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13 Cards in this Set
- Front
- Back
Water Quality Parameters |
- colour, taste, odour, turbidity
- pH, chloride high calcium/magnesium
- Arsenic, lead, synthetic carcinogens
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Treatment Requirements |
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Basic Water Treatment Process |
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Treatment Process |
Aeration: Remove volatile solutes and odorous substances - H2S, CO2 CH4 - methane thiol, bacterial Chemical Pre-treatment: Removes algae/excess colour Sedimentation: Solid/liquid separation - Natural sedimentation; gravity Coagulation: Add aluminum or iron salts,changes electric charges of particles, facilitating aggregation Flocculation; coagulated mix form larger flocs Flitration: Commonly sand Disinfection: Killing pathogenic microbes, prevent regrowth - By-products; Halogenated hydorcarbons |
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Advanced Water Treatment |
Water from standard treatment is taken to a high quality product. |
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Taste and Odour Compounds |
Produced as metabolic by-products by Cyanobacterial blooms |
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Granular Activated Compound (GAC) |
Produced by heating organic matter in a controlled atmosphere. - Used in rapid gravity filters GAC is positively charged therefore able to remove negative ions from the water - highly porous Not effective in removing heavy metals. |
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GAC Adsorption |
Liquid and gas molecules are concentrated on a solid surface. Physical Adsorption Attractive forces at the surface of pore walls attract contaminants through pore channels Chemical Adsorption Hydrogen and oxygen on surface (as phenols, carbonyls, esters, etc), take chemical reactions |
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GAC Adsorption: Adv. / Disadv. |
Advantages:
Disadvantages:
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Biological Activated Carbon |
Removes disinfection by-products and degrades many organic pollutants. |
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Ozone (O3) Adv. / Disadv. |
Unstable gas generated by passing an electric discharge through clean, dry air/oxygen. - Decays quickly in water, used together with Chlorine. The most powerful disinfectant in water treatment. Effective against difficult to treat protozoan parasites. e.g. Cryptosporidium and Giardia Adv. Effective at killing viruses Transforms/breaks down many substances Disadv. High energy consumption can form some toxic compounds (eg.bromate) |
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Ultraviolet Radiation (UV) Adv. / Disadv. |
UV irradiation produced by mercury lamps kill bacteria and viruses. - uncertainty; Cryptosporidium and Giardia Wavelentgh 250-280nm Adv. - No chemicals to water - Equipment relatively simple to operate/maintain Disadv. - Impurities that cause colour/turbidity can reduce effectiveness UV cannot penetrate - |
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Reverse Osmosis |
Solubilisation diffusion technique uses semi-permeable membrane. Membrane acts as barrier to dissolved salts and inorganic molecules |