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42 Cards in this Set
- Front
- Back
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What does reverse osmosis do, in essence
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It equalizes concentration of salt and fresh water by using the method of osmosis (solvents moving from high to low concentration) and a semi permeable membrane capturing the salt in between.
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Define polluted water
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Water that is unsuitable for drinking, irrigation, industrial use or washing
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Sources of heavy Metals (eg. cadmium, copper, mercury, lead, zinc)
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Cd: Rechargable batteries, metal plating and pigments
Cu: household plumbing, copper mining and smelting Hg: Mercury salts as fungicides, batteries, mercury cells in chlor-alkali industry, discharge from pulp and paper mills |
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Sources of pesticides
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Agricultural practices
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What are two ways of desalination
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1) destilation
2) reverse osmosis |
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Percentage of earth surface is covered by water
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75%
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Water properties (3)
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Polar, has hydrogen bonds, can dissolve many chemicals
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Define reverse osmosis
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When the pressure applied to the sea water is greater than the osmotic pressure then the flow of the solvent takes place in the opposite direction
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Percentages distribution of water on the Earth's surface
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97.3% ocean, 2.1 % glaciers & ice caps, 0.6% ground water, 0.015% lakes, rivers, 0.001% atmosphere
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Anaerobic biological process (dentrification)
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Turns N in NO3 into N2
6H + NO3 +5e -> N2 + 3H2O |
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What are aquifers?
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Natural underground reservoirs
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Ground water
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0.6%
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Oceans
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97.3%
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Glaciers and ice caps
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2.1%
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Cadmium sources (3)
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rechargeable batteries, metal plating and pigments
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Activated sludge process
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Requires aeration in which air is bubbled using large blowers through sewage mixed with bacteria-laden sludge. This allows for bacteria to mix with sewage in order to oxidize and break down organic matter
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Copper sources (3)
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household plumbing, coppper mining and smelting
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Hg source (4)
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Batteries, mercury salts, mercury cell in chlor-alkali industry, discharge from pulp and paper mils
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Define distillation
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A process that allows separation of a volatile liquid from non-volatile materials
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Most expensive but most affecive sewage treatment
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Tertiary
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Primary sewage treatment removes
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30~40% of BOD waste
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Define semi-permeable membrane
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A substance that only allows water to pass, not ions or molecules
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Denitrification
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Anaerobic biological process which turns the nitrogen in nitrates back to atmospheric nitrogen, N2
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Mercury sources (2)
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Batteries, mercury salts as fungicides
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Secondary sewage treatment
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Removes 90% of suspended particles
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Settling tanks serve the purpose of transferring:
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Smaller, heavier objects to landfills
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Purpose of sewage treatment
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Removal of haardous materials, reduction of BOD (Biological Oxygen Demand) of the sewage and killing of microorganisms prior to discharge.
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Adsorption
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The attraction of a substance to the surface of a solid substance
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Carbon bed method uses:
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Activated carbon black that readily adsorbs organic chemicals from waste waters
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Polluted water
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Water that is unsuitable for drinking, irrigation, industrial use, or washing
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Sewage
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Water-carried wastes that flow away from any community
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Types of sewage treatment
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Primary, secondary, tertiary
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Primary sewage treatment
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screens (trap large objects) --> settling tank (removes rocks, stones, etc.) --> sedimentation tank (flocculation, removes flocs and sludge) --> tank with chlorine or ozone to kill bacteria --> a) to rivers or b) to secondary treatment
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Osmosis
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The natural tendency of a solvent such as water to move from an area of high solvent concentration (purer water) to an area of low solvent concentration (less pure water) through a semi-permeable membrane
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Tertiary sewage treatment
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Removes dissolved inorganic substances; nitrate ions and phosphate ions
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Dioxins (pollutant) source
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By-products of industrial processes such as waste incineration
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Speeding up sedimentation by:
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Adding chemicals which allow suspended particles to join together to form large clumps
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Flocculation
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When chemicals are added to speed up the fermentation process by allowing suspended particles to join together to form large clumps
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Polychlorobiphenyls (PCB) source
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Coolants and lubricants
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Nitrates source
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Nitrate fertilizers for farming
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Desalination
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Remove salts from sea water and brackish water to produce fresh water
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Example of a chemical used for flocculation
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Al2(SO4)3
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