores into stable metal compounds, separating out the metal from the ores in the process.
The leachate (the solution produced by the process) contains metal ions, which can be extracted by electrolysis or displacement with a more reactive metal
Why is recycling metals important
Mining and extracting metals take loads of energy most of which come from burning fossil feels
Recycling metals often use much less energy than is needed to mine and extract new Metal, conserves The finite amount of each metal in the Earth and cut down on the 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 for recycling can change
What is phytomining
This involves growing plants in soil that contains the metal.
The plant can’t use all get rid of the metal so it gradually builds up in the leaves.
The plant can be harvested, dried and burnt in a furnace
The ash contains soluble metal compounds from which metal can be extracted by electrolysis or displacement
How is glass recycled
Glass bottles can often be reused without reshaping
Other forms of glass can’t be reused so they’re recycled instead. Usually the glass is separated by colour and chemical composition before being recycled
The glass is crushed and then melted to be reshape to use in glass products such as bottles or jars. It might also be used for a different purpose such as insulating glass wood for wall insulation in homes
What is life cycle assessments and that are the stages in it
A life cycle assessments looks at every stage of a products life to assess the impacts it would have on the environments
1) Getting the Raw materials
2) manufacturing and packing
3) using the product
4) product Disposal
what do you need to consider in the “ getting the raw materials “ stage of the LCA
Extracting the raw materials needed for a product can damage the local environment. Extraction can also result in pollution due to the amount of energy needed
Raw materials often need to be processed to extract the desired materials and this often needs large amount of energy
what do you need to consider in the “ manufacturing and packaging “ stage of the LCA
Manufacturing products and their packaging can use a lot of energy resorces And can also cause a lot of pollution
You also need to think about any waste products and how to dispose of them. The chemical reactions used to make compound from the raw material can produce waste products. Some waste can be turned into other useful chemicals, reducing the amount that ends up polluting the environment
what do you need to consider in the “using the product “ stage of the LCA
The use of a product can damage the environment. Fertilisers can leach into streams and rivers causing damage to ecosystems
How long a product is used for and how many years it gets is also a factor-products that need loads of energy to produce but are used for ages mean less waste in the long run
what do you need to consider in the “product disposal “ stage of the LCA
Products are often disposed of in landfill sites. This takes up space and pollutes land and water
Energy is used to transport waste to landfill which causes pollutants to be released into the atmosphere
Products might be incinerated which causes air pollution
What’s the problem with LCA
The use of energy, some natural resources and the amount of certain type of waste produced by a product over its lifetime can be easily quantified. By the affect of some pollutants is higher to give a numerical value
So, producing and LCA is not an objective method as it takes into account the values of the person carrying out the assessment. This means LCAs are biased
Selective LCAs which only shows some of the impact of a product on the environment can also be biased as they can be written to deliberately support the claims of a company, in order to give them positive advertising
What is potable water
The water is water that’s been treated or is Natalie safe for humans to drink-it’s essential for life
Potable water contains loads of other dissolved substances
The important thing is that the level of dissolved Salt is it too high, it has a pH between 6.5 and 8.5 and also that there aren’t any nasty things around in it
What is pure water
Your water only contains H2O molecules
How is potable water process
Rainwater is a type of freshwater. Freshwater is water that doesn’t have much dissolved in it
When it rains water can either collect as surface water (in lakes, rivers and reservoirs) or as ground water
In the UK the source of freshwater used depends on location. Surface water tends to dry up first so in the warm areas most of the domestic water supply come from ground water
Even though it only has low levels of dissolved substances, water from these freshwater sources still need to be treated to make it safe before it can be used in this process includes :
- location-a wire mesh screen out large twigs and then gravel and sand beds filter out any other solid bits
- sterilisation-the water is there lies to kill any harmful bacteria or microbes. This can be done by bubbling chlorine gas through it or use ozone or ultraviolet light
In some very dry country there is not enough surface or ground water and instead seawater must be treated by distillation to provide portable water
Seawater can also be treated using membranes-like a reversible osmosis. The salty water is passed through a membrane that only allows water molecules to pass through. Ions and larger molecules are trapped by the membrane so separated from water
Both of these processes need loads of energy and really expensive and not practised for producing large quantities of freshwater
Where does wastewater come from
It is when you flush water down the drain it goes into this sewers and towards sewage treatment plants
Agricultural Systems also produce a lot of waste water including natural run-off from fields and slurry from animal farms
Sewage from domestic and agricultural sources have to be treated to remove any organic matter and harmful microbes before it can be put back into freshwater sources like rivers and lakes. Otherwise it would make them very polluted and would pose health risks
Industrial processes also produce a lot of waste water that has to be collected and treated
As well as organic matter industrial wastewater can also contain harmful chemicals-so it has to undergo additional stages of treatment before it is safe to release it into the environment
What are the stages of sewage treatment
Before being treated the sewage is screened -this involves removing any large bits of material as well as any grit
Then it’s allowed to stand in a settlement tank and undergoes sedimentation-the heavier suspended solids sink to the bottom to produce sludge while the lighter effluent floats on the top.
The effluent in the sediment tank is removed and treated by biological aerobic digestions. This is when air is pumped through the water to encourage aerobic bacteria to break down any organic matter-including other microbes in the water
The sludge from the bottom of the settlement tank is also removed and transferred into large tanks. Here it gets broken down by bacteria is in a process called anaerobic digestions
Anaerobic digestion breakdown of the organic matter in the sludge, releasing methane gas in the process. The methane gas can be used as an energy source and the remaining digestive waste can be used as fertiliser
For water waste containing toxic substances additional stages of treatment may involve adding chemicals, UV radiation or using membranes
