water treatment Flashcards
why is access to safe water important?
protect public health
what are the objectives of water treatment?
water that is chemically and biologically safe for for human consumption. Potable (water that can be consumed without concern) & palatable (water that is pleasing to drink
what are the NZ drinking water standards?
- protect public health
- minimize unnecessary monitoring
- appropriate for large/small and public/private water supplies
what are physical water quality parameters?
turbidity (cloudiness), colour, taste, odour, temperature
what are chemical water quality parameters? (CFILMSSZ)
removal of chemicals such as chlorine fluorides, iron, lead, magnesium, sodium, sulphate, zinc
what are the 3 main water contaminants in NZ?
pathogens (from human and animal waste), sediments (from soil erosion), and nutrients (from farming and agricultural activities)
what is water treatment?
reduction or removal of impurities from water to acceptable concentrations
what are the 3 types of impurities in water?
suspended solids, colloidal solids, dissolved solids
what are the 2 types of water treatment metheods
unit operations (removal of contaminants via physical forces), and unit processes (removal of contaminants by chemical or biological reactions
what are some examples of physical treatments methods (unit operations)?
sedimentation (settled suspended solids), filtration, flocculation (minute particle combine to form larger particles), absorption, air stripping, aeration
what are some chemical treatment methods (unit processes)
coagulation (from liquid to gel), softening (removal of metal cations in water), chemical precipitation, disinfection with chlorine or ozone
what are the 3 water treatment schemes?
simple disinfection & softening plants (for groundwater), filtration plants (for surface water)
