C14 Earth's resources Flashcards
What are finite and renewable resources?
Finite resources are natural resources that are limited in supply and will eventually run out, such as fossil fuels (coal, oil, natural gas) and metal ores and rocks and minerals.
Renewable resources are natural resources that can be replenished over time, such as solar energy, wind energy, and biomass.
What is potable water?
Potable water is water that is safe to drink, meeting strict safety standards for levels of minerals and microorganisms.
What is the difference between potable water and pure water?
Potable water is safe for drinking and may contain some dissolved minerals, while pure water contains no impurities or dissolved substances.
How is fresh water obtained from underground sources?
Fresh water is obtained from underground sources called aquifers by drilling a pipe to form a water well.
What are the main steps in treating water from a reservoir to make it potable?
Screening the water to remove large objects
Settlement tank so sand and soil settle out
Aluminium sulfate and Lime added to make dirt clump together so that they sink to the bottom of the water
Water passed through a filter made of sand to filter out remaning dirt
Water is sterilised using chlorine,ozone or UV
What is desalination?
Desalination is the process of converting salty water, such as seawater, into potable water.
Why is distillation an expensive process for desalination?
Distillation is expensive due to the high energy costs involved in boiling large volumes of water, even though reduced pressure lowers the boiling point.
What is reverse osmosis, and how does it work?
Reverse osmosis is a desalination process that uses membranes to separate water from dissolved salts. It removes up to 98% of dissolved salts and requires energy to pressurise the water.
What are the advantages of reverse osmosis over distillation?
Reverse osmosis uses less energy than distillation because it does not involve heating, but it still requires energy to pressurise the water.
Where is desalination commonly used?
Desalination is commonly used in the Middle East and on islands with limited natural fresh water sources.
What is flash distillation?
Flash distillation is a desalination process where water is boiled under reduced pressure, allowing it to boil below 100°C and saving energy.
What is the steps in waste water treatment?
-Screening, where large solid objects and grit are removed from the waste water using a metal grid.
-Sedimentation-Solid sediments settle out from the mixture, and sludge is pushed to the center of the tank and piped to a storage tank for further treatment.The watery liquid known as Effluent is further treated.
-Aeration-Useful bacteria break down remaining organic matter and harmful microorganisms aerobically (in the presence of oxygen).The tank is aerated by bubbling air into the effluent.
-Useful bacteria settle out as sediment, which is either recycled or passed to the sludge treatment tank. The treated water is safe to discharge into rivers.
What can be used from the sludge by product of wastewater treatment?
We treat the sludge using a process called ‘anaerobic digestion’. This heats the sludge up to high temperatures, encouraging the bacteria inside to break down the waste. This creates biogas that we can then burn to create heat, which in turn creates electricity.
Alternatively dry the sludge into blocks called ‘cake’, which are then burned to generate heat. We capture this heat and turn it into electricity.
We can also use it for fertilisers
What is smelting?
Smelting is the process of extracting metal from its ore by heating it beyond its melting point, often with a reducing agent like coke, to separate the metal from impurities.
What is bioleaching?
Bioleaching is the process of using microorganisms (e.g., bacteria) to extract metals from their ores by breaking down the mineral structure. Electrolysis is used to further extract copper from the impure leachate.
What are the 2 ways of extracting copper from low grade copper ores?
Bioleaching and phytomining
What is Phytomining?
Phytomining is the process of using plants to absorb metal ions from the soil, which are then harvested and burned to extract the metals.
What are the pros and cons of bioleaching?
pros
Low energy requirements.
Environmentally friendly compared to traditional smelting.
Can extract metals from low-grade ores.
Cons
Slow process compared to smelting.
Requires careful control of conditions (e.g., pH, temperature).
Produces acidic waste that must be managed.
How does phytomining work?
Plants absorb metal ions through their roots and store them in their tissues. The plants are then harvested, dried, and burned to produce ash containing concentrated metal compounds.
Pros and Cons of Phytomining
Pros:
Environmentally friendly and sustainable.
Can extract metals from low-grade ores or contaminated soils.
Low energy requirements compared to traditional mining.
Cons:
Slow process (takes years for plants to grow).
Limited to specific metals and soils.
Requires large areas of land for cultivation.
What is a common environmental benefit of both bioleaching and phytomining?
Both methods are more environmentally friendly than traditional mining and smelting, as they produce less pollution and can use low-grade ores.
What is a Life Cycle Assessment (LCA)?
LCA is a technique used to assess the environmental impact of a product, process, or service throughout its entire life cycle, from raw material extraction to disposal.
What are the four main stages of a product’s life cycle in an LCA?
Raw material extraction
Manufacture
Use
Recycle/Waste management
what environmental impacts are considered in an LCA?
Atmospheric emissions
Waterborne wastes
Solid wastes
Energy dissipation
Other byproducts
