C14: The Earth's Resources Flashcards
What do humans use the Earth’s resources for?
Warmth, shelter, food and transport
What do natural resources provide?
Food, timbre, clothing and fuels
What do finite resources do?
They are processed to provide energy and materials
What is sustainable development?
The development that meets the needs of current generations without compromising the ability of future generations to meet their own needs
What should drinking water for humans have?
Sufficiently low levels of dissolved salts and microbes
Why is potable water not pure water?
Because it contains dissolved substances
How is most potable water produced?
By choosing an appropriate source of fresh water, passing the water through filter beds and desalination (sterlising)
What are the sterilising agents used for potable water?
Chlorine, ozone or UV light
What may be required if supplies of fresh water are limited?
Desalination of salty water or sea water
How can desalination be done?
By distillation or by processes that use membranes such as reverse osmosis
What does sewage and agricultural waste water require?
Removal of organic matter and harmful microbes
What does sewage treatment include?
Screening and grit removal, sedimentation to produce sewage sludge and effluent, anaerobic digestion of sewage sludge and aerobic biological treatment of effluent
What are ways of extracting copper from low-grade ores?
Phytomining and bioleaching
What is phytomining?
The process of using plants to absorb metal compounds. These plants are harvested then burned to produce ash that contains metal compounds
What is bioleaching?
The process of using bacteria to produce leachate solutions that contain metal compounds
How can the metal compounds from phytomining and bioleaching obtain the metal?
By displacement using scrap iron or by electrolysis
Why are Life Cycle Assessments carried out?
To access the environmental impact of products in the extraction of raw materials, manufacturing and packaging, use and operation during its lifetime and the disposal at the end of its useful life
What should we not do in order to save lives of future generations?
Using up all limited resources, increasing global warming and damaging the environment
Is recycling free?
No
What are the requirements of potable water?
pH of between 6.5 and 8.5, low levels of dissolved substances and no microorganisms
What are benefits of surface water?
It is replaced by the rain often and easy to access, however can dry up when it is hot
What are sources of fresh water?
Lakes, rivers and aquifers
What are the 3 main problems of manufacturing and packaging ?
Energy use, release of pollution and production of waste products
What is the manufacturing and packaging process of plastic bags?
Hydrocarbons need to undergo fractional distillation and these are cracked to form alkenes. These then undergo polymerisation
What are limitations of LCAs?
There are so many steps, so almost difficult to quantify them, they can be manipulated to support a company and
What is desalination?
The extraction of potable water from seawater
What are 3 sources of waste water?
Domestic (household), agricultural systems (nutrient runoff from fields and animal waste) and industrial (factories that make and use chemicals)
What can the remaining digestive waste from sewage sludge be used as?
A fertiliser as it’s rich in nutrients
How can waste water containing toxic substances be removed?
Adding chemicals to precipitate metals or using UV radiation to break them down
How is waste water better than fresh water?
It is easier to treat
What is the process of recycling glass?
It is separated by colour, crushed and melted to be reshaped
What is the manufacturing and packaging process of paper bags?
The timbre needs to be pulped: Broken up into little pieces and soaked releasing loads of energy and producing waste
