- Current section: Introduction
- Learning outcomes
- 1 Natural waters
- 2 Pollutants
- 3 The extent of water pollution
- 4 Treatment of water supplies
- 5 Sewage treatment
- 6 Summary
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Energy resources: Water quality
Water is arguably the most important physical resource as it is the one that is...
Water is arguably the most important physical resource as it is the one that is essential to human survival. Understanding the global water cycle and how we use water is essential to planning a sustainable source of water for the future. In the UK there are areas where water supplies are limited, shown by recent droughts. Globally, there are many areas that do not have enough water to support the current population adequately. Decisions will have to be made on the best way to use water in a world where there is climate change.
By the end of this unit you will:
- Describe the chemical compositions of natural waters, and explain how and why these compositions vary;
- Describe the main sources of water pollution, the main types of pollutant and how each type may be controlled;
- Outline the extent of water pollution in the UK and in selected global locations;
- Identify the criteria for drinking water acceptability in the EU, and outline the processes used to treat water for a public water supply;
- Outline how sewage may be treated before discharge to the environment.
Energy resources: Water quality
To judge what constitutes poor quality or polluted water, we must first understand the properties of naturally occurring waters. Natural water is not just H2O: all natural waters contain dissolved and suspended substances seawater is an obvious example of water containing dissolved salts, but freshwater does also, although at a far lower concentrations. Water pollution is defined as a change in the quality of the water due to human activity that makes the water less suitable for use than it was originally. It is difficult to set absolute standards of purity that apply for all uses of water however, because water that is considered clean enough for one purpose may be too polluted for another.
This unit is from our archive and is an adapted extract from Earth's physical resources: origin, use and environmental impact (S278) which is no longer taught by The Open University. If you want to study formally with us, you may wish to explore other courses we offer in.
This is an extract from an Open University course which is no longer available to new students. If you found this interesting you could explore more free Environmental Science course units or view the range of currently available OU Environmental Science courses.
Copyright & revisions
Originally published: Monday, 11th July 2011
- Creative-Commons: The Open University is proud to release this free course under a Creative Commons licence. However, any third-party materials featured within it are used with permission and are not ours to give away. These materials are not subject to the Creative Commons licence. See terms and conditions. Full details can be found in the Acknowledgements section.
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