Water Treatment - Freshwater treatment
- Created by: Luke Mitchell
- Created on: 16-01-13 21:29
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- Water Treatment - Freshwater treatment
- 1).Screens
- metals grills or meshes are used to remove floating vegetation, plastic and paper that would clog later proccesses
- 2). Sedimentation
- the water is allowed static to enable suspended solids such as silt to settle
- 3).Aeration
- 1) bubbles of air or water sprays used to aeroate water and ensure a high dissolved oxygen content
- 2) water sources that are anaerobic may contain hydrogen sulfide from decay of organic matter making water smell bad
- 3) some dissolved metals that are toxic or give water bad taste removed by aerations as become insoluble
- 4)Flocculation/ coagulationand claraification
- 1) clay particles don't settle out in sedimentation lagoons because electrostatic charges on surface cause them to repel each other
- 2) mixed quickly with water and passed into clarifer tank where particles settle out
- 5). Filtration
- filters such as sand filters used to remove any remaining solids and bacteria
- 6). Activated carbon filters
- particles of activated carbon are used to remove organic chemicals e.g. pesticides and substances that have bad taste
- 7). Sterilisation
- 1) addition of chlorine, ozone or exposure to UV light used to sterilise water/kill pathogens
- 2) chlorine is most common methods used, but if source is peaty will contain organic matter which would react with chlorine forming harmful toxins so ozone used to break down pesticides
- 8). Fluoridation
- fluorides added to water in some areas to improve dental health of people that drink the water
- 1).Screens
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